STMicroelectronics reveals intelligent automotive circuit breaker

The quad-channel VNF9Q20F is the inaugural device in a new family of monolithically integrated solutions that combine ST’s advanced VIPower M0-9 MOSFET and proprietary STi2Fuse technology. Utilising patented I2t (current squared through time-to-fuse) functionality, the STi2Fuse responds within 100µs to shut off the MOSFET if excessive current is detected.

Acting as an intelligent circuit breaker, the VNF9Q20F enhances boardnet voltage stability and prevents overheating of PCB traces, connectors, and wire harnesses. While protecting against damaging overloads, ST’s new automotive power switch also features a capacitive charging mode that accommodates harmless inrush currents, enabling normal operation with highly capacitive loads.

Designed for the latest zonal electrical/electronic architectures, the VNF9Q20F is also suitable for fuse and relay replacement, ECU isolation, and managing systems active when the vehicle is parked. With 64 programmable current-limit values, the STi2Fuse allows designers to determine the overload response with high precision.

Internal features such as a 10-bit analog-to-digital converter (ADC) and fault registers provide comprehensive diagnostic information and digital current sense feedback, supporting vehicle capabilities like predictive maintenance. By delivering diagnostics through the SPI and incorporating a built-in self-test, the VNF9Q20F helps systems achieve specified safety integrity levels in accordance with ISO 26262. An embedded failsafe mode maintains operational status in case of failure or malfunction.

The VNF9Q20F is now in production, available in a 6 x 6mm QFN package, and priced at $2.850 for 1,000 pieces.