CIRCUITS AND METHODS FOR DRIVING LIGHT SOURCES
First Claim
1. A driving circuit for powering a light-emitting diode (LED) light source, said driving circuit comprising:
- a converter coupled to a switch operable in a first state and operable in a second state, and configured to receive an input voltage and provide a regulated voltage;
a transformer coupled to said converter and said switch, and configured to transform said regulated voltage to an output voltage to power said LED light source, wherein both a first current through said converter and a second current through said transformer further flow through said switch when said switch operates in said first state;
a first sensor coupled between said switch and a first reference node, and configured to provide a first sense signal indicating a combined current of said first current and said second current; and
a second sensor coupled between said first reference node and a second reference node, and configured to provide a second sense signal indicating only said second current.
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Accused Products
Abstract
A driving circuit includes a converter, a transformer, a first sensor and a second sensor. The converter is coupled to a switch that operates in a first state or in a second state. The converter receives an input voltage and provides a regulated voltage. The transformer transforms the regulated voltage to an output voltage to power said LED light source. Both a first current through the converter and a second current through the transformer further flow through the switch when the switch operates in the first state. The first sensor coupled between the switch and a first reference node provides a first sense signal indicating a combined current of the first current and the second current. The second sensor coupled between the first reference node and a second reference node provides a second sense signal indicating only the second current.
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Citations
34 Claims
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1. A driving circuit for powering a light-emitting diode (LED) light source, said driving circuit comprising:
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a converter coupled to a switch operable in a first state and operable in a second state, and configured to receive an input voltage and provide a regulated voltage; a transformer coupled to said converter and said switch, and configured to transform said regulated voltage to an output voltage to power said LED light source, wherein both a first current through said converter and a second current through said transformer further flow through said switch when said switch operates in said first state; a first sensor coupled between said switch and a first reference node, and configured to provide a first sense signal indicating a combined current of said first current and said second current; and a second sensor coupled between said first reference node and a second reference node, and configured to provide a second sense signal indicating only said second current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A controller for controlling power to a light-emitting diode (LED) light source, said controller comprising:
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an output pin configured to generate a driving signal to operate a switch, wherein a converter converts an input voltage to a regulated voltage based on operations of said switch, and wherein a transformer transforms said regulated voltage to an output voltage based on said operations to power said LED light source, wherein both a first current through said converter and a second current through said transformer further flow through said switch when said switch operates in a first state; a protection pin coupled to a protection circuit, wherein said protection circuit senses a combined current of said first current and said second current by detecting a total voltage across a first resistor and a second resistor, wherein said first resistor is coupled between said switch and a first reference node, and said second resistor is coupled between said first reference node and a second reference node; and a sense pin coupled to said first reference node, and configured to sense only said second current by detecting a voltage across said second resistor, wherein said controller controls said driving signal according to signals on said sense pin and said protection pin. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for controlling power to a light-emitting diode (LED) light source, said method comprising:
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converting an input voltage to a regulated voltage by a converter; transforming said regulated voltage to an output voltage by a transformer to power said LED light source; operating a switch according to a driving signal, wherein both a first current through said converter and a second current through said transformer further flow through said switch when said switch operates in a first state; receiving a first sense signal indicating a combined current of said first current and said second current by detecting a total voltage across a first sensor and a second sensor, wherein said first sensor is coupled between said switch and a first reference node, and wherein said second sensor is coupled between said first reference node and a second reference node; receiving a second sense signal indicating only said second current by detecting a voltage across only said second sensor; and controlling said driving signal to adjust a current flowing through said LED light source according to said first sense signal and said second sense signal. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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Specification