Circuits and methods for controlling power of light sources
First Claim
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1. A driving circuit for driving a light emitting diode (LED) light source, comprising:
- a power converter coupled to said LED light source and operable for receiving an input voltage from a power source and for providing an output voltage to said LED light source, said power converter comprising a switch coupled in series with said LED light source;
a controller coupled to said power converter and operable for controlling a power of said LED light source by controlling said switch;
a voltage-controlled current source coupled to said controller and operable for providing a first current, wherein said controller controls said switch based on said first current; and
a first resistor coupled between said controller and ground,wherein said controller is operable for providing a second current, wherein a third current flowing through said first resistor is determined by a combination of said first current and said second current, wherein said controller is operable for adjusting said second current based on said first current to maintain said third current substantially constant, and wherein said controller is operable for generating a control signal based on said second current to control said switch.
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Abstract
A driving circuit for driving a light source includes a power converter, a controller and a voltage-controlled current source. The power converter is coupled to the light source, and receives an input voltage from a power source and provides an output voltage to the light source. The power converter includes a switch coupled in series with the light source. The controller is coupled to the power converter and controls a power of the light source by controlling the switch. The voltage-controlled current source is coupled to the controller and provides a first current. The controller controls the switch based on the first current.
21 Citations
17 Claims
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1. A driving circuit for driving a light emitting diode (LED) light source, comprising:
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a power converter coupled to said LED light source and operable for receiving an input voltage from a power source and for providing an output voltage to said LED light source, said power converter comprising a switch coupled in series with said LED light source; a controller coupled to said power converter and operable for controlling a power of said LED light source by controlling said switch; a voltage-controlled current source coupled to said controller and operable for providing a first current, wherein said controller controls said switch based on said first current; and a first resistor coupled between said controller and ground, wherein said controller is operable for providing a second current, wherein a third current flowing through said first resistor is determined by a combination of said first current and said second current, wherein said controller is operable for adjusting said second current based on said first current to maintain said third current substantially constant, and wherein said controller is operable for generating a control signal based on said second current to control said switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A driving circuit for controlling power of a light emitting diode (LED) light source, comprising:
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a voltage-controlled current source operable for providing a first current; a controller coupled to said voltage-controlled current source and operable for providing a second current; a pulse signal generator operable for generating a pulse signal based on said second current to control a switch coupled in series with said LED light source, wherein said controller is operable for adjusting said second current based on said first current; and a first resistor coupled between said controller and ground, wherein a third current flowing through said first resistor is determined by a combination of said first current and said second current, and wherein said controller adjusts said second current based on said first current to maintain said third current substantially constant. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification