AC LED circuit with standard dimmer compatibility
A lighting system and a circuit for a solid state lighting apparatus are provided. The circuit includes an AC power source, an AC TRIAC dimmer, a plurality of light emitting diodes (LEDs), a bridge rectifier for providing a rectified AC waveform, and at least one capacitor for reducing flicker in the LEDs, and a plurality of LEDs with lower forward voltage connected to a static dimming bleeder or bleeder circuit for providing holding current to the triac of a dimmer circuit to increase the overall efficiency of the lighting system without dynamic control of the bleeder circuit. In some embodiments, the circuit includes a plurality of current sinks used for setting and maintaining a current to the main LEDs and to establish a stable bleeder current.
1. A circuit for solid state lighting apparatus comprising:
an AC power source;
a TRIAC dimmer;
a first plurality of light emitting diodes (LEDs);
a bridge rectifier for providing a rectified AC waveform;
at least one capacitor for reducing flicker in the LEDs;
a dimming bleeder;
a plurality of supplemental current sinks;
a plurality of resistors coupled to the plurality of supplemental current sinks to generate variable resistive load; and
a second plurality of LEDs connected in series to the dimming bleeder;
wherein the dimming bleeder and the second plurality of LEDs maintain a load on the TRIAC dimmer when an output voltage from the bridge rectifier drops below a voltage to turn on one or more of the first plurality of LEDs, and wherein the plurality of supplemental sinks augment the overall resistance of the circuit to maintain constant current through the first plurality of LEDs.
2. The circuit of claim 1 , wherein the first plurality of LEDs have a first color temperature and the second plurality of LEDs have a second color temperature that is different from the first color temperature.
3. The circuit of claim 1 , wherein the first plurality LEDs have a first color and the second plurality of LEDs have a second color that is different from the first color.
4. The circuit of claim 2 , wherein the first plurality of LEDs are turned off and the second plurality of LEDs are turned on to provide a color temperature substantially similar to the second color temperature.
5. The circuit of claim 2 , wherein the first plurality of LEDs are turned on and the second plurality of LEDs are turned on off to provide a color temperature substantially similar to the first color temperature.
6. The circuit of claim 2 , wherein the AC waveform has an input voltage between 0 V and 277 V.