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Product details

Parameters

Number of series cells (Min) 3 Features Cell balancing, I2C support, Multi-cell support, Open-wire detection, Separate MCU requirement Vin (Max) (V) 26.4 Number of series cells (Max) 6 Operating temperature range (C) -25 to 85 Rating Catalog open-in-new Find other Battery monitors & balancers

Package | Pins | Size

TSSOP (PW) 20 42 mm² 6.5 x 6.4 VQFN (RGE) 24 16 mm² 4 x 4 open-in-new Find other Battery monitors & balancers

Features

  • Analog interface for host cell measurement
    • Cell input MUX, level shifter, and scaler
    • 1.5-/ 3.0-V low-drift, calibrated reference allows accurate analog-to-digital conversions
  • Analog interface for host current measurement
    • Variable gain current sense amplifier capable of operation with 1-mΩ sense resistor
  • Switchable thermistor bias output for host temperature measurements
  • Overcurrent comparator with dynamically adjustable threshold
    • Alerts host to potential overcurrent faults
    • Wakes up host on load connect
  • Integrated cell balancing FETs
    • Individual host control
    • 50 mA per cell balancing current
  • Supports cell sense-line open wire detection
  • Integrated 3.3-V regulator for powering micro-controller or LEDs
  • I2C interface for host communications
    • Optional packet CRC for robust operation
  • Supply voltage range from 4.2 V to 26.4 V
  • Low power consumption
    • 40 µA typical in NORMAL mode
    • 1.5 µA maximum in SLEEP mode
  • 20-pin TSSOP or 24-pin VQFN package

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Description

The BQ76925 host-controlled analog front end (AFE) is part of a complete pack monitoring, balancing, and protection system for 3-, 4-, 5-, or 6-series cell li-ion and li-polymer batteries. The BQ76925 device allows a host controller to monitor individual cell voltages, pack current and temperature easily. The Host may use this information to determine unsafe or faulty operating conditions such as overvoltage, undervoltage, overtemperature, overcurrent, cell imbalance, state of charge, and state of health conditions.

Cell input voltages are level-shifted, multiplexed, scaled, and output for measurement by a host ADC. A dedicated pin provides a low-drift calibrated reference voltage to enable accurate measurements.

The voltage across an external-sense resistor is amplified and output to a host ADC for both charge and discharge current measurements. Two gain settings enable operation with a variety of sense resistor values over a wide range of pack currents.

To enable temperature measurements by the host, the AFE provides a separate output pin for biasing an external thermistor network. This output can be switched on and off under host control to minimize power consumption.

The BQ76925 device includes a comparator with a dynamically selectable threshold for monitoring current. The comparator result is driven through an open-drain output to alert the host when the threshold is exceeded. This feature can be used to wake up the host on connection of the load, or to alert the host to a potential fault condition.

The BQ76925 device integrates cell balancing FETs that are fully controlled by the host. The balancing current is set by external resistors up to a maximum value of 50 mA. These same FETs may be utilized in conjunction with cell voltage measurements to detect an open wire on a cell sense-line.

The host communicates with the AFE through an I2C interface. A packet CRC may optionally be used to ensure robust operation. The device may be put into a low-current sleep mode through the I2C interface and awakened by pulling up the ALERT pin.

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Technical documentation

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Type Title Date
* Datasheet BQ76925 3-Series to 6-Series Cell Li-Ion and Li-Phosphate Battery Monitor (Analog Front End) datasheet (Rev. E) Apr. 21, 2020
Application notes Getting Started With the bq76925 (Rev. B) Dec. 09, 2019
User guides bq76925EVM Evaluation Module (Rev. A) Feb. 11, 2019
Technical articles How active and passive cell balancing works Oct. 05, 2016
Technical articles Big batteries? Take a walk on the (high) side Feb. 01, 2016
Technical articles Get to know your battery pack: Part 1 Sep. 28, 2015
Application notes 3~6 Cells Battery Management System Based On BQ76925+MSP430G2xx2 Mar. 20, 2014

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Hardware development

EVALUATION BOARDS Download
document-generic User guide
99
Description

The BQ76925EVM is an Evaluation Module for BQ76925, Analog Front End for 3 to 6 Series Lithium-Ion Cells. The user's guide for the bq76925EVM evaluation module can assist designers in their evaluation of the bq76925, Analog Front End for 3- to 6-Series Lithium-Ion Cells. This guide discusses setup (...)

Features
  • Evaluation module (EVM) for bq76925
  • One bq76925 and one MSP430F2122 device with associated support circuitry
  • Support for 3-to 6-series connected cells
  • bq76925 circuit is jumper configurable for internal or external 3.3-V source
  • Supports nominal 4.2-V to 26.4-V pack voltages, 30 V maximum
  • 20-A continuous (...)

Software development

FIRMWARE Download
SLUC581.ZIP (21 KB)
SUPPORT SOFTWARE Download
SLUC268.ZIP (1682 KB)

CAD/CAE symbols

Package Pins Download
TSSOP (PW) 20 View options
VQFN (RGE) 24 View options

Ordering & quality

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