3-way LED bulb
Circuits to make a 3-way LED light bulb correctly interface to a standard 3-way light socket, producing three levels of light corresponding to the three settings of the socket. One of the circuits prevents color shift due to varying LED current.
1. A circuit for driving an LED light bulb at varying levels of brightness depending on the energization of a 3-way socket comprising:
a pair of inputs, each input having a rectifier bridge associated therewith and producing parallel outputs;
at least one LED;
a power system for the at least one LED, which runs from the parallel outputs of the rectifier bridges;
an energization detector circuit for each pair of inputs; and
a selection circuit that selects a current feedback for the power system, and
wherein the feedback is dependant on an output of the energization detector circuits.
2. A circuit for driving an LED light bulb at varying levels of brightness depending on the energization of a 3-way socket as set forth in claim 1 , wherein said energization detector circuit consists of a half wave rectifier, a resistor divider and a capacitive filter.
3. A circuit for driving an LED light bulb at varying levels of brightness depending on the energization of a 3-way socket as set forth in claim 1 , wherein the selection circuit consists of a pair of gain-setting circuits for each pair of inputs.
4. A circuit for driving an LED light bulb at varying levels of brightness depending on the energization of a 3-way socket as set forth in claim 3 , wherein each of the pair of gain-setting circuits consist of a transistor in series with a current-sense resistor.
5. A circuit for driving an LED light bulb at varying levels of brightness depending on the energization of a 3-way socket comprising:
a pair of inputs, each input having a rectifier bridge associated therewith and producing parallel outputs;
at least two strings of LEDs, each consisting of at least one LED;
a power system for the at least two strings of LEDs, which runs from the parallel outputs of the rectifier bridges;
an energization detector circuit for each pair of inputs;
a selection circuit that selectively shunts one or more of the at least two strings of LEDs dependant on an output of the energization detector circuits; and
wherein the selection circuit consists of a pair of shunt circuits for each input.
6. A circuit for driving an LED light bulb at varying levels of brightness depending on the energization of a 3-way socket as set forth in claim 5 , wherein the shunt circuits consist of a transistor.
7. A circuit for driving an LED light bulb at varying levels of brightness depending on the energization of a 3-way socket as set forth in claim 5 , wherein the shunt circuits consist of a transistor along with a gate protection circuitry.
8. A circuit for driving an LED light bulb at varying levels of brightness depending on the energization of a 3-way socket comprising:
a pair of inputs, each input having a rectifier bridge associated therewith and producing parallel outputs;
at least two strings of LEDs, each consisting of at least one LED;
a power system for the at least two strings of LEDs, which runs from the parallel outputs of the rectifier bridges;
an energization detector circuit for each pair of inputs;
a selection circuit that selectively shunts one or more of the at least two strings of LEDs dependant on an output of the energization detector circuits; and
wherein each of the energization detector circuits consist of a half wave rectifier, a resistor divider and a capacitive filter.