CIRCUIT FOR DETECTING FAULTY DIODE

• US 20100289519A1
• Filed: 12/07/2009
• Published: 11/18/2010
• Est. Priority Date: 05/15/2009
• Status: Abandoned Application

• Current Assignee: Janus Power Electronics Co., Ltd.
• Original Assignee: ENE Technology, Inc.
• Inventors: HUANG, CHI-FENG
• Application Number:
  US12/632,126
• Publication Number:
  US 20100289519A1
• Time in Patent Office: Days
• US Class Current: 324/767
• CPC Class Codes: G01R 31/2635 Testing light-emitting diodes, laser diodes or photodiodes

Abstract

A circuit for detecting faulty diode comprises a diode having an anode connected to a voltage supply; a resistor having a first end connected to a cathode of the diode; a transistor having a drain connected to a second end of the resistor and a source that is grounded; a differential amplifier having a positive terminal connected to the drain of the transistor, a negative terminal connected to a reference voltage input terminal for receiving a reference voltage, and an output terminal connected to a gate of the transistor; and a buffer having an input terminal connected to the gate of the transistor, and a signal output terminal used to output a faulty signal.

Claims

1. A circuit for detecting faulty diode comprising:

a diode, having an anode connected to a voltage supply;

a resistor, having a first end connected to a cathode of the diode;

a transistor, having a drain connected to a second end of the resistor and a source that is grounded;

a differential amplifier, having a positive terminal connected to the drain of the transistor, a negative terminal connected to a reference voltage input terminal for receiving a reference voltage, and an output terminal connected to a gate of the transistor; and

a buffer, having an input terminal connected to a gate of the transistor, and a signal output terminal used to output a faulty signal.

2. The circuit for detecting faulty diode according to claim 1, wherein the resistor is a current limited resistor.

3. The circuit for detecting faulty diode according to claim 1, wherein the diode is a light emitting diode (LED).

4. The circuit for detecting faulty diode according to claim 1, wherein the buffer is a hysteresis buffer.

5. The circuit for detecting faulty diode according to claim 1, wherein the reference voltage is a short-testing voltage or an open-testing voltage.

6. The circuit for detecting faulty diode according to claim 5, wherein when the reference voltage is the short-testing voltage and the signal outputted by the buffer is maintained in a high level, the diode is shorted.

7. The circuit for detecting faulty diode according to claim 5, wherein when the reference voltage is the short-testing voltage and the signal outputted by the buffer is maintained in a low level, then the diode is operated in a normal situation.

8. The circuit for detecting faulty diode according to claim 5, wherein when the reference voltage is the open-testing voltage and the signal outputted by the buffer is maintained in a high level, then the diode is operated in a normal situation.

9. The circuit for detecting faulty diode according to claim 5, wherein when the reference voltage is the open-testing voltage and the signal outputted by the buffer is maintained in a low level, then the diode is opened.