| 摘要 |
PURPOSE: To suppress the heat generation of a motor by delaying the rise timing of a drive pulse given to the motor when the surface temperature of the motor is higher than a prescribed value and, while the rise time is delayed, switching the power supply voltage applied across the winding of the motor to a lower power supply voltage than that applied during normal drive time. CONSTITUTION: A voltage generated by dividing a reference voltage VREF through a thermister 3 and a resistor R3 is inputted to an A/D converter 2 and detects the surface temperature of a motor 4. When a signal line PHOLD becomes high, transistors Q5 and Q6 are turned on and a signal line VM supplies a drive voltage VM 12V. When the surface temperature of the motor 4 is >75 deg.C, the signal line VM actuates a timer 2. While the timer 2 is in operation, the signal line PHOLD becomes low and both transistor Q5 and Q6 are turned off. Then, the signal line VM supplies +3V to the motor 4. |
