US 8,823,270 B2 · Interchangeable LED bulbs

Abstract

Disclosed are circuits that allow LED bulbs to be replaced regardless of color or construction of the LED element. When used for an LED light string, replacing an LED bulb does not affect the operation of the entire string. When used for other illumination purpose, for example, room light, the bulbs are interchangeable because they have the same operating voltage and current. A standardized input impedance is selected for all of the LED bulbs regardless of construction and color. A resistor circuit is used to create the standardized input impedance while optimizing the operating parameters of the LED element. The resistor circuit includes a bypass element so that if a LED element burns open, a series wired LED string will not go dark. This eliminates the necessity for parallel connected LED bulbs and allows enjoyment of other advantages and economies of series wired LED strings.

Claims22

Dependent claims

An interchangeable LED bulb having a standardized input impedance that is based upon an input current (Iin) and an input voltage (Vin) applied to said interchangeable LED bulb when said interchangeable LED bulb that is disposed in an LED light string without substantially affecting performance and luminosity of said light string comprising:

an LED element having an operating voltage (VLED) that is applied across said LED element and an operating current (ILED) that flows through said LED element when said interchangeable LED bulb is placed in said LED light string;
a first resistor that is connected in series said LED element having a resistive value that is approximately equal to (Vin−VLED)/ILED
a second resistor that is connected in parallel with said first resistor and said LED element having a resistive value that is approximately equal to (Vin/(Iin−ILED) said first resistor and said second resistor being selected to have resistive values so that said LED element has a substantially predetermined luminosity and said interchangeable LED bulb has an input impedance that is substantially equal to said standardized input impedance so that said LED light string maintains a substantially uniform luminosity in said LED light string.

An interchangeable LED bulb having a standardized input impedance that is substantially equal to input impedances of other LED bulbs in an LED light string, said standardized input impedance being based upon an input current (Iin) and an input voltage (Vin) that is applied to said interchangeable LED bulb when said interchangeable LED bulb is disposed in an LED light string comprising:

an LED element that forms a part of said interchangeable LED bulb having an operating voltage VLED that is applied across said LED and an operating current ILED that flows through said LED element when said interchangeable LED bulb is placed in said LED light string;
a first resistor that forms a part of said interchangeable LED bulb, that is connected in series with said LED element having a resistive value that is approximately equal to VLED/(Iin−ILED);
a second resistor that forms a part of said interchangeable LED bulb, that is connected in parallel with said first resistor and said LED element having a resistive value that is approximately equal to (Vin−VLED)In, wherein said first resistor and said second resistor are selected to have resistive values so that said LED element creates a luminosity that is substantially the same as other LED elements in said LED light string, and said interchangeable LED bulb has an input impedance that is substantially equal to said standardized input impedance so that a substantially uniform luminosity is created from said interchangeable LED bulb and said other LED bulbs in said LED light string.

Dependencies are inferred from the claim text.

Interchangeable LED bulbs

Life of this patent

Interchangeable LED bulbs

Life of this patent

Abstract

Claims22