Method for diagnosis of opened or closed state of semiconductor power relay of secure electrical supply device of e.g. full-hybrid car, involves opening switch if voltage measured on terminal and difference are lower than voltage threshold

摘要

The method involves providing a safety switch or a semiconductor power relay (9) with a pair of MOSFET power transistors (11, 12) that is mounted in series. Voltage (Vs) is measured on a common terminal (S). Difference between the voltage measurement and another voltage measurement is determined. The difference is compared with a predetermined voltage threshold. The switch is closed if the difference is higher than the predetermined voltage threshold. The switch is opened if the voltage measured on the terminal and the difference are lower than the predetermined voltage threshold. An independent claim is also included for a secure electrical supply device.