Texas Instruments bq77207 Voltage & Temperature Protector

Texas Instruments bq77207 Voltage and Temperature Protector provides a range of voltage and temperature monitoring. These include overvoltage (OVP), undervoltage (UVP), open-wire (OW), and overtemperature (OT) protection for Li-ion battery pack systems. Each cell is monitored independently for overvoltage, undervoltage, and open-wire conditions. With the addition of an external NTC or PTC thermistor, the device can detect overtemperature conditions.

In the Texas Instruments bq77207, an internal delay timer is initiated upon detection of an overvoltage, undervoltage, open-wire, or overtemperature condition. Upon expiration of the delay timer, the respective output is triggered into its active state (high or low, depending on the configuration).

The overvoltage triggers the COUT pin if a fault is detected, and undervoltage triggers the DOUT pin if a fault is detected. If an overtemperature or open-wire fault is detected, both the DOUT and COUT will be triggered. The bq77207 device provides a Customer Test Mode (CTM) with significantly reduced delay time for quicker production-line testing.

Features

3-series cell to 7-series cell protection
High-accuracy overvoltage protection
- ±10mV at 25°C
- ±20mV from 0°C to 60°C
Overvoltage protection options from 3.55V to 5.1V
Undervoltage protection with options from 1.0V to 3.5V
Open-wire connection detection
Overtemperature protection using NTC or PTC
Random cell connection
Functional safety-capable
Fixed internal delay timers

Fixed detections thresholds
Fixed output drive type for each of COUT and DOUT
- Active high or active low
- Active high drive to 6V
- Open drain with ability to be pulled up externally to VDD
Low power consumption I_CC ≈ 1µA (V_CELL(ALL) < V_OV)
Low leakage current per cell input < 100nA with open-wire detection disabled
Package footprint option
- 12-pin WSON with 0.5mm lead pitch

Applications

Protection for Li-ion battery packs used in
- Handheld garden tools
- Handheld power tools
- Cordless vacuum cleaners
- UPS battery backup
- Light electric vehicles (eBike, eScooter, pedal-assist bicycles)