Retrofit LED lighting system for replacement of fluorescent lamp
View Patent ↗A LED retrofit lamp for replacement of socket fitted CFL lamp driven by fluorescent ballast is provided. The retrofit lamp comprises a plurality of LEDS in connection with the fluorescent ballast. The circuit of the lamp comprises a bridge rectifier that converts the AC waveform into DC.
1. A retrofit LED lamp driven by a ballast, the lamp comprising:
a string of LEDs with a series resistance mounted on a metal core printed circuit board (MCPCB) plate;
a circuit comprising an anode end and a cathode end that serves as an input from the ballast;
a thermal cut off means comprising a series resistor connected with each of the input coming from the cathode end and the anode end;
a full wave bridge rectifier equipped with a first input terminal coupled to the anode end and a second input terminal coupled to the cathode end, said full wave bridge rectifier having a output connected to the string of LEDs;
wherein the said circuit is mounted on the MCPCB plate and wherein the ballast is external to the retrofit LED lamp.
2. The retrofit LED lamp of claim 1 wherein the ballast is a fluorescent ballast, or an electronic ballast, or an electromagnetic ballast.
3. The retrofit LED lamp of claim 1 wherein the MCPCB plate is fabricated from material comprising aluminum alloy or dielectric polymer.
4. The retrofit LED lamp of claim 1 wherein the full-wave bridge rectified is made of schottky diodes.
5. The retrofit LED lamp of claim 4 wherein the schottky diode compensates for the high speed waveform produced by ballast.
6. The retrofit LED lamp of claim 1 wherein an inductor is placed between the first input terminal of the full wave bridge rectifier and the cathode end.
7. The retrofit LED lamp of claim 6 wherein the inductor is coupled at the cathode end of the input.
8. The retrofit LED lamp of claim 6 wherein the inductor has the inductance selected from the range of 50 uH to 200 uH.
9. The retrofit LED lamp of claim 6 wherein the inductor prevents the formation of square waves between the ballast and the led retrofit lamp.
10. The retrofit LED lamp of claim 1 wherein a capacitor is placed in parallel with the string of LEDs and the output of the full wave bridge rectifier.