Patent ID: 7880393

Claim:
A power-saving circuit for saving electrical power, comprising: a detector adapted for detecting infrared rays in a localized area, and outputting a voltage signal indicating the infrared rays are detected or not detected; a driving circuit connected to the detector, the driving circuit configured for receiving the voltage signal from the detector and outputting a control signal, the control signal being at a first state corresponding to the voltage signal indicating that the infrared rays are detected and the control signal being at a second state corresponding to the voltage signal indicating that the infrared rays are not detected; and a switch module connected to the driving circuit, the switch module configured for converting a pulsating direct current (DC) voltage received by the switch module to a stable DC voltage when the switch module receives the control signal at the first state, and not outputting the stable DC voltage when the switch module receives the control signal at the second state, when the infrared rays are detected in the localized area, the voltage signal outputted from the detector is at a high level; when no infrared rays are detected in the localized area, the voltage signal outputted from the detector is at a low level, the driving circuit comprises a first transistor and a second transistor, a base of the second transistor is connected to a collector of the first transistor; when the base of the first transistor receives the low level voltage signal, the first transistor is turned off, the second transistor is turned on, and the first state of the control signal outputted from the driving circuit is at a low level; when the base of the first transistor receives the high level voltage signal, the first transistor is turned on, the second transistor is turned off, and the second state of the control signal outputted from the driving circuit is disconnected.