A converter circuit includes a detecting circuit, a PWM circuit, a control circuit, a switching circuit, and a power converting circuit. The detecting circuit generates a first or a second control signal based on the voltage level of a load. The PWM circuit outputs a power control signal when receiving the first control signal, or stops operations when receiving the second control signal. The control circuit outputs a backlight-off signal when receiving the second control signal, and outputs a backlight-on signal after outputting the backlight-off signal. The switching circuit stops operations when receiving the backlight-off signal, and reactivates the PWM circuit after receiving the backlight-on signal. The power converting circuit provides the voltage for driving the load based on the power control signal.