Product details

Number of series cells 1, 2, 3, 4, 5, 6 Charge current (max) (A) 0.8 Vin (max) (V) 18 Cell chemistry NiMH Battery charge voltage (max) (V) 10.5 Absolute max Vin (max) (V) 30 Control topology Linear Control interface Standalone (RC-Settable) Features BAT temp thermistor monitoring (hot/cold profile), IC thermal regulation Vin (min) (V) 3 Rating Catalog Operating temperature range (°C) -40 to 125
Number of series cells 1, 2, 3, 4, 5, 6 Charge current (max) (A) 0.8 Vin (max) (V) 18 Cell chemistry NiMH Battery charge voltage (max) (V) 10.5 Absolute max Vin (max) (V) 30 Control topology Linear Control interface Standalone (RC-Settable) Features BAT temp thermistor monitoring (hot/cold profile), IC thermal regulation Vin (min) (V) 3 Rating Catalog Operating temperature range (°C) -40 to 125
WSON (DSG) 8 4 mm² 2 x 2
  • Input voltage up to 30-V tolerant
  • Automatic Sleep Mode for low power consumption
    • 350-nA battery leakage current
    • 85-µA input leakage current when charge disabled
  • Supports 1- to 6-cell NiMH with intermittent-charging
  • External resistor programmable operation
    • VSET to set NiMH series cell-count from 1s to 6s
    • ISET to set charge current from 10 mA to 800 mA
    • TMR to set charge safety timer duration from 4 hr to 22 hr
  • High accuracy
    • ±0.5% charge voltage accuracy
    • ±10% charge current accuracy
  • Charging features
    • NTC thermistor input to monitor battery temperature
    • Cold and hot temperature charging disabled
    • VOUT_OVP reduced at cool temperatures
    • TS pin for charging function control
    • Open-drain output for status and fault indication
  • Integrated fault protection
    • 18-V IN overvoltage protection
    • VSET based OUT overvoltage protection
    • 1000-mA overcurrent protection
    • 125°C thermal regulation; 150°C thermal shutdown protection
    • OUT short-circuit protection
    • VSET, ISET, TMR pins short/open protection
  • Input voltage up to 30-V tolerant
  • Automatic Sleep Mode for low power consumption
    • 350-nA battery leakage current
    • 85-µA input leakage current when charge disabled
  • Supports 1- to 6-cell NiMH with intermittent-charging
  • External resistor programmable operation
    • VSET to set NiMH series cell-count from 1s to 6s
    • ISET to set charge current from 10 mA to 800 mA
    • TMR to set charge safety timer duration from 4 hr to 22 hr
  • High accuracy
    • ±0.5% charge voltage accuracy
    • ±10% charge current accuracy
  • Charging features
    • NTC thermistor input to monitor battery temperature
    • Cold and hot temperature charging disabled
    • VOUT_OVP reduced at cool temperatures
    • TS pin for charging function control
    • Open-drain output for status and fault indication
  • Integrated fault protection
    • 18-V IN overvoltage protection
    • VSET based OUT overvoltage protection
    • 1000-mA overcurrent protection
    • 125°C thermal regulation; 150°C thermal shutdown protection
    • OUT short-circuit protection
    • VSET, ISET, TMR pins short/open protection

The BQ25172 is an integrated 800-mA linear charger for 1-cell to 6-cell NiMH batteries targeted at industrial and medical applications. The device has a single power output that charges the battery. The system load can be placed in parallel with the battery, as long as the average system load does not prevent the battery from being charged fully within the safety timer duration. When the system load is placed in parallel with the battery, the charge current is shared between the system and the battery.

The device charges NiMH cells in constant current mode only and terminates the charge cycle when the programmable timer expires or the battery voltage exceeds the VOUT_OVP threshold. In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold TREG, is exceeded.

The charger power stage and charge current sense functions are fully integrated. The charger function has high accuracy current, charge status display, and timer-based charge termination. The series cell-count, charge current, and charge timer are programmable through external resistors. Intermittent charging allows a NiMH battery to automatically recharge for a reduced timer duration once its voltage falls below the recharge threshold.

The BQ25172 is an integrated 800-mA linear charger for 1-cell to 6-cell NiMH batteries targeted at industrial and medical applications. The device has a single power output that charges the battery. The system load can be placed in parallel with the battery, as long as the average system load does not prevent the battery from being charged fully within the safety timer duration. When the system load is placed in parallel with the battery, the charge current is shared between the system and the battery.

The device charges NiMH cells in constant current mode only and terminates the charge cycle when the programmable timer expires or the battery voltage exceeds the VOUT_OVP threshold. In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold TREG, is exceeded.

The charger power stage and charge current sense functions are fully integrated. The charger function has high accuracy current, charge status display, and timer-based charge termination. The series cell-count, charge current, and charge timer are programmable through external resistors. Intermittent charging allows a NiMH battery to automatically recharge for a reduced timer duration once its voltage falls below the recharge threshold.

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Technical documentation

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Type Title Date
* Data sheet BQ25172: 800-mA Linear Battery Charger for 1- to 6-Cell NiMH Batteries datasheet PDF | HTML 01 Jun 2022
Certificate BQ25172EVM EU RoHS Declaration of Conformity (DoC) 02 Sep 2022
User guide BQ25172EVM Evaluation Module User's Guide PDF | HTML 22 Jul 2022

Design & development

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Evaluation board

BQ25172EVM — BQ25172 evaluation module for 800-mA one- to six-cell NiMH linear battery charger

The BQ25172 evaluation module (EVM) is designed to evaluate and test the various operating modes of the BQ25172 device.

User guide: PDF | HTML
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WSON (DSG) 8 View options

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