High efficiency, low energy storage driver circuit for solid state light sources
First Claim
1. A system to drive light emitting diodes (LEDs) comprising:
- a string of LEDs coupled across a voltage source configured to provide an input voltage, the string of LEDs comprising a plurality of separate groups of LEDs;
a plurality of switch circuits, each of the switch circuits comprising a switch coupled in parallel with an associated one of the groups of LEDs to control current flow through the associated group of LEDs in response to a control signal from a controller circuit;
a switch protection circuit associated with at least one of the switches; and
a steering circuit for each of the groups of LEDs wherein each steering circuit comprises a first steering diode in series with the associated group of LEDs and the associated switch circuit, and a second steering diode in series with the associated group of LEDs and the associated switch circuit.
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Accused Products
Abstract
A device, system and method to drive light emitting diodes (LEDs) are disclosed. An exemplary system may include a string of LEDs coupled across a voltage source configured to provide an input voltage. The string of LEDs may include a plurality of separate groups of LEDs and a plurality of switch circuits. Each of the switch circuits may include a switch coupled in parallel with an associated one of the groups of LEDs to control current flow through the associated group of LEDs in response to a control signal from a controller circuit. A switch protection circuit may be associated with at least one of the switches. A steering circuit may also be coupled in series and associated with each of the groups of LEDs.
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Citations
15 Claims
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1. A system to drive light emitting diodes (LEDs) comprising:
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a string of LEDs coupled across a voltage source configured to provide an input voltage, the string of LEDs comprising a plurality of separate groups of LEDs; a plurality of switch circuits, each of the switch circuits comprising a switch coupled in parallel with an associated one of the groups of LEDs to control current flow through the associated group of LEDs in response to a control signal from a controller circuit; a switch protection circuit associated with at least one of the switches; and a steering circuit for each of the groups of LEDs wherein each steering circuit comprises a first steering diode in series with the associated group of LEDs and the associated switch circuit, and a second steering diode in series with the associated group of LEDs and the associated switch circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of driving LEDs, comprising:
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coupling a string of LEDs across a voltage supply configured to provide an input voltage, the string of LEDs comprising a plurality of separate groups of LEDs; configuring a plurality of switches, each of the switches being coupled in parallel with an associated one of the groups of LEDs for controlling current flow through the associated group of LEDs in response to a control signal from a controller circuit; associating a switch protection circuit with at least one of the switches, the switch protection circuit configured to place the at least one of the switches into a conducting state in the event of failure of an LED in the associated group of LEDs, wherein the failure places the LED into an open state; and directing the flow of current to each group of LEDs with a steering circuit for each of said groups of LEDs coupled in series with each associated the groups of LEDs wherein each steering circuit has a first steering diode directing the flow of current in the opposite direction of a subsequent first steering diode of a subsequent steering circuit. - View Dependent Claims (13, 14)
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15. A system to drive light emitting diodes (LEDs) comprising:
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a string of LEDs coupled across a voltage source configured to provide an input voltage, the string of LEDs comprising a first group of LEDs and a second group of LEDs; a first switch circuit and a second switch circuit, each of the first and second switch circuits comprising a switch coupled in parallel with the associated one of the groups of LEDs to control current flow through the associated group of LEDs in response to a control signal from a controller circuit; a switch protection circuit associated with each the first switch circuit and the second switch circuit; a first steering circuit associated the first group of LEDs, comprising a first steering diode in series with the first group of LEDs and the associated switch circuit, and a second steering diode in series with the first group of LEDs and the associated switch circuit and opposite polarity with the first steering diode; and a second steering circuit associated the second group of LEDs, comprising a first steering diode in series with the second group of LEDs and the associated switch circuit, and a second steering diode in series with the second group of LEDs and the associated switch circuit and opposite polarity with the first steering diode wherein the first steering diode of second group of LEDs is in the opposite direction of the first steering diode of the first group of LEDs.
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Specification