In recent years, the popularity of the car, NOx, COx increased displacement, environmental pollution and problems of global warming worse. To this end, many countries are actively implementing the hybrid electric vehicles and electric vehicles to replace conventional cars. But more importantly, these new energy vehicles require high energy density, high voltage, rapid charge-discharge characteristics of energy storage media in support, such as lithium-ion batteries. Battery charge and discharge as a practical device to fully play its role, its large capacity, high accuracy, reliability has been increased. To effectively play the battery performance, this article will serve as high capacity batteries for the design of electrical systems. hp Pavilion DV1000 battery hp Pavilion dv6 battery

System Components 1

(1) Overview

Battery charge and discharge device circuits are mainly two. A kind of the linear amplifier (Charger) + load impedance (electric shock), etc., hereinafter referred to as composition 1, while the two others by the system for the converter + inverter (electrical charge and discharge) with the following form short 2 first to compare the advantages of both.

The battery charger is now on the market is about half of all 1, because the charger phenomenon consisting of fever, and large, use the launch site restrictions. In the words of the electrical work, if you want two-way transmission of energy, is then a 2 is the best.

Here for form 2, on two different ways to discuss the design of circuits.

The process of designing the system first type voltage inverter combined buck-boost converter and two-way combination of a battery charge and discharge device, ahead of the second draft is adopted high supply load capacity and electronic equipment (hereinafter referred APL2). For APL2 can turn any battery voltage, current, such as food or load may be a 0kW input and output (making the voltage 0 ~ 200V or 400V). 417066-001 hp pavilion dv6000 battery

The first step of design, the system and the isolation between the power transformers, the reactor section Buck converter, the switching unit so small, the existence of certain problems. Meanwhile, the subsidiary of the high frequency transformer isolation circuit, the inhibition of cells pulsed current buck converter, and the reactor is essential.

The approach of the second project, namely, the use of APL2, does not change depending on the battery to change the nameplate capacity of the circuit. At the same time, increased through the series circuit and the charge and discharge current characteristics of small and light.

As the design of a case, the nominal capacity of 1 0kVA the same design conditions, the design results of this comparison is the second volume of the approach to device design is the first design approach 1 / 2. Based on the above analysis and comparison, this implies the use of APL2 and the battery discharge device. hp 520 battery hp 530 battery

(2) The base composition

The system settings simply by a fiber optic cable can be connected and APL2 user’s computer. Meanwhile, the use of this system can be achieved within the Windows system, the development of battery charging and discharging system

(3) Control scheme

Figure 2 APL2 constant current modes when the control block diagram. Enforcement costs and waste, downloaded from a computer model data that the value of outstanding orders, for the constant current control. While charging, the battery voltage reaches the predetermined maximum voltage value, automatically switches to constant voltage mode control and load slow.

Shown in Figure 2, the charging circuit and discharge instruction loop to switch contacts, but is actually using the DSP to pass the program, almost no switching delay. APL2 as a battery charge and discharge device, without changing the internal structure, it can be applied directly to control the characteristics of the circuit. apple macbook pro 15 inch battery apple macbook pro 17 inch battery

2 Application Example

The capability of an application APL2 large, high-voltage ion battery charge and discharge system. battery charge and discharge unit as an object, the maximum voltage of 336V, load and discharge current of 00A ± 1. Figure 3, the composition of the system, Table 1, the basic specifications for the APL2.

Rated voltage of the current system for 400V/25A APL2, to increase capacity by using the master-slave, the maximum can be parallel four APL2, can load and unload under 100A. Figure 4 shows the 0 ~ 90 load voltage and current waveforms of the elbow, recharging the battery type switching power stage has been the response waveform, Figure 5 shows the 0 waveform ~-90A of current when the battery voltage discharge of the battery, when the current changes have been the step response waveform. The current from the battery, first specify the output current APL2 home, while the slave is responsible for monitoring the host and release current value and change orders. apple ibook g4 14-inch battery apple macbook 13 inch battery

The system 1 00A may be performed quickly on the charge current S-velocity and discharge control can be used to charge the lithium-ion battery and discharge characteristics of the basic test.

3 Conclusion

According to this design method can be used directly for APL2 load capacity of the battery and draining device, the embodiment of the system small and lightweight, the corresponding reduced system development between Japanese inches. In this paper, we introduce the charge lithium ion APL2 and discharge system of the situation, it can also be used for loading double-layer capacitors and rejection, EV and HEV Motor · ninth power system dynamics and other areas, and space-saving and energy saving features. apple a1189 apple ibook g4 12-inch battery

In the fuel cell electric vehicles, high power DC / DC converters and other control circuits, motor controllers and other equipment placed together between Yao radiated electromagnetic energy, usually associated with the shield and shell mode gap shield for protection against radiation suppress interference. In addition, the mass signal eliminates the outside world or other equipment with high VEGF power DC / DC interference, the key is to choose an appropriate reference point for the circuit and line grounded in sound public distribution. Dell Inspiron 1525 battery Dell Vostro 1520 battery

High Power DC / DC converter control circuit anti-jamming design

Control circuitry is the high power DC / DC are an important component of good design advice can significantly improve the immunity of the circuit.

High Power DC / DC converter control circuit mainly by the power supply, the sampling of signals, communication signals and the driver modules, to avoid interference between signals in the circuit design at its isolation, as shown.

VEGF in high power DC / DC converter control circuit, the power module is commonly used in isolated DC / DC module, realized the power of entry and exit of electrical insulation. isolation of the sampling signal, including the isolation and the isolation voltage of sample collection. Communication signals using optical couplers HCPL0600 isolation to reach the entrance of the CAN bus and output signals of the optical isolation. VEGF with DC / DC converter output is bigger, so that using IGBT power switch and IGBT drivers with different specifications for different methods of isolation. General IGBT driver with low power isolation TLP250, medium-power IGBT drive for a more EXB841/840 Series modules driver isolation, high power IGBT modules or ultra-high power may be used to achieve the 2SD315A drive isolation. Practice shows that the isolation of each functional module, the control circuit can be greatly reduced interference between the different modules to ensure the reliability of signal transmission and signal processing precision. Dell Latitude D610 battery Dell Inspiron E1405 battery

High Power DC / DC converter design software interference

High Power DC / DC converters are usually controlled by DSP, the anti-jamming design software is also very important. High Power DC / DC conversion software interference of two main aspects to consider: DSP technology for filtering interference immunity and Software Technology, the first is mainly due to the interference against the procedure because “run off”, which is primarily to eliminate the signal interference to improve system accuracy.

DSP technology, anti-jamming

VEGF in high power DC / DC converter operation, once the interference DSP control system will have very serious consequences, even make the system of fuel cell electric vehicles paralyzed, so when designing the real system, are considered as interference occurs, the DSP system against its own measures. Dell Vostro 1220 battery Dell Vostro 1220n battery

To improve the immunity of DSP, the new DSP controller (as TMS320LF2407A) module integrates a watchdog timer (WDT), used to run the monitoring program is a combination of hardware and software procedures for managing anti Fly-measures. WDT is used to generate the material of the main cons or timer trigger monostable T, the counter or trigger basic single autonomous and stable, termination synchronization output line reset the DSP and time allowed by the DSP control software.

Under normal circumstances, the program began after the WDT, and in some time, the time T reset to clear, so the timing WDT overflow will not occur because no effect of sleep normally. Interference of Yichang in the context of the situation, the destruction of temporal logic processor implementation of the program, chaos, Bu Keneng WDT cleared periodically, Zhe Yang a time when the WDT overflows, the output reset Shi Ji Tong DSP processor Baituo Yin Er in a temporary disruption paralysis. dell inspiron 2600 battery dell inspiron 2650 battery

Antispyware

In this article, a filtering technology VEGF high processing power DC / DC sampling data. High Power DC / DC converter will be collected using the analog controller filtered sent to DSP A / D converter channel, launched by the software programming / D conversion, to obtain the value of the sample A / D integrated in the register in.

DSP signal interference Duocheng around the shape of burrs, a relatively short duration of action. Sampling of the analog DSP, it can be repeated on the same analog A / D conversion, and several times the value of temporary storage in the sampling area of internal data. After repeated sampling when using data filtering algorithm and multiple methods of sampling the average value of data processing software that can improve the fight against-interference, improve data accuracy and sampling accuracy. dell inspiron 1520 battery dell inspiron 1521 battery

Conclusion

In this paper, high power DC / DC converter and the main sources of interference suppression measures to control the electromagnetic signal circuit isolation and design software to interference VEGF high power DC / DC compatibility electromagnetic study and an effective solution to the VEGF high power DC / DC EMI. With EMC Design VEGF high power DC / DC converter has been applied successfully developed by Tsinghua University, the fuel cell buses, technical indicators are used to meet the vehicle requirements, works well. dell inspiron 1720 battery dell inspiron 1721 battery

Currently, electric vehicles to fuel cell (FCEV) become the main direction of technological innovation of the automobile. System for Fuel Cell Electric Vehicle Power consists of an engine fuel cell, DC / DC converters, battery, motor controller (inverter) and the DC motor, system acquisition CAN bus data and composition of Figure 1. Including DC / DC converter controls the production of fuel cells and energy transmission and conversion, fuel cell electric vehicle key components. In the fuel cell electric vehicles for the course, DC / DC converter in which the electromagnetic environment is very complex and many forms of electromagnetic interference, has seriously affected the normal operation of the DC / DC converter. Therefore, the study with DC DC Converter VEGF electromagnetic compatibility DC / DC and battery electric vehicles to fuel and reliable operation is important. Dell Inspiron 1721 battery Dell Inspiron E1505 battery

High Power DC / DC converter main source of interference and electromagnetic compatibility design

VEGF with DC / DC converter is a device for power conversion, electromagnetic compatibility electromagnetic environment in VEGF has a significant impact. VEGF with DC / DC working on the world a strong electromagnetic interference, not only interfere with the VEGF, but also affects the DC / DC converter control system of their own work. Therefore, VEGF to improve system performance must VEGF with DC / DC The search for electromagnetic compatibility, electromagnetic interference generated by its (EMI) effectively inhibited. Dell Latitude D830 battery Dell Inspiron 1150 battery

High Power DC / DC converter main source of interference

VEGF with DC / DC power converter is generally larger, often choose as IGBT power switches. IGBT power switches work produced during the high dv / dt and di / dt and the increase of peak current and voltage, which is VEGF high power DC / DC converters to generate the most fundamental causes of electromagnetic interference . In addition, the power switch on and off instantly, as inductance and distributed capacity of the existence of the inductor is a high frequency oscillation, these factors have a strong electromagnetic interference, which VEGF high power DC / DC converter performance particularly sensitive. This electromagnetic interference severely affected vehicle controller and CAN communication, communication can often lead to error, not the normal communication. CAN communication interference waveform is displayed after the transfer. From the figure, it is clear that the converter switching noise superimposed on the pulse on the CAN communication and the increase was significant. In addition, EMI will also make a serious high-power DC / DC output ripple of the converter is too large, the ripple is too large direct impact on high power DC / DC converter performance. Dell Vostro 1500 battery Dell XPS M140 battery

High Power DC / DC measures electromagnetic interference suppression

Currently, inhibition of the high power DC / DC EMI measures reduce the main sources of interference intensity of electromagnetic interference, electromagnetic interference cut the transmission, distribution and rational use of sensitive components and the shield design signal ground.

● reduce the intensity of the interference of electromagnetic interference

High Power DC / DC converters generate electromagnetic interference is mainly due to the rapid changes in voltage and current, and thus need to minimize the voltage and current exchange rates (du / dt and di / dt) . The most common method is to increase the absorption circuit, the circuit can inhibit the absorption of electromagnetic interference, the basic principle is that when the switch is turned off to provide diversion, savings in the parasitic absorption parameters of energy distribution, thus preventing the appearance of interference. More technology soft switching converter is the focal point of research in recent years [4], VEGF high power DC / DC converter using passive soft-switching resonant flexible technology can significantly reduce the process of switching / dt and di / dt, not only to reduce switching losses, but also significantly reduces electromagnetic interference. In addition, by optimizing the power switch control IGBT, selecting the power button IGBT drive voltage and gate resistance, may also reduce interference from high power DC / DC EMI. Dell Vostro 1710 battery Dell Latitude D810 battery

● cut channels of electromagnetic

VEGF high power DC / DC electromagnetic interference generated mainly by conduction disorders. The most common method is DC / DC converter input and output filter capacitor installed. To reduce VEGF high power DC / DC on the CAN communication interference, in converter input and output plus an appropriate amount of capacitors grounded, effective communication can improve the waveform.

VEGF in high power DC / DC converter, the output voltage or current ripple is an important indicator of food. Figure 4 in the high power DC / DC converter to connect the CLC filter output, the converter output voltage waveform smooth, reduced switching noise, filtering is obvious. dell inspiron 6400 battery dell inspiron 640m battery

In addition, VEGF high power DC / DC converter switch to a dozen kHz frequency IGBT turn on and off the circuit can have a high incidence of harmonic current output voltage fuel cell. Therefore, DC / DC converter input and output are generally parallel capacitor (electrolytic capacitors without any sense of capacitors in parallel). No sense capacitor filter circuit can occur because of interference radiation frequency resonance, while the electrolytic capacitor to stabilize the output voltage of fuel cells and reduce the intensity of the radiation, and reduces the DC / DC output voltage ripple.

● rational distribution of sensitive components dell inspiron 6000 battery dell inspiron 630m battery

VEGF high power DC / DC converter contains many sensitive components (such as Hall sensors in progress), these sensitive components are very sensitive to electromagnetic interference. VEGF in high power DC / DC Converter for switching on actual layout of components usually sensitive to the power switch in the IGBTs, freewheeling diode and a transformer at high frequency, the farther Xian stranded signals and reduce the wiring distance This can significantly reduce the current noise signal, improve the control performance. Meanwhile, VEGF high power DC / DC converter wiring connection, we should try to be sensitive to the signal line of IGBT power switch, diode and high-frequency transformers and other strong sources of interference. At the same time, not with a high voltage AC signal and high frequency pulse signal is put together, should ensure the proper distance. dell inspiron 5150 battery dell inspiron 5160 battery

LTC4085 is a portable USB power manager self monolithic ideal diode controller and standalone linear battery charger. LTC4085 PowerPath control with, or the USB VBUS power adapter AC to power the system load, and single-cell lithium ion / polymer battery charger. To comply with USB specifications to the limit, LTC4085 automatically when the system load current increases, thus reducing the battery charge current. To ensure that the battery is fully charged when the bus connection is not used as such, the IC by the USB bus to power the load Shusong, but have no power to the battery practice. Once the power is off, the current through a 200mΩ ideal diode low loss rate of the battery to the load, thus reducing the voltage drop and power dissipation. Provided advice to drive an optional external PFET GATE circuit for connecting peripherals to the case in the application necessary for the overall ideal diode impedance below 30mΩ the following. LTN141W3 LTN141X7 LTN141X8

LTC4085 unique feature is the AC adapter can detect the access and use it as a kind of power system load while charging the battery backup power. LTC4085 also provides access to an AC adapter in the case of higher values to USB specifications allow (100/500mA) rating (up to 1.5 A) to charge the battery option, so they can dramatically increased rates of charges the battery. The total cost of time late charge by an external resistor to set. When the load current decreases, the load timer period will be automatically extended to ensure that the battery is always fully charged state. Additional features include automatic recharge, NTC thermistor input, input adapter is automatically removed the battery, limiting the inrush current, reverse current blocking, lock-out under-voltage and thermal setting.

LTC4085 float voltage is preset at 4.2V from 0 to 85 ℃ temperature to ensure the accuracy of 0.8%. Charging current can be easily adjusted using a resistor. The optimum temperature for charging the battery of pre-treatment and certification will automatically be set to 10% of the total flow of the trickle charge current battery until the battery voltage exceeds 2.8V up at. LTN141XA LTN141XB LTN141XC

For, like GPS navigation devices, PDAs, digital cameras, digital photo player, MP3/MP4 players and other handheld devices, offering the USB port and the input voltage, high load capacity and battery has many advantages such as energy USB if you have not driven on the road to bring the convenience of the charger, a laptop from a PC or other device with USB port to power your device. Such as FireWire, 12 ~ 24V AC adapter or car adapter, car power can input-output high voltage to provide a higher speed of USB charging, and allow more places (like cars), taxation , which is to improve facilities One of the keys to portability.

Convenience features and high power

LTC408 And LTC408 -5 Is a portable USB power manager self, ideal diode controller and standalone high-voltage battery charger for high efficiency. To achieve efficient load their switching topology can be adapted to a variety of appetizers, including up to 36V (40V max) of high voltage (like 12V AC adapter, car adapter and a FireWire port). In addition, they also accepted such as adapters and USB 5V supply low voltage. LTC408? -5 With PowerPath control feature, available on the USB or power adapter to the equipment and materials of the lithium-ion battery charging, but also the introduction of a severe shortage of battery power is exhausted or the situation to achieve “instant-on” operation. LTN154X1 LTN154X2 LTN154X3

To comply with USB specifications to the limit, LTC408? -5 Load current increases in the system automatically reduces battery charge current when. To ensure that a fully charged battery is connected to a full charge state when the bus termination, the IC by the USB bus to transport power to the load, but did not take lessons from battery approach. Once all food was removed, then the current through a 200mΩ ideal diode low loss rate of the battery to the load, thus reducing the voltage drop and power dissipation. Provided to drive an optional external PFET circuit board to the case in the application necessary for the overall ideal diode impedance below 30mΩ the following, which will enhance the work efficiency.

When LTC408? -5 Power from USB port to provide power management system allows the maximum available power, which increased by 2.5 W (500 mA x 5V) from the USB power solution available. In addition, it would, the system automatically adjust the load current lithium-ion / polymer battery charge current to maintain the total input current limit consistent with the USB. LTN154X7 LTN154XA LTN156AT01

LTC408 Switching regulator with output track the BAT-based adaptive control, which greatly improved its offer 1.2A charge current from the battery charger efficiency, because the output voltage of the switching regulator automatically tracks the voltage of the battery. LTC408 -5 from the input voltage high is a fixed 5V output, used in single-cell lithium-ion / polymer battery charger. The float voltage battery charger is preset to 4.2V, at intervals of 0 ~ 85 ℃ temperature to ensure the accuracy of 1.0%. Charging current can be easily adjusted through a resistor. The total cost of time late charge set by an external capacitor, and provides an output charge detection C/10 current. Additional features include automatic adjustment for temperature qualified charging heat to the NTC thermistor input, the battery will automatically recharge, reverse blocking and lock-out being energized. LTC408 -5 With flat (height of only 0.75 mm) 6mm 22-pin 3mm × tiny DFN package, and the guarantee of -40 ~ 85 ℃ operating temperature. dell gw240 dell rn873 dell y6142

BAT-track control output adjustment

LTC408 AT-Track function adaptive output control is a form. This is a battery charger and switching regulator integrated, so that the switching regulator does not produce enough to sustain the required voltage of the battery charger, but does not produce additional tension. Linearly supply for the product, the input voltage and voltage difference of the battery in the charging process is lost as waste heat.

Where implementation of a switching regulator, the switch to both ends of the pressure drop as large as possible is beneficial because it can effectively accomplish the (absorbed by the input current is less than the current supplied to the charger). dell gk479 dell nf343 dell pc764

BAT-Track function is responsible for detecting the voltage of BAT, and switching regulator output VOUT to adjust to the battery voltage VBAT exceeds 300mV, minimizing power loss caused by heat, can charge the battery properly and maximize reduce total electricity consumption. This greatly improves the efficiency of the battery charger. For example: When the load current IBAT = 600mA, VBAT = 3.7 V input voltage VIN = 5V charger, the charger efficiency (with the substitution method element) is as follows: 100 × POUT / (POUT + PDIS) = 100 × (× VBAT IBAT) / (× VBAT IBAT PDIS +) = 100 × (× VBAT IBAT) / (VIN x IIN) = (3.7 × 600mA) / (5V × 600mA) = 74%.

Conversely, if the charger voltage VBAT input exceeds 300mV the charger efficiency: 100 × (× VBAT IBAT) / (VIN x IIN) = (3.7 × 600mA) / ((3.7 V 0.3 V) × 600 mA) = 92.5%.

This difference in efficiency will significantly reduce energy consumption. In addition, if the battery against discharge and voltage VBAT to low, the minimum should be 3.6V VOUT, to ensure that the system load for a sufficient supply voltage. dell hd438 dell y9943 dell fk890

Handheld battery today engineers design equipment, they are the major challenges facing Suo Yi Xie minimize energy consumption and minimize Tigaoxiaoshuai, simplify design and reduce Chengben.

Many battery-powered portable electronics available today from the AC adapter, car adapter, USB port, or lithium ion / polymer. However, these sequences between different power supply control of self-management has great technical challenge. Throughout, the designers are trying to adopt a “discreet” way to accomplish this function, which uses a large number of MOSFETs, op amps and other discrete components, but during the meeting are likely to cause major system problems, and the influx of hot-plug and other current issues. Recently, even discrete IC solution also needs to use multiple chips to achieve a practical and integrated power management ICs can easily solve these problems. In addition, CI own independent operation also removes an additional termination for the realization of the need for an external microprocessor, thus further simplifying the design. LP154WX4 LP171W01 LP171WP3

When used, such as FireWire, is not regulated high voltage (> 5.5) AC adapter and cigarette lighter adapter, the adapter voltage source and portable devices, the voltage difference between batteries large. Therefore, the linear charger may not be able to solve the problem of high energy consumption, while the use of topology switching IC is able to improve efficiency and reduce thermal management problems. Note that when using USB, Lithium ion polymer battery or adapter input less than 5.5V to power the linear charger device power management is a more appropriate choice.

PowerPath control

With control device from PowerPath USB VBUS power adapter for his own power, and its lithium-ion rechargeable single cell. To ensure that the battery is fully charged when the connection is not used in the state of the bus, the IC directly through the USB bus power the load, rather than receiving power from the battery. Once removed from office, the current through an internal low loss ideal diode current from the battery to the load, thus reducing the voltage drop and power dissipation. LP171WP5 LP171WP6 LP171WX2

Features PowerPath control:

1. Food USB access adapter or battery;

2. In the OUT pin is connected to a circuit application and a battery connected to the power transmission BAT pin (assuming that access to external power, battery);

3. Does the battery charge current is regulated to ensure that the load current and load current and no more to define the boundary USB input current;

4. AC adapter current through an external device (such as power Schottky diodes or FET) connected to the output (load side);

5. With a unique feature, you can use the AC adapter to power the output power to the load while charging the battery;

6. Output pin of the load may be a priority in the current USB input. LT141X7 LT150X3 LTN141W1

Ideal diode

When the output / load current exceeds the input current or voltage input is removed, the ideal diode low loss battery to provide power. The ideal diode (not to load directly connected to the battery) to give the load a fully charged battery can power an external power to maintain full charge before the state abolished. Once the external power source is removed, the output voltage drops until the ideal diode forward bias is applied so far. Canada has the ideal diode voltage before the battery then provides an output to the load. Ideal diode voltage drop much lower than conventional diodes, and reverse leakage current of less. Small forward voltage drop to reduce energy consumption and self-heating, which prolongs the life of the battery.

Ideal diode has the following characteristics:

1. When the output / load current exceeds the input current, or when the input voltage is removed, the ideal diode components for supplying power from the battery; Dell Vostro A860 battery Dell Vostro A860n battery

2. The ideal diode (not to load directly connected to the battery) to give a full load power supply can recharge the battery in the external power source is removed to maintain full charge state Zhi Qian, and makes the unit even in a fully depleted by the battery cases to function properly;

3. Once the external power source is removed, the output voltage drops until the ideal diode forward bias is applied so far. It also has an ideal diode voltage before the battery then provides an output to the load;

4. If the battery is the only power source available or load current exceeds the input current has been set, then the battery will be filed by a bat and pins on the ideal diode circuit between the power transmission automatic load; Dell Vostro 1720 battery Dell Vostro A840 battery

5. Ideal diode (as well as recommended capacitors on pin OUT) allows IC to the body without using large capacitors in the treatment of high dynamic loads and the AC adapter or USB VBUS connection disconnection model /;

6. Ideal diode low loss path to power by reducing the IR drop extended run time battery.

Linear Technology Power Management IC Series for solving design problems above. In the field realize the function of two important new products LTC4085 USB power manager and high-voltage battery charger LTC408 Source Manager. Dell Vostro 1510 battery Dell Vostro 1710 battery

To accurately measure the magnitude of tension mV in itself quite a challenge, stand on chips for accurate measurement of temperature Bianhua O’clock Geng Xian Shi is difficult, because Zhu Yao Ji Shi is a work laptop in the room diannao, Huan Shi Jing Li temperature changes will be. For example, in the battery during the rest of the leadership, BMU in a FET maximum power from the battery, resulting in significant increase in chip temperature. And offset parameters are related to many changes in temperature, if not eliminate these effects will affect measurement accuracy. Atmel offset calibration method has been proved that taking into account the thermal effect is also very effective. Figure shows the effect of temperature has been completely eliminated, ensuring that migration is no longer an impact on the measurement accuracy. Dell XPS M1330 Screen Dell XPS M140 Screen

Bandgap reference voltage characteristics and the impact on the voltage measurement

Bandgap reference voltage is a key factor in access to high-precision results. The expected value of the gap voltage reference firmware will result in an actual gain error of measurement results, and in most cases it is the measurement of battery voltage and current measurement the main source of large error.

Standard voltage bandgap reference is proportional to absolute temperature by a (PTAT) current and a complementary relationship with the absolute temperature (CTAT) in the current composition of the two added together, can provide the change in stream temperature and relatively stable. This current flows through resistance, not the temperature change and the formation of relatively constant voltage. However, the shape of a curve of CTAT, PTAT and is linear, so be tension – temperature relationship graph is curved. Dell XPS M1530 Screen Dell XPS M170 Screen

BGR in the current level of production of certain differences (changes in output), making reference numeral 25 ℃, the curve of curvature of the flattest part of the shape and location changes occur, to Hence the need for factory calibrated to try to reduce the impact of this change, as shown in Figure 3 as a benchmark does not calibrate the changes made by the bodies of the source. At -20 ~ +85 ℃ temperature range, the maximum difference of -0.9 ~ 0.20%. Figure 3 shows the curves of two extreme values of the curve with most other devices there is a big difference.

BM devices commonly used in reference bandgap standard was calibrated against the change in rating, at 25 ℃ high precision. However, changes in curvature of the shape and location of compensation is also fairly common, and this generation and significantly related to changes in temperature, which makes high and low temperatures in the measurement of battery voltage n is not specific enough. In addition, it can not detect and display the shape of the curve was significantly different outliers. Dell XPS M1710 Screen Dell XPS M1730 Screen

Novel voltage reference calibration method

Under different temperature changes to achieve better performance, Atmel adds an additional mechanism for voltage reference calibration to adjust the temperature coefficient bandgap reference. The calibration step to adjust the curvature of the shape and position, and significantly improve the stability with temperature changes, as shown in Figure 4, the range of -20 ~ 85 ℃ temperature of 0.5 %, the biggest change. Note that the second calibration step can detect and display a very different form of the curve of outliers.

On the basis of factors of production cost criterion, in general, BM components are the implementation of the second calibration step. Because industry standards are packaged in a test device temperature, while the second school in two temperature standards required under the semiconductor device testing accurate simulation, which has the added requirements of high accuracy of the simulation are generally the second test will be a big step increase in costs. HP G50 Screen HP G60 Screen

Atmel is developing a new approach, minimizes the additional cost to conduct a second test step. Traditionally, the test of the second step requires a measuring equipment of high precision and complex arithmetic operations. In addition, each device under test, the first step of test data must be stored, and then recover in the second stage of testing. These requirements will increase the cost of the test. Atmel’s proprietary technology to take full advantage of the characteristics of the WB unit itself, the test equipment is required as a minimum: a precise external reference voltage through the use of onboard ADC to implement the measure; CPU utilization to perform computing tasks required, and the first step in using flash memory to store measurement data. Therefore, as long as the use of very low cost high precision test equipment will get the result. In this way, Atmel is able to test at a very low additional cost to provide peak performance. pb992a pb994a pb995a

Offset voltage with a precision of temperature measurement

When the battery is fully charged or fully discharged state, the voltage measurement will determine when to terminate the application or stop recharging the battery. Because the maximum and minimum battery voltage safety issues are not compromised, and therefore should be built with a guard (guard band) to ensure that all safety cases. More accurate measurement of voltage, protection zone will be less necessary, use the battery, the actual capacity will be higher. A voltage and temperature data, voltage measurements can be calibrated, and the conditions of measurement error voltage will be minimal. When taking into account the change in temperature, the measurement error is the main source of reference voltage drift. Figure 5 shows the use of the compensation standard reference compared to the curvature reference voltage caused by uncertainty. As indicated, the compensation curve can significantly improve the accuracy. f4812a hstnn-lb31 pb991a

Conclusion

To maximize the use of the battery after each charge of energy and prolong battery life without sacrificing battery safety, high accuracy is essential. To avoid increasing the cost of calibration, the inherent accuracy BMU for the highest possible. In addition, the council may make full use of resources and flexible MCU new calibration technique, we can achieve a good benchmark for the minimum cost, elimination of the temperature.

Figure 32 hours, a discharge cycle of the battery 10Ah, respectively 3h/1.5A, and 7h/0.6A 22h/60mA. temperature variation of ± 10 ℃, using resistance 5mΩ sense. Using the standard calibration method with a common BMU charge accumulation of errors is greater than 400mAh, in this case, the equivalent of 10Ah batteries for more than 4%. Atmel’s integrated solution using a proprietary analog design flexible calibration method can greatly improve accuracy. With these improvements, the following error may be reduced to 20mAh, equivalent to 0.2%.f2024b f4486b f4809a

Battery management of common problems

In selecting the lithium-ion battery, it must be on good management to ensure safety and to obtain the maximum capacity per cycle and longer life expectancy, which is usually the method used to join the management unit the battery (BMU). To achieve security, BMU must be able to ensure that the cell voltage of the battery temperature and current specifications are often in their production inside. This means that in the design of management systems of the battery must be able to take into account the worst-case conditions. To charge voltage, for example, the standard laptop battery voltage 4.25V following recommendations. To maintain the cell voltage does not exceed the ceiling, generally suggest that you first get into the BMU voltage measurement standard deviation, with the load voltage less than 4 times the standard deviation. For example, if the BMU measured voltage 4.25V, while the standard deviation of 12.5mV, the instruction immediately stop charging to 4.2 V. However, it was the battery pack in order to maximum capacity of a direct conflict. Because of the higher charge voltage, the greater capacity. Similarly, when the battery voltage to the recommended cutoff (EOCV) and the discharge voltage cutoff (EODV), worn batteries as to prolong battery life, it is necessary avoid excessive charging voltage and low voltage discharge. Dell Vostro 1720 Screen Dell Vostro 1721 Screen

The importance of accurate measurement

Accurate battery voltage measurement accuracy and the need to define the margin EOCV EODV security (safety margin). The more accurate measure, to remain in the recommended limit of the smallest margin of safety required. Thus, measurement of voltage out, charge and discharge at the close of the recommended value and EOCV EODV without sacrificing security, have braved the battery capacity without the risk of premature deterioration. Therefore, the measurement accuracy of load flow calculation to ensure the accuracy of the load is also crucial.

Must take into account temperature changes

Be good to a precision of temperature measurement sets is not difficult, though, when the battery of the BMU Assembly will be easier for calibration. However, the actual situation, the battery generally withstand different temperature fluctuations, so that the temperature drift is to distinguish between genuine high performance general BMU BMU and the key parameters. Dell Vostro A840 Screen Dell Vostro A860 Screen

Changes in temperature, high voltage measurement accuracy of the parameter key is derived from ADC gain (gain drift) and the reference voltage drift (drift voltage reference). For 4200 mV voltage offset voltage measurements generally less 3μV in the design itself, which is negligible.

To accurately measure the load current (load flow), but also take into account many other parameters to minimize the sense resistor voltage drop. After the ADC offset calibration, the ADC zero drift, gain drift ADC, drift and time base reference voltage drift, they all have a significant impact on accuracy. For small current, the gap in the area with the most important parameters, in case of large currents, the gain error, the reference voltage and time base are becoming major factors.

Temperature change may be through a number of temperature points calibrated to some extent, on compensation, but the high cost of these programs, generally not for the majority of the battery manufacturers to adopt. Therefore, a good BMU must have the slightest change in temperature, and battery design must take account of changes in the worst BMU to ensure the safety of the design. Dell XPS 1530 Screen Dell XPS M1210 Screen

Current measurement: the basic power meter accuracy

To achieve a good design of lithium-ion battery, the most effective way to accurately track the flow of charge the battery inside and outside. To some extent, can be measured using the appropriate voltage to compensate for the open circuit voltage (OCV) and state of charge (SoC) for a constant relationship between the causes of the error of Load Flow. Some of the most advanced battery lithium-ion has a very flat voltage characteristic, which makes the use of OCV measurements to calibrate the measurement error is now more difficult. While there is some measurement error voltage, it could lead to a significant difference calculation SoC. Therefore, only the current measurement to ensure proper and accurate time base for best accuracy. hp pavilion dv6000 battery hp pavilion dv8000 battery

As mentioned above, in the case of low current, the current measurement error caused the biggest reason is that in the current measurement ADC offset, and there are already several technologies can reduce this gap. Among them, the technology most commonly used is the law in a controlled environment to measure the gap, and then once in the two measures Mei less offset. However, this method has a weakness, is not considered to offset drift. Figure 1 shows the number of technology components for the residual value after the compensation. Management unit the battery from Atmel is a better way, but the cyclical changes ATmega16HVA adopted by the polarity of the current measurement to cover the shift is an example. Although the use of this method still remains a very low but constant offset, however, the small gap remaining open only to protect the FET were measured before and through the battery to supply DC current, it can be removed. Figure 2 shows, using this method can significantly reduce the offset, while the BMU Atmel leeway in the residual error of quantization levels. The advantage of eliminating the offset accurately measure very small currents, while the shifting device important, you have to stop at a certain point on the measurement and began the current projections. Some BMU using 5mΩ detection of resistance, providing up to 100mA of blocking zero area or dead zone. For laptops as an example, it is a very significant amount of power, enough to maintain an operating mode for very long. hp pavilion dv4000 battery hp pavilion dv5000 battery

The accurate measurement of low current

For a given size of the sense resistor, current measurement ADC offset error is often limited their ability to measure the current minimum level, causing a low value sense resistor and the die area required (in this case because the current level is too low to collect fees flow) must be significant trade-offs between the two. Recently, most equipment manufacturers are looking for low energy consumption, and possible ways to maintain the low power mode, to ensure an accurate measurement of low current access technology becomes increasingly important. hp pavilion dv1000 battery hp pavilion dv2000 battery

This pricing method is characterized by a constant current charge until the load at a certain voltage (the equivalent of battery voltage at output), stop charging and current high (or low current) the discharge to the polarization, and a constant high charging current, and thus in turn to charge and discharge. Pulse frequency of discharge increases with sufficient human capacity, the pulse width with sufficient load increased human consumption. When the load capacity and landfill capacity is roughly equal, the battery is fully charged, the immediate cessation of charge. LTN141XB LTN141XC LTN154X1

Under this approach, which has a variety of programs to achieve fast charging batteries? In this way, free initial depolarization measurements. Canada must implement measures polarization pulse width decreases continuously, so that the current average load fell rapidly, to extend the charging time.

4) Constant current discharge to improve the load pulse bias voltage charging method

This method is constant current charging and constant voltage discharge pulses to improve the polarization of the fast charge. It is based on constant current (eg, IC) charge when the battery voltage reaches the charging voltage output (voltage of single cell battery. 2 35 ~ 2.5V), stop charging and discharge (such as current releases of the width of 2 ~ 3C, the pulse load 1 ms), and then Canada after a depolarization pulse discharge, with integrated tracking device to increase the charge voltage increased control (to improve point voltage output) to increase speed and improve the full extent of the burden. Another method and the same constant current constant voltage. LTN154X2 LTN154X3 LTN154X7

5) Sets the charging voltage fixed frequency pulse charging method of discharge to the polarization

Characteristic of this method is that the burden of constant amplitude of voltage pulses, the loading process progresses, the emf of the battery increases gradually with decreasing load current amplitude, the pulse charging current constant frequency pulse between the two load Add depolarization pulse discharge.

6) The charge and discharge voltage and discharge frequency selective load depolarizing pulse charging method

Characteristic of this method is that the process of recharging the battery in accordance with the polarization Qingkuang select the frequency pulse discharge and collection of late the battery terminal voltage limit values of the pre-selection, and limited decision to allow a certain value. LTN154XA LTN156AT01 LTN156AT02

7) To adapt the whole process of rejection of depolarizing pulse depolarization dependent loading method

Characteristic of this method is that the whole process to a timely charge increases the discharge pulse depolarization, the discharge pulse after the restoration of the load current is conducted to detect the effect of polarization, to a certain result, then return to the charge polarization depolarization or discharge again, until the effect of depolarization required before the charge, then the whole process of adaptation to extreme measures. This scheme can effectively suppress the amount of precipitation of gas in a very small value.

3 method of battery charging for the ideal

Since 1859 there has been the battery several times, improving the battery has been in many sectors a wide range of applications. However, as people recognize the limitations of battery power system, recharging the battery was followed by the former regime of charging, the battery charging time is long. Therefore, the battery is not practical to use, can not adapt to rapid changes in economic construction and the construction of national defense. LTN156AT03 LTN160AT01 LTN160AT02

China’s traditional system of care is the lack of understanding of the law for the load case, the forced use of methods of price gouging. The shortcomings of the conventional method of pricing is to charge a long period, low efficiency, capacity outlet, sales of low battery usage, system load management, if complex. The charging system and battery behind the broad application of the existence of a certain contradiction. To this end, the field of charge, must enhance the understanding of the law office to discuss a quick and good pricing system to enable the battery to accommodate the needs of different departments and economic development the construction of national defense.

1) three-stage charging method

Charging the battery current stage constant air current method of pricing is used. Acid battery of general aviation in two stages constant current charging method used. Basic batteries of air in two steps using the method constant charge current method or load current for a step. However, this method of pricing in the intermediate stage of the load curve load current acceptance rates, loading better three-step method. vgp-bps5a vgp-bps8 vgp-bps8a

Three-step method of pricing is the two-phase flows such as pricing and a constant voltage method and the combination of courses. The beginning and end of charge at constant current, constant voltage charge to the intermediate stage. The battery with the initial burden of high intensity, constant voltage over a period of time to charge during the current down to a predetermined value, the second stage to the third stage. A three-step loading method are the following advantages: to avoid the constant voltage law began charging current volume have been too broad Houqi You current is too low, the second phase of Deng Bi load flow in the middle phase of the current Load Jie Shou Shuai Geng close to the curve. This method of pricing to reduce the fuel load, it loads all, the life of the battery.

2) a constant voltage constant current charging method

constant current charge, while charging the taking of the battery voltage, stop charging and discharging, then a current charge, followed by alternating process of loading and unloading. Discharge pulse width increases with the load in the battery, charging pulse width filled with the power increases. When the load capacity and landfill capacity is roughly equal, indicating that the battery is almost complete, immediate end to the load. vgp-bps2b vgp-bps2c vgp-bps5

This equipment has been charging local, its work process is in phase alternating current contactors, transformers and thyristor switch in the battery. When the voltage of the battery voltage reaches the exit point, over voltage sensor detects signals. The signal to charge and discharge to the state controller will stop charging state, and published three control signals. The signal first charge control signal is off the pulse generator. The second control signal from the bias signal to start, stop charging before it is discharged by the delay timing circuit (T1-T2), the question of discharge began to pulse discharge switch opened to discharge battery discharge began and after a period of delay discharge circuit resistance (T2-T3), the question of the end of discharge pulse necessary for the discharge. Followed by indictment and the process repeated discharge until the final charge. The signal sent third discharge control to start the timer, so that the depolarization of the discharge of the first start time at the scheduled time after the end of the charge, automatic shut-off. Both of these methods is the direction of the battery improvement. China has adopted the program a lot of fast charging, performance varies considerably. Various methods of charging the battery life of different impact. Comparison of two methods in theory suitable for the requirements of battery charge. vgp-bpl2 vgp-bps2 vgp-bps2a vgp-bpl5a

The new battery put into service, you must perform regularly charge and discharge. The fee is intended to provide timely restoration of the power capacity of the electric battery storage to meet the needs of electrical equipment. The goal is to quickly fill the parameters of the battery capacity test, and promote the activation of electrode active material. Battery charge and discharge status of good or bad directly affects the electrical performance and battery life. Charging the battery current in many ways to choose the reasonable and scientific method will greatly improve the battery charging effects for maintenance. LP171W01 LP171WP3 LP171WP5

A battery charging method used

1) Method of constant current charge

The process of charging the charge current remains the same, called the constant current charging method, method of constant current charging or running other method of loading. The process of charging the battery voltage is gradually increased the load current gradually decreased to maintain the load current will not increase due to the battery voltage decreases, the charge voltage should be gradually increased to maintain flow charge remains unchanged, which for loading devices require a higher degree of automation in general simple charging device can not meet the requirements of the load current constant. Constant current method of pricing, the maximum permissible battery current situation, the hour plus expenses load current, can be shortened. If from time to consider using this method advantageous. However, late fees, if the load current is always the same, this time because most of the current used for electrolysis of water, boiling the electrolyte is too much like bubbles, which only consumes energy and easy to make a large number of outboard active substances, the temperature was too high, resulting from plate bending capacity decreased rapidly and early retirement. Therefore, this pricing method is rarely used. LP171WP6 LP171WX2 LT141X7

Method 2) the constant voltage charging

During loading, the load voltage remains the same, called the constant voltage charging method, called constant voltage method or the method of equal pressure. As tension continued until the end, and always maintains a certain voltage, the charging current when charging starts fairly tall, much higher than the current value of normal load. However, with the load to the voltage across the battery increases gradually with decreasing load current. When the voltage across the battery voltage and load are equal, the charge current to minimize or even zero. So, using the method of constant voltage charging has the advantage to avoid late fees, charging excessive current caused by the loss of plate active material and energy loss. But the downside is that at the beginning of the load, the load current is too large, the electrode active material removal volume change quickly and affects the strength of the active substance, with the loss. late charges in the charge current is low, so the plate can not blame the depths of the active substance, forming a long-term care, which can affect battery life. Therefore, this pricing method generally applies only to non-distribution of materials or equipment load than just special occasions, such as car battery charger, 1-5 type of battery for charging a battery small load methods are used such pressure. This pressure charging the battery charging method, the required voltage supply: Battery acid of each monomer is approximately 2.4 ~ 2.8V alkaline batteries for each cell is about 1.6 ~ 2.0 V. LT150X3 LTN141W1 LTN141W3

3) A constant voltage load resistors

Constant voltage charging to remedy the shortcomings of the method used. That is, power and load resistance in series between the batteries, so that the initial charge current can be adjusted. However, the maximum load current is limited at certain times, if the conduct of the load, the battery voltage is gradually increased, the current was almost linear decay. Sometimes, using two values of resistance, about 2.4 V, the conversion of low resistance, high resistance to reduce output.

4) stage of the prosecution of these methods such as flow

Integrated constant current and constant voltage charging method, some recharge the battery with a large initial current, after a period of time using a smaller current, borne late to use a small current, which is in different stages with different currents constant current charging method, called phase constant current charging method. Internship constant current charging method can be generally divided into two stages can also be divided into several stages. LTN141X7 LTN141X8 LTN141XA

phase method of load current, as a short charge time required, the charge effec. Since the late fee to switch to smaller load current, which reduces air bubbles on the erosion of the active electrode material, reduce shedding of active material. This pricing method can extend the battery life and save energy, fully charged, it is currently used as a method of pricing. The first stage of the general battery charging current rate 10h, 20h rate of the second phase of load current. The various stages of charging time, the specific requirements of different batteries and standards are different.

5) The float charging method

Intermittent use of the battery or power outage that when used in the battery, load type floating charge. special occasions for the use of the battery fixed float charging methods are commonly used to charge the battery. The main advantages of the floating charge method is to reduce the rate of degassing of the battery and prevents over the load, and because the battery in parallel with the DC power supply, electrical equipment, a great wave electricity, the battery output current instant, which helps stabilizes voltage, the normal use of electrical equipment. Float charging method at the expense of load imbalance of individual battery and no electric charge, so that the need for periodic equalizing charges. vgp-bps13a/b vgp-bps13b/b vgp-bps13

2 Battery Charging Method

1) the method constant charging current for a period

This approach is characterized by constant current amplitude and the cycle pulse constant current charge to the battery between the two charge pulses with a burst of depolarizing pulses to improve the battery charge acceptance. Width during loading, the load current of the battery and the pulse of the state of charge. Therefore, there is a charge pulse ring type. This method of loading with the load capacity of batteries, but if you do not increase the protective device to prevent the cooler, more load easily lead to a strong battery life on. In this pricing approach, although the loading process measures have been reinforced by a depolarization, but this depolarization fixed, difficult to meet the requirements of the entire underwriting process. vgp-bps9a vgp-bps9a/b VGP-BPS13/S

2) define the gas rate constant discharge current of the charge pulse depolarization method of loading

This pricing method is characterized by: the whole process of pricing, the amplitude of the current pulse charging the battery and degassing remain the same. The process of initial loading, the load current of the battery is slightly less than the initial acceptance of the current. In the charging process, because it reduces the battery current is unacceptable, then after a charging time of battery current to exceed the maximum acceptable, and therefore the battery solution will produce more gas, the exit rate increased significantly. At this stage, the gas detection devices to send control signals in time to force the battery will stop charging discharge short. This polarization in the battery very quickly disappear, degassing can always stay in a predetermined lower value. Currently, such programs abroad. the lack of gas detectors, little research on this approach to China. vgp-bps9 vgp-bps9/s vgp-bps9/b

In designing the communication system and construction, power of communications is recognized as the heart of grid communication systems, will directly affect the reliability and stability of communication systems. APC Inc., a U.S. survey showed that nearly 75% or more of the communication system failures are due to equipment failures caused by food. Currently, the communication system uninterruptible power supply batteries are provided either by the battery temperature is too high will inevitably affect the efficiency and battery life. Therefore, monitoring the battery temperature in real time of real meaning. B121EW03 B121EW07 B133EW01

A system composed of

Battery temperature monitoring system block diagram. Primarily the voltage, temperature and humidity, the temperature of the collection, 89S51 microcontroller, the control unit keyboard, the display circuit module communication module. The system can complete the 6 groups, six or more temperature measuring communication battery, an engine room driving environmental measures (temperature, humidity measurement), 2-2 lanes and DC AC voltage measurements, the transfer of data from more than 200 m.

2 Hardware Design

2.1 Selection microcontroller

The selection system 89S51 MCU, the single chip using the new technology 0.35. Cost reduction, improved function, compared with traditional 89C51 MCU has the following main features:

(1) have better performance have been improved prices remain virtually unchanged;

(2) the functions of ISP-line programming;

(3) the maximum operating frequency of 33 MHz, the faster speed of calculation;

(4) with duplex UART serial channel;

(5) integrated internal watchdog timer;

(6) double indicator data; B133EW03 B133EW05 B133EW06

(7) Compatibility, down 51 fully compatible with all products subseries.

2.2 The choice of temperature sensor and its connection to the SCM

DS18B20 use temperature acquisition DS18B20 single bus interface has a unique way, through the serial communication interface (I / O) directly measured the temperature output interface mode, the line port of the processor can be just a two-way communication with the DS18820 in use requires no external components, includes parasitic power, either by the parasitic power, but also by providing direct VDD allowed voltage range is 3.0 ~ 5 , 5 V, temperature / digital conversion of the existing operation about a 0.5 mA, standby current of 1μA only, the typical energy consumption of 5 mW, temperature measurement range from -55 ℃ ~ 125, in between 0 ~ 85 ℃, the error is less than 0.5 ℃, capacity support networking multi-point may be expressed in a number of buses DS18B20, allowing multi-point temperature , features negative pressure when the supply polarity reversed, the thermometer does not heat and fire, but does not work. B133XW02 B140EW01 B141EW01

access processor DS18B20 process are: DS18B20 initialize command of the operation ROM memory (including RAM and E2PROM notebook) operational command or data processing. All the processing on a single bus started from initializing the pulse of the boot sequence reset issued by the host and one or more of the response sent from the pulses of the machine. The host receives the response from the machine after the pulse, indicating a single bus device, the host can start the machine controller and controls ROM memory operation if the temperature measurement and complete DS18B20 measurement results deposited in temporary storage at high speed, and then read the result.

2.3 measures AC and DC voltage and ambient temperature and humidity

DC voltage, AC voltage and ambient temperature and humidity measurements used TLC1543, TLC1543 11-channel for 10-bit A / D converter connected to the microcontroller in Figure 3. measures for environmental room (temperature, humidity) and temperature humidity transmitter with JWS, the output signal as the standard signal 0 ~ 5 V DC voltage through resistor divider data acquisition sent directly after A / D converters, AC-Acquisition corrected by the partial pressure is also directly sent to the A / D B141EW02 B141EW03 B141EW04

2.4 shows the design of circuits

Temperature display with 6 LEDs in connection with the microcontroller of Figure 4. display module with keyboard 8279, display interface circuit and the corresponding control circuit. 8279 scan lines ~ ALC SLC in the process of digitization, the chip can be sent to the display unit of output, the contents of the online data OA0 ~ ~ OB0 OA3 and OB3 scan line by the 74HC138 decoder, that the number of LED tubes of digital bits, RP by 74LS04 and after chip driver bits for the digital control bit different driver. Meanwhile, with OA0 ~ ~ OA3 and OB3 OB0 data sent to every reader of the section corresponding digital control display 8-6 on the road, turn the LED digital tube. SN75491 SN75492 Driver and Smart, respectively, the reader section digital display tube and to ensure that six CNC on when the maximum current.

2.5 Communication Module

To meet the data transmission range over 200 m, 485 full-duplex communications with smart 75LBC180, only the chip level communication and level of the computer to complete the conversion by MAX232. MAX232 chip is designed for standard PC RS 232 serial design of interface circuits, using a single supply of +5 V. Another. RS 232 to RS 485 conversion can use a converter dedicated, as the BOK-60 or the converter ATC-160A passive. Sony VGP-BPS12 battery Sony VGP-BPS13A/S battery

3 Design Software

system monitoring battery temperature for the design of software includes the main program, external interrupt routines, display routines and so on. Figure 6 is a flowchart of main program of the system. DS18B20 call to complete the interrupt handling, and temperature measurement and temperature calculation of the value of the screen. Host 89S51 first reset pulse of the signal line all the chips are reset DS18B20, then send the functioning Skip ROM command, all DS18B20 active line and the system suspends processing switch, the completion of the change in temperature, read and so on. Completion of the external interrupt routine reads the data on the measurement of temperature, routines for LCD displays initialization and display of temperature.

4 Concluding Remarks

89S51 and based on the communication system power DS18B20 temperature control, the interface is simple, taking less microprocessor port, saves a lot of tracks and logic circuits, compared with conventional equipment has a simple structure, low cost, reliability and measuring temperature and high precision, low power consumption, the benefits of large scale application. Sony vgp-bps13a/b battery Sony vgp-bps13b/b battery