| 摘要 |
PURPOSE: To keep free a processing circuit by a collector voltage of a switching element from influence of voltage variation by providing thereto a circuit which stops operation for a certain minute specified period after an off signal of the switching element of the positive side and negative side forming an arm. CONSTITUTION: An inverter circuit 4 consisting of positive side switching elements Q1, Q3, Q5 forming an arm and negative side switching elements Q2, Q4, Q6 forming an arm is connected to the positive side power supply line 2 and the negative side power supply line 3 of the main power supply 1. The switching elements Q2, Q4, Q6 of this inverter circuit 4 are not operated for a minute specified period, when the collector voltage has exceeded the specified value, by amplifying the signal from the PWM signal circuit 6 with a gate circuit 7 and turning off such output signal with a protection circuit 9. Thereby, even if the collector-emitter voltage has changed to a large extent, the circuit can be freed from the influence of the voltage variation. |
