1 Feature
To meet the current requirements for mobility and portability, the design of portable products used battery. When the battery using the current state of the battery is often one of concern for users, smart phones today, digital cameras have real-time display of current battery. By Maxim DS2762′s can be real-time battery voltage monitoring, current status and remaining charge the battery and the discharge parameters, and data can be stored, as long as the microcontroller for the corresponding treatment. Toshiba Satellite M55 battery Toshiba Tecra A3 battery
DS2762 chip is the company introduced a new generation of smart chip MAXIM lithium battery monitoring the data acquisition chip for storing information security in one powerful, simple hardware connection. Its main features are:
● Only one line can carry two-way data communication with the MCU.
● includes temperature sensor can be removed from the installation of block thermistor of the battery.
● On-chip ADC for battery voltage can be monitored to determine the battery charge and discharge at the end.
●Thanks to smart battery Real time recording current and the current inflow of total output.
● has two modes of current detection? A smart method 25mΩ resistance induction, and the second can be off-chip user to select the resistance detection means.
● has two power modes: the way to work and sleep. In normal mode, the DS2762 real-time monitoring of current, voltage, temperature and capacity and other parameters yet, even in standby mode, DS2762 will stop tracking of these parameters. Toshiba Tecra A4 battery Toshiba Tecra A5 battery
2 pin Function
DS2762 pin arrangement shown in Figure 1, the PIN function as follows:
CC: Charge control of foot protection;
PLS: cathode voltage customers;
DC: Pedal PRBC protection;
SNS sense resistor connection terminal;
DQ: Data entry and exit;
IS1, IS2 sensor input:;
Terminal PS: Power mode select;
VSS: Ground;
PIO: Programmable I / O terminal: defined by the user based on the need to control the external circuit;
VDD: type of battery?
VIN: Input voltage induced. Toshiba Tecra A6 battery Toshiba Tecra A7 battery
3 Structure of Storage DS2762
DS2762 EEPROM contains can be locked EEPROM, SRAM and other characteristics register, Table 1 shows the structure of the DS2762 internal memory. What is the non-volatile EEPROM with power protection down, can be used to store important information about the battery, the latch state, they can be locked EEPROM information other fixed SRAM is typically used for temporary storage of some data miners. The first deposit of data RAM and the EEPROM; fact, EEPROM information can also be copied into RAM, a mirrored relationship between the two
4 Applications
DS2762 that the basic design for the system hardware intelligent lithium in Figure 2. The system uses the resistance on the chip detection methods.
The lithium battery monitoring system to monitor the DS2762 chips 51 and the LCD module. DS2762 completed for the current state of the battery monitoring, including the battery charge and discharge current status, voltage, current, temperature and other parameters remaining power to control, but can also automatically capture data and place in the memory. FET FET1, DS2762 FET2 other form of charge and discharge protection circuit can be used for more power, power, responsible for protecting circuits against overcurrent and short. toshiba PA3191U-1BRS toshiba PA3191U-2BRS
In 8051 the battery can in accordance with the relevant user needs to read and process parameters, and then sent to the LCD module for display. As the storage of these parameters with non-volatile EEPROM, so that the system of power protection while down. Figure 2 is circuit microcontroller to control the whole central processing system, because much work can be accomplished by a single chip, greatly reducing the complexity of the system hardware.
LCD module can be used to display the user needs to know the information on the battery state, so that users can manage the information accordingly. In fact, the LCD module accepts only single chip to control and access.
As the DS2762 data communication with the MCU when a data line, therefore, must be in strict conformity with the chip to read and write requests to write programs in order to ensure that the Successful reading and writing data. Here is the chips DS2762 use to work on the battery and the voltage, current, temperature, control parameters remaining battery as the method of implementation specific. toshiba satellite m50 battery toshiba satellite m40 battery
(1) The work of monitoring the battery
To determine which type of battery used to work in the DS2762 can use registry values during the trial. SCM once every 88ms monitor voltage, and the pressure at both ends of the IS1 and IS2 (Vis-= Vis1 Vis2) electric current in the current registry. If screw is positive, indicating that the battery is charging, if Vis is negative, the battery is discharged, that is, the equipment lithium battery-powered.
(2) Battery voltage and temperature measurements
As the chip DS2762 A / D converter and digital temperature sensor, so to get the battery voltage, temperature and other parameters, has been published by CMC in blood collection DS2762, control commands temperature, and let it automatically after sampling the voltage and temperature measurements in the corresponding registers, and finally by the MCU can read the contents of the register.
(3) Monitoring the remaining capacity
The remaining battery power is important information to the user needs it, it can make use of the current accumulation value of the register to obtain. The present value of accumulation register is automatically measured by the DS2762 battery current obtained in real time, and therefore no need to control it. Usually in the battery, the value of a battery discharge, the lower value. Thus, through the MCU can read this value to obtain the remaining capacity. the remaining capacity to follow the diagram shown in Figure 4. toshiba satellite m110 battery toshiba satellite m115 battery
In the SMC on the DS2762 to operate store orders, each order must be issued before the deadlines prescribed by reset according to the first reset signal DS2762 and DS2762 wait issued a response (to see the DS2762 ready to accept or send data), then a ROM command to be used to select the DS2762 access to the bus. The program flow chart in this article, this process has been “DS2762 initialization” procedure.
In general, the accumulation register to read the current value, to avoid false readings, first check the DS2762 registers are revised. This can be achieved by the EEC-bit EEPROM registers to achieve.
5 Conclusion
This article describes the DS2762 smart handheld system for monitoring lithium battery is part of the device. The system is equipped with a powerful, easy to use, can work together with other system. With a variety of portable electronic products widely used in real-time monitoring of the battery system design has become an essential function, therefore, introduced this system has strong practicability. toshiba satellite m100 battery toshiba satellite m105 battery