| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a malfunction that two switching elements are turned on at the same time by lowering an output impedance and holding the impedance low when on/off driving signals for the switching elements change from High to Low. SOLUTION: A first and a second driving section 14, 15 receive on and off signals alternately from a controlling circuit 2 and then alternately drive a first and a second switching element 5, 6. The controlling circuit 2 detects the voltage to be applied to a load 11 and then changes the oscillation conditions so that the voltage may be constant. When one of the switching elements 5, 6 turns on, the switching element is so controlled that the impedance at an input terminal may be small. By this method, the input terminal voltages of the switching elements 5, 6 are raised and thereby the two switching elements 5, 6 are turned on at the same time and then once-through current is allowed to flow and, as a result, the switching elements are prevented from being destroyed. |
