Patent ID: 8724350

Claim:
A power supply circuit for providing a driving voltage to a load, comprising: a pulse width modulation (PWM) control circuit for outputting a pulse signal; a transformer for converting a first direct current (DC) voltage into a second DC voltage according to the pulse signal; a voltage output terminal for outputting the driving voltage based on the second DC voltage; a temperature compensation circuit comprising a temperature sensor for detecting an operation temperature of the load and correspondingly generating a detecting signal, and a feedback signal transmitter for outputting a feedback signal based on the detecting signal; wherein the PWM control circuit adjusts a duty ratio of the pulse signal according to the feedback signal outputted by the temperature compensation circuit; wherein when the detecting signal indicates that the operation temperature of the load increases, the feedback signal is an increased feedback signal triggering the PWM control circuit to decrease the duty ratio of the pulse signal, and when the detecting signal indicates that the operation temperature of the load decreases, the feedback signal is a decreased feedback signal triggering the PWM control circuit to increase the duty ratio of the pulse signal.