LED LIGHTING APPARATUS

• US 20110285307A1
• Filed: 05/16/2011
• Published: 11/24/2011
• Est. Priority Date: 05/24/2010
• Status: Active Grant

• Current Assignee: Sanken Electric Company Limited
• Original Assignee: Sanken Electric Company Limited
• Inventors: Yoshinaga, Mitsutomo, KIMURA, Kengo
• Granted Patent: US 8,456,108 B2
• Time in Patent Office: Days
• US Class Current: 315/250
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/385 using flyback topology

Abstract

An LED lighting apparatus includes a triac dimmer 3, a series circuit connected to the triac dimmer and including a primary winding P of a switching transformer T and a switching element Q1, the switching transformer having a plurality of windings, a controller 14 of the switching element, a rectifying-smoothing circuit of a voltage of a secondary winding S of the switching transformer, LEDs 1a to 1n connected to an output of the rectifying-smoothing circuit, a current detector 7 detecting a current of the, a voltage detector 11 configured to output a voltage detection signal of a voltage generated at one of the secondary winding when the first rectifying element is ON, the voltage at the secondary winding being proportional to the phase-controlled AC voltage, and an amplifier 13 amplifying a signal that is based on the current detection signal and voltage detection signal for the controller.

Claims

1. An LED lighting apparatus comprising:

a triac dimmer configured to phase-control an AC input voltage at a given phase ratio and output a phase-controlled AC voltage;

a series circuit connected to the triac dimmer and including a primary winding of a switching transformer and a switching element, the switching transformer having a plurality of windings;

a controller configured to control ON/OFF of the switching element;

a rectifying-smoothing circuit having a first rectifying element and a first smoothing element and configured to rectify and smooth a voltage generated by a secondary winding of the switching transformer;

LEDs connected to an output of the rectifying-smoothing circuit;

a current detector configured to detect a current passing through the LEDs and output a current detection signal;

a voltage detector configured to output a voltage detection signal proportional to a phase ratio of the AC input voltage, the voltage detection signal being based on a winding voltage generating at the secondary winding of the switching transformer or n-th order winding thereof, and the n-th order winding being electromagnetically coupled with the secondary winding wherein n≧

3; and

an amplifier configured to amplify a voltage associating with the current detection signal and voltage detection signal and output the amplified voltage to the controller.

2. The LED lighting apparatus of claim 1, further comprising

a rectifying circuit having a second rectifying element and configured to rectify the voltage generated by the n-th order winding of the switching transformer.

3. The LED lighting apparatus of claim 2, wherein

the rectifying circuit has a second smoothing element configured to smooth the rectified voltage from the second rectifying element and supplies the output voltage of the second smoothing element to the controller as a power source.