Texas Instruments BQ79735B-Q1 Voltage & Isolation Resistance Monitor
Texas Instruments BQ79735B-Q1 Voltage and Isolation Resistance Monitor is used to measure the divided-down high-voltage nodes in a battery system. This monitor can measure voltage across fuses and contactors and check the isolation voltage in the Battery Junction Box (BJB) system. The BQ79735B-Q1 monitor features an isolated bi-directional daisy chain port that supports both capacitor and transformer-based isolation. This monitor provides 15 GPIOs and auxiliary inputs for HV and thermistor measurements, as well as relay control. The BQ79735B-Q1 devices are AEC-Q100 qualified for automotive applications. Typical applications include full electric, plug-in hybrid, and hybrid vehicles.
Features
- AEC-Q100 qualified -40°C to 125°C temperature grade
- 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, and charge measurement accuracy update to 0.2%
- Pack and cell sync to 64µS
- 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 cell monitors like the 18S (BQ79718)
Applications
- Full electric
- Plug-in hybrid
- Hybrid vehicles
Simplified System Diagram
Published: 2026-03-27
| Updated: 2026-04-16