Overview
The BQ25172DSGR is an integrated 800-mA linear charger designed by Texas Instruments for charging 1-cell to 6-cell NiMH batteries. It is particularly targeted at industrial and medical applications. The device features a single power output that charges the battery, and it supports system loads in parallel with the battery, provided the average system load does not prevent the battery from being fully charged within the safety timer duration. The charger operates in constant current mode and terminates the charge cycle based on a programmable timer or when the battery voltage exceeds the VOUT_OVP threshold.
Key Specifications
| Parameter | Minimum | Typical | Maximum | Unit |
|---|---|---|---|---|
| VIN Input Voltage | 3.0 | - | 18 | V |
| VOUT Output Voltage | -0.3 | - | 13 | V |
| IOUT Output Current | - | - | 0.8 | A |
| TJ Junction Temperature | -40 | - | 125 | °C |
| CIN Input Capacitor | 1 | - | - | µF |
| COUT Output Capacitor | 1 | - | - | µF |
| RTMR TMR Resistor | 3.6 kΩ | - | 36 kΩ | kΩ |
| RVSET VSET Resistor | 3.6 kΩ | - | 62 kΩ | kΩ |
| RISET ISET Resistor | 0.375 kΩ | - | 30 kΩ | kΩ |
Key Features
- Input voltage up to 30-V tolerant
- Automatic Sleep Mode for low power consumption with 350-nA battery leakage current
- Supports 1- to 6-cell NiMH batteries with intermittent charging
- External resistor programmable operation for series cell-count, charge current, and charge timer
- High accuracy: ±0.5% charge voltage accuracy and ±10% charge current accuracy
- NTC thermistor input to monitor battery temperature
- Cold and hot temperature charging disabled
- Integrated fault protection including 18-V IN overvoltage protection, VSET based OUT overvoltage protection, 1000-mA overcurrent protection, and OUT short-circuit protection
- 125°C thermal regulation and 150°C thermal shutdown protection
- Open-drain output for status and fault indication
Applications
- Fleet management and asset tracking
- Gas detectors
- Electronic point of sales (ePOS)
- Beauty and grooming devices
- Electric toothbrushes
- Pulse oximeters
- Blood glucose monitors
- Infrared thermometers
Q & A
- What is the BQ25172DSGR used for?
The BQ25172DSGR is an integrated 800-mA linear charger for 1-cell to 6-cell NiMH batteries, targeted at industrial and medical applications.
- What is the input voltage range of the BQ25172DSGR?
The input voltage range is from 3.0 V to 18 V.
- How does the BQ25172DSGR handle system loads in parallel with the battery?
The system load can be placed in parallel with the battery, provided the average system load does not prevent the battery from being fully charged within the safety timer duration.
- What are the key features of the BQ25172DSGR?
Key features include input voltage up to 30-V tolerant, automatic sleep mode, high accuracy, and integrated fault protection.
- How is the charge current and timer programmed in the BQ25172DSGR?
The charge current and timer are programmable through external resistors connected to the ISET, VSET, and TMR pins.
- What kind of fault protection does the BQ25172DSGR have?
The device includes 18-V IN overvoltage protection, VSET based OUT overvoltage protection, 1000-mA overcurrent protection, and OUT short-circuit protection.
- What is the operating temperature range of the BQ25172DSGR?
The operating temperature range is from -40°C to 125°C.
- How does the BQ25172DSGR monitor battery temperature?
The device uses an NTC thermistor input to monitor battery temperature.
- What are some common applications of the BQ25172DSGR?
Applications include fleet management, gas detectors, ePOS, beauty and grooming devices, electric toothbrushes, pulse oximeters, blood glucose monitors, and infrared thermometers.
- How does the BQ25172DSGR indicate charging status?
The device indicates the charging state on the open-drain STAT pin, which can drive an LED.
