JPS6284392U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a waveform diagram of essential parts of the same, FIG. 3 is a circuit diagram of a conventional example, and FIG. 4 is an explanatory diagram of the operation of the conventional example. CMP is a comparison circuit, M is a motor, PS is a DC power supply, SL is a reference voltage generation circuit, STW is a triangular wave oscillation circuit, SW is a switching means, and VR is a variable resistor.

Claims (1)

[Scope of utility model registration request] A switching means is inserted in series between the DC power source and the motor, and the switching means is controlled on and off by square wave pulses output from the speed control means, and the motor is controlled by adjusting the duty factor of the square wave pulses. In a motor speed control circuit that controls the rotational speed of the motor by adjusting the power supplied to the motor, the speed control means includes a triangular wave oscillation circuit that outputs a triangular wave with a constant period, a reference voltage generation circuit whose output voltage can be freely set, The reference voltage generation circuit consists of a comparison circuit that compares the output voltage of the triangular wave oscillation circuit with the output voltage of the reference voltage generation circuit and outputs a square wave pulse of the duty factor corresponding to the magnitude relationship between the two output voltages. is a motor speed control circuit that is equipped with a variable resistor, and a DC voltage is applied between both ends of the variable resistor, and the divided voltage output obtained from the sliding terminal is used as a reference voltage value.