Patent ID: 8319448
Filing Date: 2012-11-27
Classification: H05B,Y02B

Abstract:
1. A driver arrangement for light emitting diodes, the driver arrangement comprising: a high frequency PWM controller to deliver a light emitting diode feed voltage between a first output line and a ground output line, said controller having a PWM controller feedback pin, a linear current regulator coupled to said ground output line of said controller to regulate the light emitting diode feed current, said current regulator selectively couplable to a reference voltage, a connection switch selectively actuatable to connect said feedback pin of said controller to a scaled-down version of the voltage on the first output line of said controller, and a PWM control line to receive an on/off PWM control signal to selectively produce controlled light emitting diode dimming, said PWM control line coupled to said current regulator and said connection switch to selectively couple said current regulator to said reference voltage and control switching of said connection switch, whereby: in one of the on/off levels of said PWM control signal, said current regulator is configured to interrupt said light emitting diode feed current, the voltage on said ground output line of said controller is floating, and said connection switch connects said PWM controller feedback pin to said scaled-down version of the voltage on said first output line of said controller, and in the other of the on/off levels of said PWM control signal, said current regulator is coupled to said reference voltage and controls said light emitting diode feed current, said connection switch disconnects said feedback pin of said controller from said scaled-down version of the voltage on the first output line of said controller and the voltage on said ground output line of said controller is regulated.