| 摘要 |
PURPOSE:To simplify the organization of a circuit and prevent over current from flowing, by checking the detected polarities of load voltage and oscillating circuit section output, and by controlling a rest period. CONSTITUTION:An inverter circuit is composed of transistors 1-1-1-4 and free wheeling diodes 2-1-2-4, and current is fed to a load 3. In parallel with the transistors 1-2, 1-4, voltage detecting resistor 5-1-5-4 are respectively arranged, and a polarity detecting section 6 for detecting the polarity of load voltage, a rectangular wave oscillating circuit section 7, and a polarity comparing circuit section 8 are set. Then, the polarity of voltage generated on the load 3 is detected and is compared with the output polarity of the oscillating circuit section 7, and just during a period when both the polarities are different, a rest period when all switching elements are turned OFF. As a result, the discharge period of a condenser is separated from a period when the transistors are ON for charge, and over current can be prevented from flowing.
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