No.4（2001）21.Development of a fault detection device for AC illumination LED Lamps

Ryoichi MIYAJIMA

LEDs (Light Emitting Diode) are used in displays, indicators and signal lights. The fault detection of AC illumination LED lamps that used many LED was difficult, because many circuits were driven in parallel. This report descrives a new device that detects the fault of a part of LED circuits of the LED lamps. This device is comprises a voltage detection circuit, current detection circuit and fault determination circuit. The output of this device is expressed by the following 3 conditions.

1. Low level when the power supply is off.
2. High level when illumination is normal.
3. A Pulse when part of the LED circuit is fault.

This device makes it possible for an individual LED lamp to output a fault detection signal.

Keywords
LED, AC, Lamp, Detector, Fault, Pulse

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