Making Sense of Semiconductor-Based Circuit Breakers

With any new technology, there is a tipping point when features, cost, durability, and regulatory requirements converge. This presentation explains the status and trends of semiconductor circuit breakers. Heat generation is a primary concern for AC breakers, whereas peak switching current is a focus for battery disconnects because of available heat sinking. On-resistance times chip area (RdsA) is a good indicator of performance and cost. Industry average RdsA is about half what it was 5 years ago, and the trend is to reduce by half again within the next 5 years. The SiC JFET is a clear Rds*A leader, and Rds(on) less than 5 mOhm per chip is a milestone along the way toward a practical semiconductor circuit breaker. Specialized ICs for control, gate drive, and wireless communication will probably be commercially available within a few years. A few manufacturers will supply most of the contents of SCBs, allowing for differentiation in remote control and monitoring functions.