Patent ID: 9562538
Date: 2017-02-07
CPC Classifications: F04D

Claim:
1. A power supply circuit for a fan, comprising: a connector comprising a speed pin, a modulation pin, a first power pin, a second power pin, and a ground pin; a control module connected to the fan to receive a speed signal of the fan and output signals corresponding to the speed signal; a speed feedback circuit connected between the speed pin of the connector and the control module to transmit the speed signal of the fan to the control module; a first power source and a second power source; and a switching module connected to the control module, wherein the switching module is connected between the first power source and the first power pin of the connector, the switching module is also connected between the second power source and the second power pin of the connector, and the switching module connects the first power source and the first power pin of the connector or the second power source and the second power pin of the connector according to the signals from the control module.