| 摘要 |
PROBLEM TO BE SOLVED: To provide a re-drive circuit of a brushless DC single-phase motor, which enables cost reduction and can regulate control input voltages of power supply side switching devices over a wide range, particularly in the direction of increasing, and further in, easy manner. SOLUTION: This re-drive circuit has four switching devices PF1-PF4 of which an H-bridge is composed with a motor coil L1 in its middle part and drives a drive circuit of a brushless DC single-phase motor, which needs a control voltage exceeding a power supply voltage, when the power supply side switching devices PF1 and PF2 are turned on, so as to make the speed of the motor controllable, by changing the duty ratio of the control voltage. A circuit unit, which generates pulse signals for the control of the respective switching devices PF1-PF4 is composed of a low-cost logic circuit 17. Drive circuits 19 and 22, which receive step-up voltages and amplify control pulse signals for power supply side switching devices to levels exceeding the power supply voltage and supply the amplified step-up voltages to the control input terminals of the power supply side switching devices, are provided separately from peripheral circuits and improve the flexibility of regulation of the amplification levels. |
