High-Power Lithium-Ion Battery Pack BMS Protection Board Circuit Based on Hall Current Sensor GX950 (ACS758)

The Battery Management System (BMS) has become an increasingly critical component in systems such as power inspection robots, electric vehicles, and large unmanned remote-controlled vehicles. Existing design methods utilize discrete components, resulting in complex circuits, large PCB footprints, low reliability, and limited scalability. Therefore, there is an urgent need for a universal design method that reduces circuit complexity while being suitable for environments with high current, high voltage, and variable battery pack configurations.

This paper introduces a high-current BMS protection board circuit that uses the GX950 (ACS758) chip for isolated measurement of output current. The GX950 chip can replace Allegro‘s high-current Hall current sensors ACS756/ACS758/ACS770/ACS772, with the GX950 being a product that meets automotive-grade standards.

The GX950 is a high-precision linear current sensor chip specifically developed for high-current detection applications. It features an internal primary conductor resistance of 0.1 mΩ, effectively reducing chip heating to support high-current detection: ±50 A, ±100 A, ±150 A, and ±200 A. It integrates a unique temperature compensation circuit to ensure consistent performance across the full temperature range of -40°C to 150°C. The chip is calibrated for sensitivity and static (zero-current) output voltage before shipment, providing typical accuracy of ±2% across the full temperature range.

GX950 Product Features:

• Fast output step response time: 4μs

• Single-supply operation: 4.5-5.5V

• 65kHz signal bandwidth

• Zero hysteresis

• Internal conductor resistance: 120 μΩ  

• Output voltage: 2.5 V or 50% VCC  

• Extremely stable static output voltage  

• Operating temperature: -40°C to 125°C  

• Detection range: ±50 A, ±100 A, ±150 A, ±200 A,  

• Package type: CB-2-3 (PFF)