TRIAC DIMMABLE POWER SUPPLY UNIT FOR LED
First Claim
1. A power-factor-corrected power supply adapted to supply power to one or more light emitting diodes (LEDs), comprising:
- a triac dimmer electrically connected between an alternating current source and a bridge rectifier;
a damping circuit electrically connected between the alternating current source and the bridge rectifier;
a bleeder circuit configured to conduct current between a supply terminal of the bridge rectifier and ground only when a triac in the triac dimmer is not conducting current;
a fast startup circuit configured to conduct current between the supply terminal of the bridge rectifier and a voltage supply terminal of a power-factor-corrected controller when the triac dimmer is initially turned on until a supply voltage capacitor coupled to the voltage supply terminal of the power-factor-corrected controller has charged;
a dimming slope control circuit configured to reduce a first voltage sensed at a current sensing terminal of the power-factor-corrected controller, such that a reduced amount of current is supplied to the one or more LEDs at a given firing angle, wherein the first voltage is representative of a current flowing through a primary winding of a flyback transformer; and
a dummy load circuit provided in parallel with the one or more LEDs to draw a holding current for the triac only after the triac is turned on.
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Accused Products
Abstract
A power-factor-corrected power supply adapted to supply power to one or more light emitting diodes (LEDs), comprises: a triac dimmer electrically connected between an alternating current source and a bridge rectifier; a damping circuit electrically connected between the alternating current source and the bridge rectifier; a bleeder circuit configured to conduct current between a supply terminal of the bridge rectifier and ground only when a triac in the triac dimmer is not conducting current; a fast startup circuit configured to conduct current between the supply terminal of the bridge rectifier and a voltage supply terminal of a power-factor-corrected controller when the triac dimmer is initially turned on until a supply voltage capacitor coupled to the voltage supply terminal of the power-factor-corrected controller has charged; a dimming slope control circuit configured to reduce a first voltage sensed at a current sensing terminal of the power-factor-corrected controller, such that a reduced amount of current is supplied to the one or more LEDs at a given firing angle, wherein the first voltage is representative of a current flowing through a primary winding of a flyback transformer; and a dummy load circuit provided in parallel with the one or more LEDs to draw a holding current for the triac only after the triac is turned on.
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Citations
16 Claims
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1. A power-factor-corrected power supply adapted to supply power to one or more light emitting diodes (LEDs), comprising:
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a triac dimmer electrically connected between an alternating current source and a bridge rectifier; a damping circuit electrically connected between the alternating current source and the bridge rectifier; a bleeder circuit configured to conduct current between a supply terminal of the bridge rectifier and ground only when a triac in the triac dimmer is not conducting current; a fast startup circuit configured to conduct current between the supply terminal of the bridge rectifier and a voltage supply terminal of a power-factor-corrected controller when the triac dimmer is initially turned on until a supply voltage capacitor coupled to the voltage supply terminal of the power-factor-corrected controller has charged; a dimming slope control circuit configured to reduce a first voltage sensed at a current sensing terminal of the power-factor-corrected controller, such that a reduced amount of current is supplied to the one or more LEDs at a given firing angle, wherein the first voltage is representative of a current flowing through a primary winding of a flyback transformer; and a dummy load circuit provided in parallel with the one or more LEDs to draw a holding current for the triac only after the triac is turned on. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of supplying power to one or more light emitting diodes (LEDs) using a power-factor-corrected power supply that has:
- a triac dimmer electrically connected between an alternating current source and a bridge rectifier, a power-factor-corrected controller that controls the power factor of power supplied to the one or more LEDs, the method comprising;
damping, by a damping circuit electrically connected between the alternating current source and the bridge rectifier, current ringing at the output of the triac dimmer; controlling, by a bleeder circuit provided between a supply terminal of the bridge rectifier and ground, so that current flows between the supply terminal of the bridge rectifier and ground only when a triac in the triac dimmer is not conducting current; controlling, by a fast startup circuit provided between the supply terminal of the bridge rectifier and a voltage supply terminal of the power-factor-corrected controller, so that current is conducted between the supply terminal of the bridge rectifier and the voltage supply terminal of the power-factor-corrected controller when the triac dimmer is initially turned on until a supply voltage capacitor coupled to the voltage supply terminal of the power-factor-corrected controller has charged; reducing, by a dimming slope control circuit, a first voltage sensed at a current sensing terminal of the power-factor-corrected controller, such that a reduced amount of current is supplied to the one or more LEDs at a given firing angle of the triac, wherein the first voltage is representative of a current flowing through a primary winding of a flyback transformer; and drawing, by a dummy load circuit provided in parallel with the one or more LEDs, a holding current for the triac only after the triac is turned on. - View Dependent Claims (12, 13, 14, 15, 16)
- a triac dimmer electrically connected between an alternating current source and a bridge rectifier, a power-factor-corrected controller that controls the power factor of power supplied to the one or more LEDs, the method comprising;
Specification