Patent ID: 8421390

Claim:
A fan motor control device for controlling a soft start of a fan motor, comprising: a converter having a signal input terminal, a voltage source output terminal, and a control voltage output terminal, wherein the signal input terminal receives a pulse-width modulation (PWM) signal, and a control voltage is outputted via the control voltage output terminal based on the PWM signal; a starting capacitor having a first terminal and a second terminal; and a controller having a voltage source terminal, a controlled terminal, and an output terminal, the voltage source terminal being coupled to the first terminal of the starting capacitor and the voltage source output terminal of the converter, the controlled terminal being coupled to the second terminal of the starting capacitor and the control voltage output terminal of the converter, the output terminal being coupled to the fan motor; wherein for a soft start condition, the controller controls the soft start of the fan motor based on an input voltage to the controlled terminal with a magnitude of the input voltage determined by a base working voltage outputted via the voltage source terminal; wherein under an normal operating condition, the controller controls the speed of the fan motor based on the input voltage to the controlled terminal with the magnitude of the input voltage determined by the control voltage outputted by the converter.