Patent attributes
A control circuit for fan operating comprises a drive operating circuit, a potential modulating circuit, a comparator and a switch circuit. The drive operating circuit at least has a voltage source, a drive IC, a Hall IC and a motor coil winding, the drive IC is connected with the voltage source, and the Hall IC and the motor coil winding are connected with the drive IC. The potential modulating circuit is connected with the drive IC of the drive operating circuit and has a modulating signal source to provide a PWM signal with a duty cycle. The comparator has an input end and an output end, the input end is connected with the potential modulating circuit, and potential state of the output end is determined in accordance with the duty cycle of the PWM signal. The switch circuit is connected with the drive IC of the drive operating circuit and the output end of the comparator, and operating state of the drive IC of the drive operating circuit is determined in accordance with potential state of the output end.
