Back to results
US 9,807,841 B2Granted
Circuit for expanding the dimming range of an LED lamp
AssigneeHubbell Incorporated
InventorStephen M. Liscinsky
Life of this patent
Estimating the term…
Abstract
A circuit and method for controlling one or more light emitting diodes (LEDs) includes one or more LEDs connected to the emitter a transistor and controlling the brightness of the LEDs over a large range based on a voltage range at a base of the transistor controlled by an automatic adjusting mechanism.
Claims17
A circuit for controlling a brightness of a light emitting diode (LED), the circuit comprising:
- a transistor having a base, an emitter, and a collector, wherein said emitter is configured to emit a forward current;
- a voltage source configured to generate a voltage at said base of said transistor, wherein said voltage at said base of said transistor is configured to control said forward current emitted by said emitter;
- and
- said LED disposed between said emitter of said transistor and an electrical ground and configured to generate light and receive said forward current from said emitter, wherein said brightness of said LED depends on said voltage generated at said base of said transistor and said forward current received from said emitter;
- and
- an automatic adjusting circuit including a sensor configured to measure an amount of ambient light,
- wherein said brightness of said light generated by said LED varies within a continuous range from zero millicandelas when said amount of ambient light is greater than a predetermined first threshold to greater than fifty thousand millicandelas when said amount of ambient light is less than a predetermined second threshold,
- wherein said automatic adjusting circuit is configured to
- control said voltage at said base of said transistor to be at least 1.80 volts when said amount of ambient light is greater than said predetermined first threshold, and
- control said voltage at said base of said transistor to be up to 2.3 volts when said amount of ambient light is less than said predetermined second threshold.
7 more elements
An electrical wiring device comprising:
- a light emitting diode (LED);
- a housing including a plurality of line terminals and a lens from which light from said LED emanates;
- and
- a circuit for controlling a brightness of said LED, said circuit including
- a transistor having a base, an emitter, and a collector, wherein said emitter is configured to emit a forward current, and
- an automatic adjusting circuit configured to control a voltage at said base of said transistor, wherein said voltage at said base of said transistor is configured to control said forward current emitted by said emitter, said automatic adjusting circuit including a sensor configured to measure an amount of ambient light that is external to said housing,
- wherein said LED is disposed between said emitter of said transistor and an electrical ground and configured to receive said forward current from said emitter of said transistor, and wherein said brightness of said LED depends on said voltage at said base of said transistor and said forward current received from said emitter,
- wherein said brightness of said light generated by said LED varies within a continuous range from zero millicandelas when said amount of ambient light is greater than a predetermined first threshold to greater than fifty thousand millicandelas when said amount of ambient light is less than a predetermined second threshold,
- wherein said automatic adjusting circuit is configured to
- control said voltage at said base of said transistor to be at least 1.80 volts when said amount of ambient light is greater than said predetermined first threshold, and
- control said voltage at said base of said transistor to be up to 2.3 volts when said amount of ambient light is less than said predetermined second threshold.
8 more elements
A method of controlling a brightness of one or more light emitting diodes (LEDs), the method comprising:
- disposing one or more LEDs in an emitter circuit of a transistor between said emitter circuit and an electrical ground;
- receiving, with said one or more LEDs, a forward current, wherein said brightness of said one or more LEDs depends on a voltage at a base of said transistor and current level of said forward current emitted by said emitter circuit of said transistor;
- measuring an amount of ambient light;
- controlling said voltage at said base of said transistor to be at least 1.80 volts when said amount of ambient light is greater than a predetermined first threshold;
- and
- controlling said voltage at said base of said transistor to be up to 3.12 volts when said amount of ambient light is less than a predetermined second threshold.
3 more elements
Dependencies are inferred from the claim text.