Light emitting diode light structures
A Light Emitting Diode (LED) light includes a bridge rectifier configured to be powered by an alternating current power source and to produce a rectified output. Control circuitry couples to the bridge rectifier and is configured to produce a shunt signal when the rectified output is less than a threshold voltage. A series connected Light Emitting Diode (LED) string includes a first group of LEDs and a second group of LEDs. A switch couples to a first side of the second group of LEDs and is controlled by the shunt signal to deactivate the second group of LEDs. The control circuitry may include a ratio metric series resistor string configured to sense a proportion of the rectified output and an inverter configured to generate the shunt signal based on the proportion of the rectified output.
1. An integrated circuit configured to interface with a series connected Light Emitting Diode (LED) string having a primary group of LEDs and a secondary group of LEDs, a first LED drive input connected to a first side of the primary group of LEDs, a secondary LED drive input connected to a second side of the primary group of LEDs and a first side of the secondary group of LEDs, and a third LED drive input connected to a secondary side of the secondary group of LEDs, the integrated circuit comprising:
a bridge rectifier configured to convert an alternating current power source to a rectified output;
a first drive output configured to couple to the first LED drive input;
a second drive output to the second LED drive input;
a third drive output configured to couple to the third LED drive input;
control circuitry configured to produce a shunt signal based upon a voltage of the rectified output; and
a switch configured to selectively shunt the second drive output and the third drive output in response to the shunt signal.
2. The integrated circuit of claim 1 , wherein the first drive output also couples to the rectified output.
3. The integrated circuit of claim 1 , further comprising dimming circuitry.
4. The integrated circuit of claim 1 , wherein the control circuitry comprises:
a voltage divider; and
a second switch having an output coupled to the switch.
5. The integrated circuit of claim 4 , wherein the second switch comprises a transistor.
6. The integrated circuit of claim 1 , further comprising a communication module.
7. The integrated circuit of claim 6 , wherein the communication module supports Radio Frequency (RF) communications.
8. The integrated circuit of claim 6 , wherein the communication module supports communications with at least one computing device.
9. The integrated circuit of claim 8 , wherein the control circuitry is configured to control operation of the series connected LED string based upon the communications with the at least one computing device.
10. An integrated circuit configured to interface with a bridge rectifier that converts an alternating current power source to a rectified output and a series connected Light Emitting Diode (LED) string having a primary group of LEDs and a secondary group of LEDs, a first LED drive input connected to a first side of the primary group of LEDs, a secondary LED drive input connected to a second side of the primary group of LEDs and a first side of the secondary group of LEDs, and a third LED drive input connected to a secondary side of the secondary group of LEDs, the integrated circuit comprising:
a bridge rectifier input configured to couple to the rectified output;
a first drive output configured to couple to the first LED drive input;
a second drive output configured to couple to the second LED drive input;
a third drive output configured to couple to the third LED drive input;
control circuitry configured to produce a shunt signal based upon a voltage of the rectified output; and
a switch configured to selectively shunt the second drive output and the third drive output in response to the shunt signal.
11. The integrated circuit of claim 10 , wherein the first drive output also couples to the rectified output.
12. The integrated circuit of claim 10 , further comprising dimming circuitry.
13. The integrated circuit of claim 10 , wherein the control circuitry comprises:
a voltage divider; and
a second switch having an output coupled to the switch.
14. The integrated circuit of claim 13 , wherein the second switch comprises a transistor.
15. The integrated circuit of claim 10 , further comprising a communication module.
16. The integrated circuit of claim 15 , wherein the communication module supports Radio Frequency (RF) communications.
17. The integrated circuit of claim 15 , wherein the communication module supports communications with at least one computing device.
18. The integrated circuit of claim 17 , wherein the control circuitry is configured to control operation of the series connected LED string based upon the communications with the at least one computing device.