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US 2014/0111104 A1Published application
Light-emitting device circuit and method of operating thereof
AssigneeEpistar Corporation
InventorsHsin-Mao Liu, Zong-Xi Chen
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Abstract
The light-emitting device disclosed herein comprises a step down circuit and a current limit device, wherein the step down circuit prevents the current signal provided to the light-emitting device larger than the rating current value of the light-emitting device. Moreover, the current limit device only limits current signal while the power supply surges. The two stages protect circuit turn less power to heat.
Claims14
A light-emitting device circuit, comprising:
- a step down circuit having an alternating current;
- a rectifier electrically connected to the step down circuit for rectifying the alternating current;
- a light emitting device electrically connected to the rectifier and having a rating current value and an ideal operating current value;
- and
- a current limit device electrically connected to the light emitting diode having a current limit value, wherein the current limit value is larger than the ideal operating current peak value but less than the rating current value.
2 more elements
A method of operating a light-emitting device circuit, comprising steps of
- providing a first signal having a first peak value by a step down circuit;
- providing a second signal having a second peak value by rectifying the first signal;
- providing a light emitting device having an ideal operating current with a third peak value;
- operating the light emitting device with the second signal, wherein the light emitting device further comprises a rating current value;
- providing a current limit device having a current limit value which is larger than the third peak value;
- and
- converting the second peak value and the first peak value to be not greater than the current limit value only when any of the first peak value or the second peak value is larger than the current limit value, wherein the first peak value and the current limit value are both not greater than the rating current value.
4 more elements
Dependencies are inferred from the claim text.