System and method for selectively dimming an LED
View Patent ↗Embodiments of the present disclosure include an LED ballast circuit for dimming one or more LEDs using a phase controlled dimmer switch. The LED ballast circuit has a power conditioning unit which includes a substantially fixed duty cycle clock for outputting a clock cycle and a transformer configured to store energy and discharge a substantial portion of the stored energy once per clock cycle in order to power one or more LEDs.
1. A lighting fixture adapted to receive power input controlled by a phase control-based dimmer, the fixture comprising:
a power conditioning unit comprising a substantially fixed duty cycle clock for outputting a clock cycle and a transformer configured to store energy and discharge substantially all of the stored energy at least once per a predetermined number of clock cycles; and
a lighting unit comprising one or more light emitting diodes configured to receive energy released by the transformer and produce light.
2. The lighting fixture of claim 1 , wherein the transformer discharges substantially all of the stored energy once per duty cycle.
3. The lighting fixture of claim 1 , wherein the substantially fixed duty cycle is between about 0% and about 100%.
4. The lighting fixture of claim 1 , wherein the substantially fixed duty cycle is between about 35% and about 65%.
5. The lighting fixture of claim 1 , wherein the substantially fixed duty cycle is between about 40% and about 50%.
6. The lighting fixture of claim 1 , wherein the power conditioning unit is configured to imitate a resistive value.
7. The lighting fixture of claim 1 , wherein the transformer is configured to provide electrical isolation between the lighting unit and the input voltage.
8. The lighting fixture of claim 7 , wherein the power conditioning unit is comprised within an enclosure separate from the lighting unit.
9. The lighting fixture of claim 1 , wherein the lighting portion further comprises a screw-plug connection.
10. The lighting fixture of claim 1 , further comprising an over-voltage protector configured to automatically adjust the substantially fixed duty cycle to prevent damage do to a malfunction.
11. The lighting fixture of claim 1 , wherein the power conditioning unit further comprises an impedance matching resistor configured so as to be connected in series between a phase controlled dimmer and the rest of the power conditioning unit, wherein the impedance matching resistor is chosen to prevent a false trigger by the phase controlled dimmer.
12. The lighting fixture of claim 1 , further comprising a variable resistor configured to be manually adjusted in order to adjust the substantially fixed duty cycle.
13. The lighting fixture of claim 12 , wherein manual adjusting occurs during manufacture.
14. A method of dimming an LED using a phase control-based dimmer, comprising:
providing an LED;
providing an LED driver comprising a substantially fixed duty cycle clock and a transformer;
providing a phase control-based dimmer adapted to supply a power to the LED driver;
supplying power to the transformer as a function of the duty cycle so as to charge the transformer;
wherein the transformer is adapted to substantially fully discharge at least once per a predetermined number of clock cycles; and
directing at least a portion of the energy discharged from the transformer to the LED.
15. The method of claim 14 , wherein the transformer is adapted to substantially fully discharge once per duty cycle.
16. The method of claim 14 , wherein a duty cycle of the substantially fixed duty cycle clock is between about 0% and about 100%.
17. The method of claim 14 , wherein a duty cycle of the substantially fixed duty cycle clock is between about 35% and about 60%.
18. The method of claim 14 , wherein a duty cycle of the substantially fixed duty cycle clock is between about 40% and about 50%.
19. The method of claim 14 , wherein the transformer is adapted to provide electrical isolation.
20. The method of claim 14 , wherein the LED driver further comprises a screw-plug connection.
21. The method of claim 14 , further comprising adjusting the substantially fixed duty cycle to prevent damage do to a malfunction.
22. The method of claim 14 , further comprising:
providing a phase control dimmer configured to supply a power to the power conditioning unit; and
providing an impedance matching resistor connected in series between the phase control dimmer circuit and the power conditioning unit, wherein the impedance matching resistor is chosen to prevent a false trigger by the phase control dimmer.
23. The method of claim 14 , further comprising
providing a variable resistor configured to adjust the substantially fixed duty cycle;
adjusting the variable resistor to a desired duty cycle.
24. The method of claim 23 , further comprising adjusting the substantially fixed duty cycle during manufacturing.
25. A light emitting diode dimming circuit for use with a phase control dimmer switch, the light emitting diode dimmer circuit comprising:
a substantially fixed duty cycle clock for outputting a fixed clock cycle;
a transformer configured to store energy and discharge substantially all of the stored energy at least once per a predetermined number of clock cycles;
one or more light emitting diodes configured to receive at least a portion of energy released by the transformer.
26. The light emitting diode dimming circuit of claim 25 , wherein the transformer discharges substantially all of the stored energy once per each duty cycle.
27. The light emitting diode dimming circuit of claim 25 , wherein the substantially fixed duty cycle is between about 0% and about 100%.
28. The light emitting diode dimming circuit of claim 25 , wherein the substantially fixed duty cycle is between about 35% and about 65%.
29. The light emitting diode dimming circuit of claim 25 , wherein the substantially fixed duty cycle is between about 40% and about 50%.
30. The light emitting diode dimming circuit of claim 25 , wherein the transformer is configured to provide electrical isolation.
31. The light emitting diode dimming circuit of claim 25 , further comprising an over-voltage protector configured to adjust the substantially fixed duty cycle to prevent damage do to a malfunction.
32. The light emitting diode dimming circuit of claim 25 , further comprising:
a phase control dimmer configured to supply a power to the power conditioning unit; and
an impedance matching resistor connected in series between the phase control dimmer circuit and the power conditioning unit, wherein the impedance matching resistor is chosen to prevent a false trigger by the phase control dimmer.
33. The light emitting diode dimming circuit of claim 25 , further comprising a variable resistor configured to adjust the substantially fixed duty cycle.
34. A system for dimming an LED, the system comprising the light emitting diode dimming circuit of claim 25 in combination with:
a thyristor-based dimmer and an LED ballast, the LED ballast comprising the substantially-fixed duty cycle clock and the transformer;
wherein the LED ballast is operably connected between the thyristor based dimmer and the one or more light emitting diodes, wherein the LED ballast is configured to imitate a resistive load as seen by the thyristor based dimmer.
35. The system of claim 34 , wherein the transformer is configured to substantially fully discharge once per clock cycle.
36. The system of claim 34 , wherein the LED ballast comprises an impedance matching resistor.