CMOS adjustable over voltage ESD and surge protection for LED application
View Patent ↗Various embodiments relate to a light emitting diode protection circuit, including: a plurality of diodes connected in series; an input connected to a first diode of the plurality of diodes; an output; a first resistor connected between the plurality of diodes and the output; a transistor with a gate connected to a junction between the first resistor and the plurality of diodes and a source connected to the output; a second resistor connected between the input and drain of the transistor; and a silicon controlled rectifier (SCR) with an anode connected to the input, a base connected to the drain of the transistor, and a cathode connected to the output.
1. A light emitting diode protection circuit, comprising:
a plurality of diodes connected in series;
a first input connected to a first diode of the plurality of diodes;
a second input connected to a junction between two of the plurality of diodes, wherein shorting the first input to the second input reduces a breakdown voltage of the plurality of diodes;
an output;
a first resistor connected between the plurality of diodes and the output;
a transistor with a gate connected to a junction between the first resistor and the plurality of diodes and a source connected to the output;
a second resistor connected between the first input and a drain of the transistor; and
a silicon controlled rectifier (SCR) with an anode connected to the first input, a base connected to the drain of the transistor, and a cathode connected to the output.
2. The light emitting diode protection circuit of claim 1 , wherein a plurality of the light emitting diode protection circuits are configured to protect a plurality of LEDs connected in series.
3. The light emitting diode protection circuit of claim 1 , wherein the transistor is a NMOS transistor.
4. The light emitting diode protection circuit of claim 1 , wherein the plurality of diodes are transistor diodes.
5. The light emitting diode protection circuit of claim 1 , wherein the light emitting diode protection circuit is a CMOS chip.
6. A light emitting diode protection circuit, comprising:
a plurality of diodes connected in series;
a first input connected to a first diode of the plurality of diodes;
a second input connected to a junction between two of the plurality of diodes, wherein shorting the first input to the second input reduces a breakdown voltage of the plurality of diodes;
an output;
a first resistor connected between the plurality of diodes and the output;
a transistor with a gate connected to a junction between the first resistor and the plurality of diodes and a source connected to the output; and
a silicon controlled rectifier (SCR) with an anode connected to the first input, a base connected to the drain of the transistor, and a cathode connected to the output.
7. The light emitting diode protection circuit of claim 6 , wherein a plurality of light emitting diode protection circuits are configured to protect a plurality of LEDs connected in series.
8. The light emitting diode protection circuit of claim 6 , wherein the transistor is a NMOS transistor.
9. The light emitting diode protection circuit of claim 6 , wherein the plurality of diodes are transistor diodes.
10. The light emitting diode protection circuit of claim 6 , wherein the light emitting diode protection circuit is a CMOS chip.
11. A light emitting diode (LED) system, comprising:
a plurality of LEDs connected in series;
a plurality of LED protection circuits each connected in parallel to one of the plurality of LEDs connected in series, each of the plurality of LED protection circuits further comprising:
a plurality of diodes connected in series;
a first input connected to a first diode of the plurality of diodes and a first of the plurality of LEDs;
a second input connected to a junction between two of the plurality of diodes and connected to the first input, wherein shorting the first input to the second input reduces a breakdown voltage of the plurality of diodes;
an output connected to a last of the plurality of the LEDs;
a first resistor connected between the plurality of diodes and the output;
a transistor with a gate connected to a junction between the first resistor and the plurality of diodes and a source connected to the output; and
a silicon controlled rectifier (SCR) with an anode connected to the first input, a base connected to the drain of the transistor, and a cathode connected to the output.
12. The light emitting diode protection circuit of claim 11 , further comprising:
a second resistor connected between the gate of the SCR and the drain of the transistor.
13. The light emitting diode protection circuit of claim 11 , wherein the transistor is a NMOS transistor.
14. The light emitting diode protection circuit of claim 11 , wherein the plurality of diodes are transistor diodes.