Patent ID: 7535740
Filing Date: 2009-05-19
Classification: H02M,H03K

Abstract:
1. A power circuit comprising: a power supply unit supplying a driving voltage to a load; an inverter unit switching the driving voltage; and a control voltage supply unit outputting a first control voltage lower than a reference voltage applied to one terminal of the inverter unit and a second control voltage higher than the reference voltage, thus controlling the inverter unit, wherein the inverter unit comprises at least one transistor having a base terminal, an emitter terminal, and a collector terminal, the reference voltage is a voltage of the emitter terminal of the transistor, and the first control voltage and the second control voltage are applied to the base terminal of the transistor, the control voltage supply unit comprises a control voltage output unit comprising a first voltage terminal for deciding the first control voltage and a second voltage terminal for deciding the second control voltage, and the control voltage supply unit comprises a voltage difference deciding unit whose cathode is connected to the emitter terminal of the transistor and whose anode is connected to the first voltage terminal, to decide a voltage difference between a voltage of the emitter terminal of the transistor and a voltage of the first voltage terminal.