| 摘要 |
A backlight LED drive circuit 20 includes a step-up DC/DC converter 22 for stepping up a DC power voltage based on a PWM signal and supplying the voltage to the anode of an LED device 12c, a voltage detector 24 for detecting a feedback voltage FBV based on a voltage at a terminal 22b coupled to the cathode of the LED device, a PWM control circuit 26 for outputting a PWM signal to the step-up DC/DC converter 22 so that the feedback voltage FBV may become a predetermined voltage, and a PWM stop circuit 28 for stopping the PWM signal when the feedback voltage FBV is below a second predetermined voltage set smaller than the predetermined voltage. Thereby, such backlight LED drive circuit causes no troubles even when terminal to which the LED device is connected is rendered open. |
