US Patent No. 10,219,348

LED FAULT DETECTION CIRCUIT AND LED CONTROL CIRCUIT USING THE SAME


Patent No. 10,219,348
Issue Date February 26, 2019
Title Led Fault Detection Circuit And Led Control Circuit Using The Same
Inventorship Jui-Chu Chung, Hsinchu (TW)
Assignee ANPEC ELECTRONICS CORPORATION, Hsinchu (TW)

Claim of US Patent No. 10,219,348

1. A light-emitting diode (LED) fault detection circuit, coupled between an LED string and an LED driving circuit, comprising:a current source, providing a first current;
a detection resistor, wherein a first end of the detection resistor is coupled to a node between the LED string and the LED driving circuit, and a second end of the detection resistor is coupled to the current source; and
a first circuit, coupled to the current source and the detection resistor;
wherein after the LED string is driven by the LED driving circuit, a detection current flows through the detection resistor, the first circuit generates a fault detection signal according to the sum of the first current and the detection current, and the LED driving circuit stops driving or continues to drive the LED string according to the fault detection signal;
wherein when at least one LED of the LED string forms a short circuit, a fault detection current generated by the first circuit is larger than a first preset current, and when the fault detection current is larger than or equal to a second preset current, the LED driving circuit stops driving the LED string according to the fault detection signal; and
wherein the second preset current is larger than the first preset current.