Patent ID: 8193825

Claim:
A test circuit for an electronic device comprising a liquid crystal display (LCD), the test circuit comprising: a pulse width modulator (PWM) to provide voltages to a display panel of the LCD; a plurality of feedback circuits to output feedback voltages to the PWM; a power supply to provide an operating voltage for the PWM; and a controller to output a control voltage to the feedback circuits in response to the electronic device being in a test mode, the controller comprising a trigger end; wherein, when the electronic device is in the test mode, the power supply provides the operating voltage to the controller and the controller outputs the control voltage accordingly, and the plurality of feedback circuits respectively decrease the feedback voltages according to the control voltage, such that the PWM increases the voltages output to the display panel according to the feedback voltages, and the increased voltages reach predetermined test voltages to test the electronic device; and when the electronic device is in an operating mode, the trigger end of the controller does not receive the operating voltage from the power supply, and the controller does not output the control voltage according to the trigger end.