Patent ID: 9654051
Date: 2017-05-16
CPC Classifications: H02J,H02P,Y02B,Y04S

Claim:
1. A control circuit comprising: a cooling fan configured to cool a data center; a power supply unit; a controller configured to generate a first pulse width modulation (PWM) signal to control the cooling fan to rotate at a first speed; a control unit configured to generate a second PWM signal to control the cooling fan to rotate at a second speed, wherein the second speed is less than the first speed; and a switch unit coupled to the controller, the control unit and the cooling fan, the switch unit configured to output the first PWM signal to the cooling fan in event the data center is in an active mode and to output the second PWM signal to the cooling fan in event the data center is in a standby mode; wherein the power supply unit is coupled to a power pin of the cooling fan, the power supply unit is also coupled to a first standby power supply and a system power supply, the system power supply is configured to supply power to the cooling fan through the power supply unit when the data center is in the active mode, and the first standby power supply is configured to supply power to the cooling fan through the power supply unit when the data center is in a standby mode.