摘要 |
PURPOSE:To effectively prevent simultaneous ON of a pair of switching elements inserted serially between terminals of a DC power source, and to prevent a decrease in its efficiency. CONSTITUTION:A collector of a transistor Q1 is connected to a positive electrode of a DC power source E, and an emitter of a transistor Q2 is connected to a negative electrode of the power source E. A first diode D1 is connected forward between the emitter of the transistor Q1 and the collector of the transistor Q2. An anode of a second diode D2 having a cathode connected to that of the diode D1, is connected to a base of the transistor T1. A load circuit 2 is inserted between a connecting point of the transistor Q1 and the diode D1 and the negative electrode of the power source E. In a normal operation, a current flows only to the diode D1. If the state in which both the transistors Q1 and Q2 simultaneously become ON, occurs, the transistor Q1 is held OFF by the function of the diode D2. |