Lighting system

Patent metadata

Field	Value
Publication number	US-9332605-B2
Application number	US-201314100382-A
Country	US
Kind code	B2
Filing date	Dec 9, 2013
Priority date	Jun 7, 2013
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

A lighting system includes a switch configured so that when the switch is in a first state, current from a supply flows to a light emitter, and when the switch is in a second state, current from the supply flows through the switch bypassing the light emitter. A capacitor in parallel with the light emitter provides current to the light emitter sufficient to cause the light emitter to emit light when the switch is in the second state.

First claim

What is claimed is:

1. A lighting system, comprising:
a plurality of light emitters arranged into a plurality of segments, the segments connected in series between a rectified alternating current (AC) power mains and ground;
each segment including a capacitor connected in parallel with at least one light emitter in the segment;
each segment including an electronic bypass switch that allows current to flow from the power mains through the light emitters in the segment and to the capacitor in the segment when the bypass switch is in a first state, and current from the power mains bypasses the light emitters and the capacitor in the segment when the bypass switch is in a second state; and
current to the light emitters in each segment is provided by the capacitor in the segment when the bypass switch is in the second state;

further comprising:
a plurality of timing control circuits, one timing control circuit for each of the plurality of light emitter segments for generating timing signals for the electronic bypass switch of one segment independent of timing control signals for the bypass switch of other light emitter segments without central control, comprising:

a logic circuit having to output states having an output coupled to the electronic bypass switch wherein a first state drives the electronic switch OFF and a second state drives electronic bypass switch ON;
a circuit for determining a voltage across the segment for driving the logic circuit to the first state when the voltage across the segment exceeds a first threshold and for driving the logic circuit to the second state when the voltage across the segment drops below a second threshold, wherein as the rectified AC power rises and falls, the electronic bypass switches of different ones of the plurality of timing control circuits turn ON and OFF as the voltage across the segments change due to the insertion or removal, by the action of the electronic bypass switches, of the series connected light emitter segments.

2. The lighting system of claim 1 , the switch control sensing a voltage at the switch controller relative to ground, the switch controller controlling the switch to be in the first state when the voltage at the switch controller exceeds the predetermined threshold.

3. The lighting system of claim 1 where the light emitters are Light Emitting Diodes.

4. The lighting system of claim 1 , each segment further comprising a diode connected so that the capacitor in the segment does not discharge through the bypass switch when the bypass switch is in the second state.

5. The lighting system of claim 1 , the switch controlled to be in the first state a plurality of times as the rectified power mains increases from zero to a peak voltage.

6. The lighting system of claim 1 , the switch controller comprising an amplifier having an input, and a resistor coupled between the input and ground, so that when current through the resistor exceeds a predetermined threshold the amplifier causes the bypass switch to be in the first state.

7. The lighting system of claim 1 wherein after an initialization period, all of the light emitters continuously emit light.

8. A method of operating a lighting system, comprising:
sensing, by a switch control circuit for each of a plurality of light emitter segments, a rectified AC voltage at the switch control circuit relative to ground;
opening, by the switch control circuit, a switch, to allow current to flow to one light emitter segment and to a capacitor, when the voltage at the switch control circuit exceeds a threshold;
closing, by the switch control circuit, the switch, bypassing the one light emitter segment and the capacitor, when the voltage at the switch control circuit is less than the threshold; and
providing current to the light emitter, by the capacitor, when the switch is closed, wherein as the rectified AC power rises and falls, the electronic bypass switches of different ones of the plurality of timing control circuits turn ON and OFF as the voltage across the segments change due to the insertion or removal, by the action of the electronic bypass switches, of the series connected light emitter segments.

9. The method of claim 8 , further comprising:
preventing, by a diode, current from the capacitor from flowing through the switch when the switch is closed.

10. The method of claim 8 , further comprising:
closing, by the switch control circuit, the switch, a plurality of times as a supply voltage increases from zero to a peak voltage.

Assignees

• Texas Instruments Inc

Inventors

• Nederbragt Irwin Rudolph
• Barrow Steven Michael
• Yin Yan
• Cambier Craig Steven

Classifications

• H05B45/48 Primary

  having LEDs organised in strings and incorporating parallel shunting devices · CPC title

• H05B33/083 Primary

  Electricity · mapped topic