STMicroelectronics VNF9Q20F automotive circuit breaker

STMicroelectronics has launched the VNF9Q20F automotive high-side power switches with proprietary intelligent fuse protection and a serial peripheral interface (SPI) for diagnostic data. The circuit breaker is designed to enhance resilience and functional safety.

The quad-channel circuit breaker is the first in a new family of monolithically integrated devices that combines ST’s VIPower M0-9 MOSFET and proprietary STi2Fuse technology. Based on patented I2t (current squared through time-to-fuse) functionality, the STi2Fuse responds within 100 µs to turn off the MOSFET if excessive current is detected.

Performing as an intelligent circuit breaker, the VNF9Q20F enhances boardnet voltage stability and prevents PCB traces, connectors and wire harnesses from overheating. While guarding against damaging overloads, the automotive power switch also has a capacitive charging mode that allows harmless inrush currents and so permits normal operation with highly capacitive loads.

Designed for zonal electrical/electronic architectures, the circuit breaker is also used for fuse and relay replacement, ECU isolation and managing systems that are active when the vehicle is parked. With 64 programmable current-limit values, the STi2Fuse also lets designers determine the overload response.

Internal features include a 10-bit analog-to-digital converter (ADC), while fault registers provide diagnostic information and digital current sense feedback to support vehicle capabilities such as predictive maintenance. By providing diagnostics through the SPI and with built-in self-test, the VNF9Q20F enables systems to meet specified safety integrity levels in accordance with ISO 26262. An embedded failsafe mode preserves operational status in the event of a failure or malfunction.

The VNF9Q20F is in production now, in a 6 x 6 mm QFN package.