Patent ID: 9144127
Filing Date: 2015-09-22
Classification: H05B,Y02B

Abstract:
1. An AC-powered LED light engine, coupled between a rectifier and a plurality of extrinsic LED sub-arrays, comprising: a plurality of normally closed bypass switches, each connected in parallel with a corresponding LED sub-array except for a topmost or a bottommost LED sub-array and shuttling between three switch states: ON, REGULATION, and OFF; a normally closed current regulator coupled to the normally closed bypass switches and the extrinsic LED sub-arrays, and used to regulate a highest LED current level near a peak of an extrinsic mains voltage; a plurality of switch controllers, each of the switch controllers having a first terminal, a second terminal and a third terminal; and a shared current sense and modulation unit connected to the first terminals of the switch controllers through a plurality of corresponding resistors, and wherein the first terminal and second terminal of each of the switch controllers compare a scaled-down current sense signal and an original reference voltage, or compare an original current sense signal and a scaled-up reference voltage, when the scaled-down current sense signal is below the original current sense signal, or the original current sense signal is below the scaled-up reference voltage, each of the switch controller turns a corresponding normally closed bypass switch on via the third terminal, when the scaled-down current sense signal is at the original current sense signal, or the original current sense signal is at the scaled-up reference voltage, each of the switch controller turns the corresponding normally closed bypass switch on and off via the third terminal, when the scaled-down current sense signal is above the original current sense signal, or the original current sense signal is above the scaled-up reference voltage, each of the switch controller turns the corresponding normally closed bypass switch off via the third terminal, wherein the first terminals are connected together through the corresponding resistors respectively, the original current sense signal is provided by the shared current sense and modulation unit, the scaled-down current sense signal is obtained from the original current sense signal divided by the corresponding resistors, the original reference voltage is a reference voltage of each of the switch controller, and the scaled-up reference voltage is a superimposed of the reference voltages.