MAX1781

Obsolete

Advanced Smart Battery-Pack Controller

Advanced Smart Battery-Pack Controller Integrates a User-Programmable Microcontroller Core, a Coulomb-Counting Fuel Gauge, a Multichannel Data-Acquisition Unit, and an SMBus™ V1.1-Compliant Master/Slave SMBus Interface

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Overview

Accurate Fuel Gauge Uses V to F Method
- < 1µV Input Offset Voltage
- < 1% Gain Accuracy
- No Calibration Required
8-bit RISC Microcontroller Core
12k Bytes of Program/Data EEPROM
64 Bytes of Byte Writeable EEPROM
264 Bytes of RAM
Watchdog Timer
ICE for Firmware Debugging
Integrated Development Environment (IDE)
- C Compiler
- Inline Assembler
Eliminates Separate Primary-Protection IC
- Individual Cell Voltage Measurements with 0.5% accuracy
- Built-In Protection MOSFET Gate Drivers
- 8% Accurate Overcurrent Protection
- Programmable Over-Current Delay Timers
SMBus v1.1-Compliant, with Master Capability
Typical Operating Current < 120µA
Typical Shutdown Current < 10nA
Integrated 32kHz Oscillator: No Crystal
Fully Integrated LDO (V_IN = 4V to 28V)

The MAX1781 smart battery-pack controller integrates a user-programmable microcontroller core, a coulomb-counting fuel gauge, a multi-channel data-acquisition unit, and an SMBus v1.1 compliant master/slave SMBus interface. The 8-bit, RISC microcontroller core has an integrated 12k bytes of user programmable EEPROM, which provides battery-pack designers with complete flexibility in developing fuel gauging and control algorithms. The MAX1781 is equipped with full ICE (in-circuit emulator) capability for efficient firmware development and debugging.

The 16-bit data-acquisition unit measures individual cell voltages, cell stack voltage, chip internal/external temperature, and two general purpose analog inputs. Individual cell voltage measurements with 0.5% accuracy and over-current protection allow the MAX1781 to eliminate a separate 1st level protection IC. Adjustable over-current thresholds and delay timers provide a flexible solution.

The integrating fuel gauge module provides a typical input offset of less than 1µV, and gain accuracy of better than 1% with no trimming required during pack manufacture. The MAX1781 has a wide 4V to 28V operating voltage range. The IC is available in a 7mm x 7mm 48-TQFN package with a maximum thickness of 0.8mm.

Applications