| 摘要 |
PURPOSE:To prevent the damage of an element and an insulation breakdown when the output terminal of a switching power source circuit is opened by providing a voltage monitor for controlling a controller of the power source to suppress the rise of output voltage when the output voltage of the power source exceeds the voltage value at the time of driving a motor. CONSTITUTION:When a driver is operated in the state that a DC motor M is not connected, a controller 2 further rises an output voltage. When the output voltage of a switching power source circuit 1 rises higher than the voltage at the time of driving the motor, the voltage of a resistor R2 is raised. When the voltage exceeds a specific voltage set by resistors R1, R7 of a voltage monitor 5 and a shunt resistor Z1, a current IF flows to a photocoupler PC1, and the voltage of the control terminal of the controller 2 is raised. The controller 2 is operated to lower the output voltage of the circuit 1. Thus, it can prevent the output voltage of the circuit 1 from excessively rising. |
