New Battery Choice

Using knowledge of the impedance of the battery, to achieve accurate load and temperature compensation. The most important is that the parameters of the battery through dynamic learning, those measures in the life of the battery can be measured with precision over power. Coulomb counting method used alone, or the battery voltage is compared with the applicable law, impedance technologically to the extent of remaining battery capacity has become more outstanding. B154PW01 B154PW02 V.0 B154SW01

 

He is running the process, the need to continue to maintain the impedance of the battery (Rbat) and depth of discharge (DOD) and the relationship between the temperatures of the function of maintaining database form. Understanding what happened in different conditions will determine when the operation or use of these forms must be updated. Meter, the non-volatile memory that there are many definitions of charge, discharge, after releasing the load, discharge and other state after the relaxation of current threshold. After the charge or stop the flow stopped the relaxation time “to stabilize the voltage of the battery.

 

handheld before starting the open circuit voltage by measuring the battery (VCA), then with the OCV (DOD, T) to compare table method to determine the state of battery charge specific. When the handheld is active, and access to the load, then started the current method based on counting points Coulomb. Coulomb cons load by measuring the amount and form part of continuously calculate the value SOC. B156XW01 V.0 B156XW02 B170PW01

 

The total capacity of QMAX can load or unload when the battery voltage before and after the change is small enough, in a state of complete relaxation of two OCV readings calculated.

 

Rbat (DOD, T) table in the discharging process is continually updated. Computers used to calculate the table in the load current and temperature conditions, when the voltage at the end of his mandate. The overall impedance of the battery with the battery charge and discharge cycles of aging and the increase.

 

With the impedance information of the battery, use read-only program instructions include memory (inthefirmware) simulation algorithm for determining the voltage remaining capacity (RM). Simulation algorithm first calculates the present value SOCstart, then calculated the same load current, and the value of SOC decrease in future as the battery voltage. When simulating the battery voltage VBAT (SOCI, T) of the voltage at the battery terminals (3.OV typical value), the acquisition and the voltage corresponding to values of SOC and scored Socfinal. B170PW02 B170PW03 CLAA154WA01

 

Impedance Track battery gas gauge single test results

 

Track circuit impedance single lithium-ion battery in Figure 2. BAT2 PIN input by measuring the battery voltage differential signal, via the Coulomb counter input (PRS and NRS) followed the current. The system uses gas gauge single communications port SDQ SOC and duration of operation is near the end (Run-Time-to-empty) and other information.

 

Even in the case of load variations, IT gauges can accurately predict the remaining battery power. For example, digital cameras at different way of working, the battery is different. Figure shows how he gauges to accurately predict the remaining capacity of the battery. Remaining error rate prediction is less than 1%. And, because the battery to predict remaining battery impedance and the effect of aging can be updated in real time, so that the battery can maintain for the duration of this small error. Dell Vostro 1014 battery Dell Vostro 1015 battery

 

Impedance of the battery gas gauge integrated method of counting algorithm and Coulomb stress related, but to achieve a more accurate monitor of the battery. In the relaxed state can get an accurate measurement of the OCV SOC value. Like all self-discharge of the battery OCV decreased during the reaction out of him, without the need for a correction of self-discharge. When the device is in active mode and the access charge to begin the implementation of the current method of counting points-based Coulomb. impedance of the battery measured by the updates in real time. Dell Studio 1737 battery Dell Vostro 1000 battery

System of energy management to meet the greatest challenge is how to extend the operating time of battery. In addition to the search for new energy density and power system designers looking to use the battery as efficiently as possible methods. Most of them focus on improving the DC / DC conversion efficiency, prolonging battery life, but often neglected and the efficiency of power conversion and battery capacity as important as issues gas gauge the accuracy of the battery. If the battery gauges to monitor the margin of error of ± 10% in order to avoid loss of critical data, the system can only use 90% of battery power. This equates to a loss of 10% of the capacity of the battery or battery life. B150XG02 B154EW01 B154EW02

 

management wireless account access, data processing and medical monitoring and many other mobile applications remaining capacity of the battery requirements of high accuracy to avoid a sudden closure due to run out of power. However, to ensure that the life cycle of the battery, the overheated state or use excess electricity load measurement accuracy is difficult, end users, and even some system designers have underestimated this. Mainly because of the battery can power and firing speed, temperature, aging and self-discharge characteristics of a function. Develop an algorithm to accurately define the characteristics of the battery self-discharge and the effects of aging on the capacity of the battery are almost impossible to achieve. In addition, the fuel gauges traditional battery requires the battery is fully charged and discharged completely current capacity of the battery, which rarely occur in real applications, resulting in greater measurement error. Therefore, the battery is difficult to accurately predict the operating cycle, the remaining battery capacity and time.

 

This article describes how to use the latest technology 11 for measuring battery impedance tracking technology to solve the above problems, the document also cites a unique solution of the lithium-ion batteries for a case of simple design. B154EW04 V.7 B154EW04 V.1 B154EW03

 

The existing electricity problems in measurement techniques

 

Down lithium-ion battery is the main reason for the battery duration of the film, this common misunderstanding. In fact, continued to increase the impedance of the battery (not decrease battery capacity), which led to the battery life, system shutdown ahead of a key. 100 in the battery charge and discharge cycles or so, the capacity of the battery is only down 5%, while the DC impedance of the battery increases to double or triple the rate of factor party. The aging of the increase in impedance of the battery is a direct consequence of the fall of internal pressure caused by the load current increases. A result, aging batteries to minimum operating voltage (or the termination voltage) of the time much sooner than the new battery.

 

Traditional battery measurement technique is mainly based on the voltage and coulomb counting algorithm development, and measure the performance limitations are obvious. Since low cost and simple, based on the method of voltage measurement is widely used in mobile phones and other handheld devices, but using the impedance of the battery over time will change and affect the accuracy of the method. B154EW04 B154EW08 B154EW08 V.1

 

The loading conditions and temperature changes can cause the battery capacity of up to 50% discount. Most end users in the use of real gas gauge is not equipped with handheld devices, have experienced a sudden battery drain caused by the closure of the situation. On the other hand, Coulomb counting method adopted a different method of continuously thanks to the integral of Coulomb to calculate the amount consumed and the charge state of charge (SOC), while the total capacity is known therefore, the remaining capacity can be valuable. The disadvantage of this approach is difficult to accurately quantify (model) of the discharge power, and because the method does not perform a periodic calibration cycle, resulting in measurement error over time is increasing. These algorithms do not solve the change in impedance of the battery. To avoid a sudden stop, the designer must be an early termination of the system, to retain more energy, which leads to much electricity is wasted. Dell Vostro 1320 battery Dell Vostro 1500 battery

 

The chemical capacity of the battery impedance and dynamic control

 

Impedance Track (IT) technology is unique, more Jingqu existing solutions because it is Jishu learning mechanism with Neng Zhi Dao Dezi address under the impedance of the battery and vacuum conditions Huaxue all Rongliang (Qmax ) occurred Bianhua aging Wen Ti. Impedance technologically to learn and use a dynamic simulation algorithm to track the characteristics of the battery, that is, the process actually used in the battery, the first measurement of impedance and capacitance value, then follow evolution. The use of the algorithm is complete without calibration capability regular cycle. Dell Vostro 1200 battery Dell Vostro 1310 battery

CBS0, CBS1 (Pins 10,11): Select the battery voltage balance. The PIN is entered 3 ground or VCC are related to the implementation logic low or logic high, while floating to achieve intermediate threshold; Dell Latitude E6500 Screen Dell Studio 15 Screen

 

OVS0, OVS1 (Pins 12,13): overvoltage threshold Select. The inputs are three input pins, the ground or VCC are related to the implementation logic low or logic high, while floating to achieve intermediate threshold. N. C (pin 14.30): vacant and have no connection; GND (Pin 15): Ground. The minimum voltage of the battery connected to the negative terminal; V10 V00 ~ (16 ~ 26 pin): Negative voltage detector. Connected to the first section of the battery in the negative; VIN (Pin 27): Connect to the larger battery, DC (Pin 28): input PRBC. DC loading door FET control, drive to VOLCC PKP, and enable or disable load FET; SNS (Pin 29): detection of the entry. Connected to the charge and discharge FET drain. As a detection circuit reference voltage and the discharge overcurrent, AC (Pin 31): control input load. DC loading door FET control, drive to VOLCC PKP, and enable or disable load FET; PKP (Pin 32): positive battery. PKP voltage is used to detect the release of the accessory charger or the protection of the state. Dell Studio 1535 Screen Dell Studio 1536 Screen

 

Three design applications DS2726

Typical application circuit DS2726, based on a simple design change can make use of DS2726 Li + battery monitor to withstand a negative voltage, the charger when the battery polarity reverses.

 

3.1 Protection of PKP pin

PKP pin easily exposed to the charging voltage contrast, the typical application circuit, the pin was connected to a Schottky diode, to avoid shock induction (product flow), so that the pin is pulled-in soil. The only change is to improve the impedance PKP, which limits the current through the Schottky diode. October 1942 battery charger V. 60 V Schottky diodes with Vf = 0.45 V RPKP voltage: -42 V-(-0.45 V) =- 41.55 V Assuming that 250 mW of resistance were: 250 mW = (-41.55 V) 2/RPKP, which RPKP = 6.905 kΩ. Dell Studio 1537 Screen Dell Studio 17 Screen

 

3.2 Protection of the DC FET using a rheostat

CC is another negative voltage axis exposed to normal work, DC FET gate drive regulator load voltage variation PKP pin voltage to turn off-FET. PKP CC pin voltage is pulled to the following when approximately 10 V, conduction FET. Because PKP will be clamped at -0.45 V CC can not open the FET. However, the charge control FET can withstand ± 20 V gate – source voltage. If the FET gate charge controller and the source rheostat between the increase of V2, to protect the FET DC damage. If there is no V2 door – source voltage reaches about -42 V, which exceed the ratings of FET.

 

16V Varistor V2 open, clamp gate – source. The FET voltage DC: 42V-26V +16 V =-. DC voltage drop across the resistor:-26V-(-0.45V) =- 2555V. Resistance is supposed to use 250mW: 250mW = (-25.55V) 2/RCC that RCC = 1.857 kΩ.

 

DC resistance and PKP will lead to greater load FET controller on / off time increases, so the linear region when the FET to remain open longer. The practical application of this problem is not serious because the current is limited by the charger. Dell Studio 1720 Screen Dell Studio 1735 Screen

 

3.3 SNS lever

Although the DC FET turn-off, the voltage is negative in the + PK body diode conduction. negative voltage at the SNS, SNS is the latest clip requires a Schottky diode PIN. FET Drain Voltage Protection: -42 V + O. 6V =- 41.4 V. SNS pin voltage is clamped at -0.45 V. voltage drop in the resistance SNS-41.4V-(-0.45V) =- 39.95 V Assuming that 250 mW Resistance: 250mW = (-39.95 V) 2/RCC, which, RCC = 6.384 kΩ. Compare SNS pin will absorb approximately 1μA current: 1μA × 6.384 = 6.384kΩ mV.

 

This will be the introduction of an error of over-current threshold of about 6.4 mV. If you use a high power rating, resistance can be reduced, thereby reducing the error. Note: SNS terminal RC filter time constants increase the resistance to change. Therefore, the value of the capacitor must be changed accordingly to maintain an appropriate time constant. SNS should RDOC time constant and time constant compatible with the CBC. If the time constant of these pins are incompatible, the overcurrent threshold will present additional error. Presario V2000 battery Compaq presario 1700 battery

 

4 Conclusion

DS2726 Li + protection device battery through the circuit changes, be able to reverse the charger when the battery protection. Although the design has made compromises to consider, but not the overall performance of protective devices involved. This hypothesis calculated nominal resistance 250mW. If you select the rated greater strength, can reduce resistance. Least resistance to help reduce the overcurrent threshold voltage error generated can also reduce the on / off time. It is necessary to ensure that no more than the Schottky diode current rating. Compaq Evo N600c battery Compaq Evo N610c battery