| 摘要 |
1. A circuit for controlling the switching operation of a semiconductor power component (Tp) in accordance with the binary state of a switch control signal (SC), including a galvanic separation between this control signal and the component, this circuit comprising a transformer (TR) having a primary winding (EP1), and at least one secondary winding (ES1), an oscillator (T1, T2, R1, R2, EP1, ES2) supplied with a direct voltage and delivering an oscillating signal to the primary winding, a rectifier bridge (RD) at the output of the secondary winding (ES1) and a transistorized circuit (T3, T4) fed by the rectifier bridge and supplying to a control electrode of the power component either a current for rendering it conductive or a current for blocking it in accordance with the control signal, characterized in that : - a) a means is provided for applying to the oscillator and in accordance with the binary state of the control signal two different values (Va, Vb) which are not zero and which are conceived to ensure the oscillation of the oscillator and the normal voltage supply of the transistorized circuit via the rectifier bridge, the circuit being connected to the control electrode of the power component, - b) a voltage level detector (DT) is connected to the output of the rectifier bridge and controls the transistorized corcuit in order to establish either a current for rendering it conductive or a current for blocking it according to whether the voltage level at the output of the rectifier circuit corresponds to a supply of the first value (Va) or of the second value (Vb) of the supply voltage to the oscillator. |
