US 7,479,738 B2Granted

Drive circuit for light emitting diode

AssigneeMacroblock, Inc.

InventorYi-Sheng Lin

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Abstract

A drive circuit for light emitting diode (LED) is provided, which is used to drive a plurality of LEDs to emit light. The LEDs are connected in series into a plurality of LED strings. The drive circuit includes a power converter, a detection circuit, and a report circuit. The power converter provides a driving voltage to the LED strings, and the detection circuit detects a string voltage of each LED string, and compares the string voltage with a default reference voltage, so as to determine whether the string voltage is different from the reference voltage (which indicates that the LED string is operated under a non-default state), and sends a detection signal to the report circuit. The report circuit receives the detection signal and outputs the control signal to the power converter, such that the power converter adjusts the driving voltage according to the control signal.

Claims15

Dependent claims

A drive circuit for light emitting diode (LED), connecting a power and driving a plurality of LEDs to emit light, wherein the LEDs are connected into a plurality of LED strings, the drive circuit comprising:

a power converter, connecting the power and converting into a driving voltage provided to the LED strings;
a detection circuit, electrically coupled to the LED strings and having at least a reference voltage, wherein the detection circuit detects a string voltage of the LED strings respectively and compares the string voltage with the reference voltage, so as to output a detection signal;
and
a report circuit, electrically coupled to the detection circuit and the power converter for receiving the detection signal and outputting a control signal to the power converter, wherein the power converter receives the control signal and adjusts the driving voltage according to the control signal,
wherein the detection circuit has a plurality of the reference voltages, and the reference voltages are corresponding to the LED strings, so as to compare with the string voltage of the detected LED string respectively.

2 more elements

Dependencies are inferred from the claim text.