Mixed load current compensation for LED lighting
First Claim
1. A method comprising:
- detecting a leading edge of a dimmer phase-cut voltage;
after detecting the leading edge, controlling a lamp current of an electronic lamp to prevent a current through a triac of the dimmer from undershooting a holding current value, wherein the holding current value represents a value that if undershot by the current through the triac of the dimmer would stop the triac from conducting, wherein controlling the lamp current of the electronic lamp to prevent the current through the triac of the dimmer from undershooting the holding current value includes;
responding to an increase in the dimmer phase-cut voltage after detection of the leading edge that would otherwise cause the current through the triac to undershoot the holding current value by causing a generation of a compensating current that increases the lamp current and prevents the current through the triac from undershooting the holding current value.
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Accused Products
Abstract
In at least one embodiment, a system and method provide current compensation in a lighting system by controlling a lamp current to prevent a current through a triac-based dimmer from undershooting a holding current value. In at least one embodiment, at least one of the lamps includes a controller that controls circuitry in the lamp to draw more lamp current for a period of time than needed to illuminate a brightness of the lamp at a level corresponding to particular phase-cut angle of the supply voltage. By drawing more current than needed, the controller increases the dimmer current during the period of time to prevent the dimmer current from falling below the holding current value. In at least one embodiment, the period of time corresponds to a compensating pulse of the lamp current at a time when the dimmer current would otherwise fall below the holding current value.
116 Citations
35 Claims
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1. A method comprising:
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detecting a leading edge of a dimmer phase-cut voltage; after detecting the leading edge, controlling a lamp current of an electronic lamp to prevent a current through a triac of the dimmer from undershooting a holding current value, wherein the holding current value represents a value that if undershot by the current through the triac of the dimmer would stop the triac from conducting, wherein controlling the lamp current of the electronic lamp to prevent the current through the triac of the dimmer from undershooting the holding current value includes; responding to an increase in the dimmer phase-cut voltage after detection of the leading edge that would otherwise cause the current through the triac to undershoot the holding current value by causing a generation of a compensating current that increases the lamp current and prevents the current through the triac from undershooting the holding current value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 32, 33)
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15. An apparatus comprising:
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a controller, wherein the controller is configured to; detect a leading edge of a dimmer phase-cut voltage; after detecting the leading edge, control a lamp current of an electronic lamp to prevent a current through a triac of the dimmer from undershooting a holding current value, wherein the holding current value represents a value that if undershot by the current through the triac of the dimmer would stop the triac from conducting, wherein to the lamp current of the electronic lamp to prevent the current through the triac of the dimmer from undershooting the holding current value the controller is configured to; respond to an increase in the dimmer phase-cut voltage after detection of the leading edge that would otherwise cause the current through the triac to undershoot the holding current value by causing a generation of a compensating current that increases the lamp current to prevent the current through the triac from undershooting the holding current value. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 34, 35)
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31. An apparatus comprising:
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a lamp, wherein the lamp comprises; a switching power converter; one or more light emitting diodes coupled to the switching power converter; and a controller, coupled to the switching power converter, wherein the controller is configured to; detect a leading edge of a dimmer phase-cut voltage; after detecting the leading edge, control a lamp current of the lamp to prevent a current through a triac of the dimmer from undershooting a holding current value, wherein the holding current value represents a value that if undershot by the current through the triac of the dimmer would stop the triac from conducting, wherein to the lamp current of the electronic lamp to prevent the current through the triac of the dimmer from undershooting the holding current value the controller is configured to; respond to an increase in the dimmer phase-cut voltage after detection of the leading edge that would otherwise cause the current through the triac to undershoot the holding current value by causing a generation of a compensating current that increases the lamp current to prevent the current through the triac from undershooting the holding current value.
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Specification