TI BQ25172DSGR

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.

• 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

• Fleet management, asset tracking
• Gas detector
• Electronic point of sales (ePOS)
• Beauty and grooming
• Electric toothbrush
• Pulse oximeter
• Blood glucose monitor
• Infrared thermometer