DS2762 High-Precision Li+ Battery Monitor With Alerts

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Figure 1. Block Diagram

DETAILED DESCRIPTION

The DS2762 high-precision Li+ battery monitor is a data-acquisition, information-storage, and safety-protection

device tailored for cost-sensitive battery pack applications. This low-power device integrates precise temperature,

voltage, and current measurement, nonvolatile (NV) data storage, and Li+ protection into the small footprint of

either a TSSOP package or flip-chip package. The DS2762 is a key component in applications including remaining

capacity estimation, safety monitoring, and battery-specific data storage.

Through its 1-Wire interface, the DS2762 gives the host system read/write access to status and control registers,

instrumentation registers, and general-purpose data storage. Each device has a unique factory-programmed 64-bit

net address that allows it to be individually addressed by the host system, supporting multibattery operation.

The DS2762 is capable of performing temperature, voltage, and current measurement to a resolution sufficient to

support process monitoring applications such as battery charge control, remaining capacity estimation, and safety

monitoring. Temperature is measured using an on-chip sensor, eliminating the need for a separate thermistor.

Bidirectional current measurement and accumulation are accomplished using either an internal 25m

W sense

resistor or an external device. The DS2762 also features a programmable I/O pin that allows the host system to

sense and control other electronics in the pack, including switches, vibration motors, speakers, and LEDs. This pin

may also be used to alert the host when preset accumulated current or temperature limits are exceeded.

Three types of memory are provided on the DS2762 for battery information storage: EEPROM, lockable EEPROM,

and SRAM. EEPROM memory saves important battery data in true NV memory that is unaffected by severe battery

depletion, accidental shorts, or ESD events. Lockable EEPROM becomes ROM when locked to provide additional

security for unchanging battery data. SRAM provides inexpensive storage for temporary data.

1-Wire

INTERFACE

AND

ADDRESS

THERMAL

SENSE

MUX

VOLTAGE

REFERENCE

ADC

REGISTERS AND

USER MEMORY

25m

W

DQ

CHIP GROUND

+

-

LOCKABLE EEPROM

SRAM

TEMPERATURE

VOLTAGE

CURRENT

ACCUM. CURRENT

STATUS/CONTROL

Li+ PROTECTION

IS1

IS2

SNS

IS2

IS1

CC

DC

PLS

PS

PIO

TIMEBASE

INTERNAL SENSE RESISTOR

CONFIGURATION ONLY

DS2762