Patent ID: 7965096

Claim:
A circuit for detecting a faulty diode comprising: a diode, having an anode connected to a voltage supply; a first switch, having a first end connected to a cathode of the diode; a testing current source, connected to a second end of the first switch; an one-shot circuit, used to generated and transmit an output signal to a control end of the first switch; and a comparator, having two ends respectively connected to a reference voltage input terminal for receiving a reference voltage and connected to the second end of the first switch; a second switch, having a first end connected to the cathode of the diode; and a control current source, connected to a second end of the second switch; wherein when the one-shot circuit closes the first switch for a maintaining period to urge the comparator to compare the reference voltage with the voltage applied to the second end of the first switch, whereby a signal used to discriminate whether the diode is fail or not is generated and after the one-shot circuit closes the first switch for the maintaining period, the second switch is closed and the first switch is opened, whereby the control current source controls the diode.