DS2762K_技术文档

DS2762K

Li+ Battery Monitor Evaluation Kit

www.maxim-ic.com

GENERAL DESCRIPTION

FEATURES

Cꢀ^{Demonstrates the Capabilities of the DS2762}

The DS2762K evaluation kit makes performance

evaluation, software development, and prototyping

with the DS2762 Lithium-Ion (Li+) battery monitor

easy. The evaluation board interfaces to a PC

through a DS9123 serial-port adapter and RJ-11

cable connection. The provided CD ROM contains all

related data sheets along with the evaluation

software, which can be run under any Windows®

operating system.

Li+ Battery Monitor, Including:

Temperature Measurement

Voltage Measurement

Current Measurement

Current Accumulation

Temperature and Accumulated Current

Alarms

Information Storage

The DS2762K evaluation software gives the user

complete control of all functions of the DS2762.

Separate control tabs allow the user access to all

EEPROM and RAM memory locations, all control

registers, and real-time updates of all monitored

parameters. The software also incorporates a data-

logging feature to monitor a cell over time and fuel-

gauging algorithms to improve remaining capacity

calculations based on specific cell characteristics.

Identification

Overvoltage/Undervoltage Protection

Overcurrent/Short-Circuit Protection

CꢀInterfaces to the Serial Port of a PC Running

Windows OS

INDEX

Setup and Installation

Board Connections

The evaluation board circuit is designed to provide

the DS2762 with accurate parameter measurements,

allow the DS2762 to disable charging or discharging,

and protect the DS2762 from ESD damage. Kit

demonstration boards will vary as they are improved

upon over time. For information on the demonstration

board circuits, refer to the individual board

data sheets located inside the documentation

directory on the DS2762K CD ROM.

Software Installation

Selecting the COM Port

Program Menus

Register Windows

Program Tabs

Real-Time Meters

Data Logging

User Memory

Pack Information

Fuel Gauging

Windows is a registered trademark of Microsoft Corp.

EVALUATION KIT CONTENTS

1–2 pc. TSSOP or CSP Evaluation Boards of

different varieties

PD090302

DS2762K TSSOP

1 pc. DS9123 Serial-Port Adapter

1 pc. RJ-11 Cable

1 pc. DS2762K CD containing:

DS2762K Evaluation Software

DS2762 Related Documentation

EQUIPMENT NEEDED

1) A PC running Windows OS with a CD ROM drive

and an available serial port.

2) Cables with mini-grabber-style clips or the ability

to solder directly to connection pads.

3) A Li+ battery and a power supply and/or load

circuit.

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DS2762K Li+ Battery Monitor Evaluation Kit

DS2762 INFORMATION

For more information about the DS2762, refer to the DS2762 data sheet available on our website at

www.maxim-ic.com/DS2762.

SETUP AND INSTALLATION

Board Connections

Connections to the TSSOP demonstration board are best made either by soldering directly to the pads or by using

cables with mini-grabber clips. Soldering directly to the pads best makes connections to the CSP board.

Communication to the TSSOP board can be accomplished either through the RJ-11 jack by connecting the

provided standard six conductor RJ-11 cord, or by wiring directly to the DQ and PAC- pads. In the latter case, the

size of the board can be reduced by snapping off the RJ-11 jack along the break line (see Figure 1). To use the

demonstration software, the DQ and PAC- lines must be connected to the DS9123 communication brick using

either of the two methods described.

BREAK LINE

RJ-

11

Figure 1. Communication Connections

Figures 2a and 2b show the recommended circuits to simulate charging and discharging. The Li+ cell is connected

between the BAT+ and BAT- pads. The battery charger/power supply or circuit load is connected between the

PAC+ and PAC- pads. The evaluation software can be run in either configuration as long as a cell is connected

between the BAT+ and BAT- terminals, providing a minimum of 2.5V to power the DS2762. Some board versions

also have connections for the PS and PIO pins. Refer to the data sheet for the operation of these pins. Leaving

them unconnected does not interfere with the operation of the demonstration board.

DQ

POWER

PAC+

BAT+

PAC+

BAT+

SUPPLY/

BATTERY

CHARGER

+

LOAD

BATTERY

PIO

BAT-

PS

-

BAT-

PS

-

PAC-

Figure 2a. Charging Circuit

Figure 2b. Discharging Circuit

SOFTWARE INSTALLATION

To install the DS2762K software, exit all programs currently running and insert the DS2762K software CD into your

computer’s CD ROM drive. Double click the SETUP.EXE icon and the installation process begins. Follow the

prompts to complete the installation. The DS2762K software can be uninstalled in the Add/Remove Programs tool

in the Control Panel. After the installation is complete, open the DS2762K folder and run DS2762K.EXE or select

DS2762K from the program menu. A splash screen containing information about the evaluation kit appears as the

program is being loaded. The Documentation directory also located on the CD contains all relevant data sheets

and application notes on the DS2762 and DS2762K.

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DS2762K Li+ Battery Monitor Evaluation Kit

SELECTING THE COMMUNICATION PORT

The first time the software runs, the Select Preferences window appears. In this window, select either serial port or

USB communication and the port number; then hit OK. The DS2762K software saves this port selection and

automatically uses the selection each time the program starts. To change the port later, click the Preferences

option on the menu bar, select Port Settings, and then select the appropriate port. To attempt to automatically

locate the DS9123, click the Poll Serial Ports button. Warning: Automatically polling for the DS9123 can disrupt

other devices connected to your computer’s COM ports.

MENUS

Several pull-down menu options have been provided to simplify use of the DS2762K software. Their functions are

individually detailed below.

File Menu

The File Menu allows the user to store information from a file directly into the Device Setup, Battery Data, and Fuel-

Gauging Data sections under the Pack Info Tab, or take the same Pack Information and store to a file. These

functions do not directly write or read the DS2762. It is still necessary for the user to store or recall this information

to or from the device by issuing a WRITE or READ command under the Pack Info Tab.

Registers Menu

The Registers Menu gives immediate access to all four status and function registers of the DS2762. Selecting any

of the registers will open an individual control window giving the user a description of each register bit and the

ability to read or write it. See the status register window example.

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DS2762K Li+ Battery Monitor Evaluation Kit

Status Register

The present state of all register bits is displayed immediately upon opening the register window. R/W locations

contain a selection field to allow the user to determine their state. Pressing either the APPLY or OK button in the

EEPROM Register or Special Feature Register windows will automatically update and read the corresponding

register inside the DS2762. The Protection and Status registers have default values stored in user EEPROM

addresses 0x30h and 0x31h, respectively. Their windows contain extra options to write or read these locations

independently of their registers.

Preferences Menu

The Preferences Menu allows the user to change COM port settings at any time. Edit Preferences opens the Select

Preferences window. See Selecting the communication port above.

Help Menu

Selecting the About topic from the Help Menu opens a window containing information about the current revision of

this program and Dallas Semiconductor.

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DS2762K Li+ Battery Monitor Evaluation Kit

PROGRAM TABS

All functions of the program are divided under five tabs in the main program window. Left click on the appropriate

tab to move to the desired function page. Located under the Meters tab is information on real-time updates

measured by the DS2762: voltage, current, accumulated charge, temperature, alarms, and all error flags. The Data

Log tab allows the user to store all real-time information including protection register state to a file. The Memory tab

displays the contents of every register and memory location inside the DS2762 and allows the user to alter the

data. The Pack Information tab gives the user the ability to assign a default device configuration and store that

information to the DS2762 and/or a file. The Fuel Gauging tab uses the cell characterization information stored

under Pack Info to maintain a high-accuracy-remaining capacity indicator.

Meters Tab

The Meters Screen displays the latest real-time measurements of cell voltage, temperature, current, and

accumulated charge with both analog meter readouts and digital values. The sense resistor value used to calculate

the current reading is shown in the current section. Left click on it or go to the sense resistor sub-tab under Pack

Info to change this value. The Calibrate Offset button in the current section allows the user to zero the current

measurements under the conditions of their circuit. Left clicking this button will begin the automatic calibration

procedure. Calibration should be performed while the pack is disconnected and there is no current flow. The next

32 readings will be averaged and the offset eliminated by adjusting the Current Offset Register (location 0x33h)

automatically. The process takes approximately 20 seconds.

The user can bring up the Update Current Accumulator window by left clicking the Set ACR button. This window

allows the user to enter values for the Current Accumulator Register and Rated Battery Capacity in mAH. Rated

Battery Capacity is used to determine full-scale range on the Charge Remaining Meter only. It has no affect on

device operation.

The present states of the Charge Control and Discharge Control pins are shown at the bottom left of the window.

These outputs are active low and drive two control FETs allowing charging and discharging of the cell pack. The

Charge Control pin can be controlled manually by left clicking the Disable/Enable Charging button and will be

forced high automatically by either an overvoltage or charge-overcurrent condition. The Discharge Control pin can

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DS2762K Li+ Battery Monitor Evaluation Kit

also be controlled manually with the Disable/Enable Discharging button and will be forced high automatically by

either an undervoltage or discharge-overcurrent condition. The present state of each of the four possible flag

conditions (Overvoltage, Undervoltage, Charge Overcurrent, and Discharge Overcurrent) is represented by LEDs

inside the voltage and current sections of the window. The corresponding LED will be green while the flag is in the

cleared state. If conditions cause a flag to be tripped, the LED will turn red and a button will appear that allows the

user to clear the flag provided clear conditions have been met. If conditions for clearing the flag have not been met

by the circuit, clicking the clear button will have no effect.

The bottom right side of the screen shows the alarm settings. Press the corresponding Set button to enter high and

low values for Temperature and Accumulated Current. When the temperature or accumulated current exceed any

of the alarm values, the alarm indicator is displayed. The alarm indicator is a read of the PIO bit, which doubles as

the alarm bit when enabled.

Datalog Tab

The Datalog tab allows the user to see the DS2762’s parameter measurements graphed over time. There are

separate sub-tabs for voltage, current, temperature, and accumulated charge. Each graph displays the last 500

data points collected by the DS2762K software. The sampling interval can be adjusted from as fast as possible to

15 minutes and can be adjusted from the Sampling Interval Menu at the bottom of the window. The Clear Graphs

button will clear all data from all four graphs, but does not reset the log to file function.

The Log to File sub-tab contains control information for storing all log data to an ASCII file. The default filename is

c:\DS2762K_datalog.txt, but can be modified in the filename text field. The Log Data button toggles data logging off

and on. Data will be stored at the same interval selected for updating the graphs in the tab-delimited format of

“Time<tab>Voltage<tab>Current<tab>Temperature<tab>CA<tab>Protection Register”

for easy import into a spreadsheet. The most recent 50 samples are displayed in the window for observation.

Warning: The Log Data function overwrites previous file information. Data previously stored in the file will be lost.

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DS2762K Li+ Battery Monitor Evaluation Kit

Memory Tab

The Memory Tab gives the user access to all 12 register, 32 EEPROM, and 16 SRAM bytes inside the DS2762.

They are separated into four sub-tabs for convenience. Clicking in that address’ text box and typing a new value in

hexadecimal format can modify any value. The Write button copies the entire block of data to the corresponding

location inside the DS2762 (Scratchpad RAM on the EEPROM blocks). The Read button updates the entire block’s

text boxes with data from the DS2762 (Scratchpad RAM on the EEPROM blocks). Sub-tabs displaying any

EEPROM data also have Copy and Recall buttons to allow the user to transfer the data between Scratchpad and

EEPROM memory internal to the DS2762. The Permanently Lock Block 0/1 buttons permanently store the data

currently located in that block’s EEPROM if the LOCK bit in the EEPROM register is set. Otherwise, this button

does nothing. Warning: This data can never be changed once locked. Verify your data first by issuing a Recall and

a Read.

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DS2762K Li+ Battery Monitor Evaluation Kit

Pack Information Tab

The Pack Information tab gives the pack manufacturer the ability to assign default register settings, device and

sense resistor selection, and recommended manufacturer data and fuel-gauging information.

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DS2762K Li+ Battery Monitor Evaluation Kit

The Device Select sub-tab allows the user to choose which device on the 1-Wire® bus to communicate to and

demonstrates the SWAP feature of the DS2762. Clicking on the Find DS2762 Net Addresses button begins a

SEARCH NET ADDRESS operation on the 1-Wire bus. All DS2762s found on the bus are listed in the Net

Addresses field. To communicate to any device on the bus, click on its address inside the Net Addresses field to

select it. The program will now use this device for all operations until a different DS2762 is chosen. Clicking on the

Swap to Selected DS2762 button demonstrates the features of the SWAP command, provided all devices on the

bus have both PMOD and SWEN bits enabled in their status registers. Issuing the SWAP command causes the

selected DS2762 to wake up and enable its control FETs, while simultaneously all other devices disable their

control FETs and enter sleep mode. The user can shut down all devices on the bus by selecting the “Anonymous

Net Address” of 0x0000000000000000h that is provided and issuing a SWAP command.

The Device Setup sub-tab shows the current state of all major features of the DS2762. All status indicators shown

here directly mirror their corresponding bits in the Protection, Status, and Special Feature registers. Clicking on any

of the status indicators opens the corresponding register window to allow editing. See Registers Menu above. The

selection fields on the right-hand side of the sub-tab set how the EEPROM backup bits (locations 0x30h and

0x31h) will be programmed when the DS2762 is programmed with the pack information.

The Sense Resistor Select sub-tab allows the user to correct the current measurements if a different value of

sense resistor is used. All DS2762s with an integrated sense resistor use 25mꢀs. If the sense resistor is located

externally, the user should select the external resistor radio button on this tab, then enter the value of the resistor in

mꢀs in the Sense Resistor Value field, then click the Write Sense Resistor button. The Find Sense Resistor button

opens the Find Sense Resistor window. The user can then determine the resistance by forcing a known current

and measuring the voltage drop with the DS2762. The resistance value is stored with one-fourth mꢀ resolution into

the user EEPROM of the device. The program uses this value to convert the voltage difference from the VSENS+

and VSENS- pins into milliamps. If this value does not match the value of the external resistor, current

measurements will be inaccurate.

The Battery Data and Fuel Gauging Data sub-tabs demonstrate how the pack manufacturer can use the DS2762s

EEPROM fields to store relevant pack information such as assembly date, chemistry, etc. The fuel-gauging

characterization data is used by the fuel-gauging algorithms in the software. See the Fuel Gauging Tab description.

Clicking on the Load Default Pack Info button enters example data into the information fields of the Device Setup,

Battery Data, and Fuel Gauging Data sub-tabs. To change any of this information, simply click on the desired text

field and enter the new value. Once all data is in the desired format, click on the Write DS2762 button to copy it to

the EEPROM of the DS2762. This information can also be stored to a file and recalled later using the Load/Save

Pack Info buttons.

1-Wire is a registered trademark of Dallas Semiconductor.

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DS2762K Li+ Battery Monitor Evaluation Kit

Memory Map

The memory map below shows the format in which the data is stored within the device. All static data is stored in

Block 1, while data that might need to be updated is in Block 0. The pack manufacturer can now permanently lock

Block 1 to maintain data integrity while leaving Block 0 open for access by the host processor.

MEMORY MAP OF PACK INFORMATION DATA

0x20

Fuel Gauging—Full Point at 0LC

0x21

0x22

0x23

0x24

0x25

0x26

0x27

0x28

0x29

0x2A

0x2B

0x2C

0x2D

0x2E

0x2F

0x30

0x31

0x32

0x33

0x34

0x35

0x36

0x37

0x38

0x39

0x3A

0x3B

0x3C

0x3D

0x3E

0x3F

Fuel Gauging—Full Point difference from 10LC to 0LC

Fuel Gauging—Full Point difference from 20LC to 10LC

Fuel Gauging—Full Point difference from 30LC to 20LC

Fuel Gauging—Full Point difference from 40LC to 30LC

Total Accumulated Discharge—Divided by 20 to store in 2 bytes

Fuel Gauging—Age Scalar

Fuel Gauging—Time from Break Point to Full at 0LC

Fuel Gauging—Time from Break Point to Full at 20LC

Fuel Gauging—Time from Break Point to Full at 40LC

Fuel Gauging—Time from Empty to Full at 0LC

Fuel Gauging—Time from Empty to Full at 20LC

Fuel Gauging—Time from Empty to Full at 40LC

Cell Chemistry

PMOD

Manufacturer

SWEN

CE

DE

RNAOP

IE

Fuel Gauging—Charge Estimation Break Point in mAH

Current Offset—Do not overwrite

Sense Resistor (1/4mꢀ resolution)

Date Code—2 bytes

Fuel Gauging—Standby Empty Point difference from 0LC to 10LC

Fuel Gauging—Standby Empty Point difference from 10LC to 20LC

Fuel Gauging—Standby Empty Point difference from 20LC to 30LC

Fuel Gauging—Standby Empty Point difference from 30LC to 40LC

Fuel Gauging—Active Empty Point difference from 0LC to 10LC

Fuel Gauging—Active Empty Point difference from 10LC to 20LC

Fuel Gauging—Active Empty Point difference from 20LC to 30LC

Fuel Gauging—Active Empty Point difference from 30LC to 40LC

Fuel Gauging—Active Empty Point at 40LC

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DS2762K Li+ Battery Monitor Evaluation Kit

Fuel Gauging Tab

The final program tab performs a high-accuracy calculation of remaining cell capacity using Dallas Semiconductor’s

fuel-gauging algorithms. For this feature to function properly, cell characterization data must be stored in the

DS2762’s user EEPROM. See the Pack Information section. If characterization data cannot be found, the fuel

gauge will not start, and an error message will be displayed. The Relative Capacity number represents what

percentage of cell capacity is remaining based on present algorithm inputs such as temperature, discharge rate,

etc. This value is also reflected in the analog meter. The remaining cell capacity is also displayed in terms of

milliamp-hours and Joules under Absolute Capacity and Remaining Energy, respectively.

The remaining run time is calculated using the Run Time Power Reference input from the user. Instantaneous

current measurements in the user’s application can vary greatly. By using a reference scalar instead of actual

current and voltage measurements, the program produces a stable estimation of remaining run time. The user

should enter the largest expected power draw from the device into the Run Time Power Reference field for the

most accurate estimation.

If this example were part of a fully integrated fuel-gauging system, the algorithms would need to be updated by the

host each time the cell was fully charged or discharged in order to maintain long-term accuracy. To simulate this,

the user should click the Empty or Full buttons each time the monitored pack is completely charged or discharged.

The Empty button resets the Current Accumulator to the expected empty point based on present conditions. The

Full button sets the Current Accumulator to the expected full point based on present conditions. The Learn button

resets the expected full point to the present Current Accumulator value and updates the fuel-gauging information in

the DS2762’s user EEPROM. In doing this, the algorithms “learn” from previous results and are more accurate in

the future. This tab gives an example only of fuel gauging. For more information on the process of high-accuracy

fuel gauging, refer to Dallas Semiconductor’s fuel-gauging application notes, available on our website at

www.maxim-ic.com/appnoteindex.

Maxim/Dallas Semiconductor cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim/Dallas Semiconductor product.

No circuit patent licenses are implied. Maxim/Dallas Semiconductor reserves the right to change the circuitry and specifications without notice at any time.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

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型号：	DS2762K
厂家：	ETC
描述：	Li+ Battery Monitor Evaluation Kit Li +电池监视器评估板\n 电池监视器
文件：	总11页 (文件大小：473K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

DS2762K [ETC]

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