Transistor ladder network for driving a light emitting diode series string
First Claim
1. A circuit for controlling operation of a string of light emitting diodes (LEDS), comprising:
- a number of sections connected in series, the sections being configured for connection to a power source, wherein each section comprises;
at least one LED;
a variable resistive element coupled to the LED section;
a transistor coupled to the variable resistive element; and
a switch coupled to the LED section, the variable resistive element, and the transistor,wherein the switch with the variable resistive element and the transistor activates the LED section and controls current through the LED,wherein, when receiving power from the power source, the sections activate the LED sections in sequence throughout the series of the sections,further comprising a first resistive element coupled between the switch and the variable resistive element and a second resistive element coupled between the switch and the transistor.
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Accused Products
Abstract
Ladder network circuits for controlling operation of a string of light emitting diodes (LEDS). The circuits include a number of sections connected in series. Each section includes one or more LED junctions, a variable resistive element coupled to the LED section, and a switch coupled to the variable resistive element and the LED section for controlling activation of the LED. The sections can include a transistor coupled between the switch and variable resistive element. The series of sections are connected to an AC power source, rectifier, and dimmer circuit. When receiving power from the power source, the sections activate the LEDs in sequence throughout the series of the sections. The dimmer circuit controls activation of a selection of one or more of the sections in order to activate in sequence the LEDs in only the selected sections, providing for both dimming and color control of the LEDs.
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Citations
18 Claims
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1. A circuit for controlling operation of a string of light emitting diodes (LEDS), comprising:
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a number of sections connected in series, the sections being configured for connection to a power source, wherein each section comprises; at least one LED; a variable resistive element coupled to the LED section; a transistor coupled to the variable resistive element; and a switch coupled to the LED section, the variable resistive element, and the transistor, wherein the switch with the variable resistive element and the transistor activates the LED section and controls current through the LED, wherein, when receiving power from the power source, the sections activate the LED sections in sequence throughout the series of the sections, further comprising a first resistive element coupled between the switch and the variable resistive element and a second resistive element coupled between the switch and the transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A circuit for controlling operation of a string of light emitting diodes (LEDS), comprising:
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a number of sections connected in series, the sections being configured for connection to a power source, wherein each section comprises; at least one LED; a variable resistive element coupled to the LED section; a transistor coupled to the variable resistive element; and a switch coupled to the LED section, the variable resistive element, and the transistor, wherein the switch with the variable resistive element and the transistor activates the LED section and controls current through the LED, wherein, when receiving power from the power source, the sections activate the LED sections in sequence throughout the series of the sections, further comprising a capacitor coupled between the switch and the transistor. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification