| 摘要 |
A fan speed control circuit is provided. The circuit includes a sensor, a control chip, a first integrated circuit, an integrated operational amplifier, a second integrated circuit, and a feedback comparator. The sensor senses a temperature of an electronic component. The control chip outputs a PWM signal corresponding to the temperature to a fan. The first integrated circuit and the second integrated circuit respectively generate a first equivalent voltage and a second equivalent voltage. The integrated operational amplifier amplifies the first equivalent voltage to generate an upper limit voltage and reduces the first equivalent voltage to generate a lower limit voltage. The feedback comparator compares the second equivalent voltage with the upper limit voltage and the lower limit voltage to generate a comparison value. The control chip adjusts the duty cycle of the PWM signal according to the comparison value, and outputs the adjusted PWM signal to the fan. |
