Patent ID: 8456094

Claim:
Alight emitting device open/short detection circuit, for detecting whether at least one light emitting device string is open-circuited or short-circuited, wherein each light emitting device string includes one or more light emitting devices connected in series, and each light emitting device string has a first end and a second end, the first end being coupled to a power supply circuit to supply electrical power to the light emitting devices, the light emitting device open/short detection circuit comprising: a first abnormal voltage detection circuit coupled to the second ends of the light emitting device strings, for receiving voltages at the second ends of the light emitting device strings and generating a first abnormal voltage detection signal; a first voltage setting circuit coupled to the first abnormal voltage detection circuit, for setting a first abnormal reference level; and a first determination circuit coupled to the first voltage setting circuit, when the first abnormal voltage detection signal reaches or exceeds the first abnormal reference level, the first determination circuit generates a first open/short detection signal to indicate an abnormal condition.