Simultaneous switch=on prevention circuitry for semiconductor valves in bridge circuit - assigns control module to each valve in branch to provide control voltage of positive polarity to control electrode for conductive phase and negative for blocking

摘要

Each valve (1; 2) is assigned a control module (3; 4) which, for the conducting phase of the valve, applies a control voltage of a determined polarity (+) at the control electrode of the respective valve; and for the blocking phase of the valve applies a control voltage of the opposite polarity (-) at the control electrode of the respective valve. Conclusions are drawn regarding an orderly blocking of one of the respective valves (1) by comparing the level and the polarity of the control voltage of this valve with a desired value of selected polarity. Pulses from an HF generator (7) are transmitted to the control assembly (4) of the other valve (2) of the pair via a pulse transformer (8), so that in positive logic a control signal lying at this control assembly is released. USE/ADVANTAGE - Protection circuit preventing simultaneous switching on of semiconductor valves in branch pair of bridge circuit, which can be switched off across their control electrodes. Potential-free indication of switching position of power semiconductor.