| 摘要 |
PROBLEM TO BE SOLVED: To reduce loss generated in a switch element of a constant voltage power supply circuit which provides a microprocessor controlling an engine with power supply voltage at high engine speed. SOLUTION: A rectifying circuit 2 for rectifying output of a magnet-type alternating-current generator 1 is constituted by a hybrid bridge circuit of a diode D1 or D3 and a thyristor Th. Output voltage Vin of the rectifying circuit 2 is inputted into the constant voltage power supply circuit 4 to be converted into constant voltage Vout, and the voltage Vout is given to the microprocessor 5A as power supply voltage. When the engine speed is below set engine speed, the thyristor Th is turned to be ON, and by making the rectifying circuit 2 perform full-wave rectifying operation, shortage of power supply voltage at low engine speed is prevented. When the engine speed exceeds the set engine speed, the thyristor Th is turned to be OFF, and by making the rectifying circuit 2 perform half-wave rectifying operation, voltage inputted into the constant voltage power supply circuit 4 is lowered to reduce the loss generated in a transistor TR1. COPYRIGHT: (C)2005,JPO&NCIPI
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