Texas Instruments bq79731B-Q1 High-Voltage Battery Pack Monitor
Texas Instruments bq79731B-Q1 High-Voltage Battery Pack Monitor can measure the divided-down high-voltage nodes in a battery system. The device can check isolation voltage and measure voltage across fuses and contactors in a battery junction box (BJB) system. The device has two integrated current-sense paths supporting a low-side shunt resistor. The Coulomb counting function is available for accurate SOC calculation. There are 15 GPIOs/auxiliary inputs that can be used for HV and thermistor measurements, and driving relays.
Four SW outputs can be used to drive MOSFET switches in the measurement path. The device can function as an interface and SPI HUB with up to eight separate SPI devices/groups. Over-current protection can be achieved autonomously using HW pins for fast protection during dangerous over-current events. The isolated bi-directional daisy chain ports support both transformer and capacitor-based isolation. The Texas Instruments bq79731B-Q1 can also communicate with the MCU over SPI and UART.
Features
- AEC-Q100 qualified -40°C to +125°C
- Functional safety compliant
- Documentation to aid ISO 26262 system design
- Systematic capability up to ASIL D
- Hardware capability up to ASIL D
- 17 single-ended voltage channels
- High voltage pack, link, charge measurement accuracy update to 0.2%
- Pack and cell VI sync to 64µS
- Two overcurrent detect comparators
- ±1% accuracy
- Selectable bi-directional thresholds
- Programmable OC
- Two independent current sense ADCs
- ±0.15% gain error drift
- Input range = ±275mV
- Integrated Coulomb counting
- 15 GPIO inputs as IO, I2C, SPI, ADC, and temp sense
- Dedicated MOSFET switch drive pins
- Intelligent SPI controller HUB
- Support multiple SPI peripheral devices
- HW pin to trigger contactor drivers and Pyro Fuse drivers
- Stackable and register map compatible with BQ7971x-Q1 cell monitors
Applications
- Full electric vehicles
- Plug-in hybrid vehicles
- Hybrid vehicles
Simplified System Diagram
