High-power lithium battery pack BMS protection board circuit based on Hall current sensor GX950 (ACS758)

Battery management system (BMS) is an increasingly important key part of systems such as power inspection robots, electric vehicles, and large unmanned remotely operated vehicles. Existing design methods use discrete devices, which have complex circuits, occupy large PCB areas, have low reliability, and are not easily scalable. Therefore, there is an urgent need for a generalized design method to reduce circuit complexity and at the same time suitable for high-current, high-voltage, battery packs with variable number of environments.

This paper introduces a high-current BMS protection board circuit, using the GX950 (ACS758) chip for isolated measurement of the output current. the GX950 chip can be used to replace Allegro‘s high-current Hall current sensors ACS756/ACS758/ACS770/ACS772, of which the GX950 is the one that meets automotive-grade standards. Please feel free to contact us at service_jesseli@gxschip.com.

The GX950 is an open-loop, high-precision linear current sensor developed specifically for high-current detection applications. The built-in 0.1mΩ primary conductor resistance effectively reduces the heat generation of the chip to support high current detection: ±50A, ±100A, ±150A, ±200A. A unique temperature compensation circuit is integrated inside the chip to achieve good consistency over the full temperature range of -40 to 150°C. The chip has been sensitized before shipment to meet automotive standards. The chip is factory calibrated for sensitivity and quiescent (zero current) output voltage, providing ±2% typical accuracy over the full temperature range.

GX950 Product Features:

- Fast output step response time: 4μs

- Single supply: 4.5-5.5V

- 65kHz signal bandwidth

- Zero hysteresis

- Internal conductor resistance: 120uΩ

- Output Voltage 2.5V or 50% VCC

- Extremely stable static output voltage

- Operating Temperature: -40℃～125℃

- Detection range: ±50A, ±100A, ±150A, ±200A.

- Package: CB-2-3 (PFF)