Replacing the LTC2991: GX2991 8-Channel I²C Voltage, Current, and Temperature Monitor for EV Traction Battery Inspection

The traction battery of an electric vehicle is the power source of the new-energy vehicle and directly affects the vehicle‘s range, performance, and safety. It is typically composed of tens to hundreds of cells connected in series and parallel, with operating voltages spanning tens to hundreds of volts, charge/discharge currents reaching hundreds of amperes, and severe fluctuations in operating ambient temperature. Accurate monitoring of the voltage, current, and temperature of the traction battery is the foundation for ensuring EV safety and the accuracy of range estimation.

The GX2991 voltage, current, and temperature monitor chip can replace the LTC2991 pin-to-pin. Its flexible multi-channel configuration, differential current measurement capability, and remote diode temperature measurement architecture provide a highly integrated, low-component-count solution for traction battery inspection. In low-voltage auxiliary battery monitoring, module-level acquisition nodes, and large battery pack architectures with multi-chip cascading, the GX2991 can effectively reduce component count and simplify signal chain design.

The GX2991 provides an I²C serial interface. Its 8 monitors can individually measure 8 external single-ended voltages, or be paired to perform 4 differential voltage, current, or remote BJT temperature measurements, while also measuring internal temperature and the supply voltage VCC. The device, through its built-in 10 ppm/°C reference, minimizes the number of required supporting components and board area. Optional I²C addresses and function configurations allow flexible application in various systems that need to measure temperature, voltage, or current data.

GX2991 product features:

• Can measure 8 single-ended voltages or 4 differential voltages (currents) or 4 remote temperatures

• Can measure voltage, current, and temperature individually or in any combination

• Can measure the chip‘s own operating voltage and temperature

• Single-ended voltage measurement accuracy better than 0.75%, resolution 305.18 µV

• Differential voltage and current measurement accuracy better than 0.75%, resolution 19.075 V

• Remote temperature measurement accuracy better than 2.0°C, resolution 0.0625°C

• Internal temperature measurement accuracy better than 1.5°C, resolution 0.0625°C

• 14-bit ADC for voltage/current measurement

• PWM dynamic adjustment output

• 2.9 V to 5.5 V supply operating range

• I²C interface, 8 selectable addresses, up to 8 devices sharing the bus

• Internal 10 ppm/°C voltage reference

• ESD protection rating of 6 kV HBM on V1–V8 analog input pins

• Pin-to-pin replacement for LTC2991