| 摘要 |
PURPOSE:To enable to obtain a complete pause period of upper and lower transistors and to prevent the simultaneous ON of the transistors by providing an interlock circuit by a photocoupler in the final drive unit of a power transistor and containing an insensitive zone therein. CONSTITUTION:When a power transistor 13 is ON state, a voltage is supplied to a light emitting diode 27a of a photocoupler 27, a phototransistor 27b of the secondary side of a photocoupler 22 which is connected to a drive circuit of a power transistor 14 is turned ON, thereby breaking the base input of the transistor 14. When the drive signal of a power transistor B is turned OFF, a current continuously flows to the phototransistor 27b, which is then turned OFF after t1sec. The simultaneous pause period of upper and lower power transistors can be effectively provided by increasing the t1 longer than the storage time of the power transistor. |
