Lighting system with power factor correction control data determined from a phase modulated signal
First Claim
1. A light emitting diode (LED) lighting system comprising:
- a controller comprising;
an input to receive a phase delay signal indicating a phase delay of a phase modulated dimmer signal; and
a signal processor, coupled to the input, to receive the phase delay signal and determine a control operating parameter from the phase delay signal and to generate a switch control signal using the determined operating parameter to vary an input current to a switching power converter with a phase modulated voltage and to maintain a regulated link voltage at an approximately constant value until a duty cycle of the control signal decreases to a predetermined threshold value and to decrease the regulated link voltage of the switching power converter when the duty cycle of the control signal decreases to the predetermined duty cycle threshold value.
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Accused Products
Abstract
A light emitting diode (LED) lighting system includes a power factor correction (PFC) controller that determines at least one power factor correction control parameter from phase delays of a phase modulated signal. In at least one embodiment, a peak voltage of the phase modulated signal is a PFC control parameter used by the PFC controller to control power factor correction and generation of a link voltage by a PFC LED driver circuit. The phase delays are related to a peak voltage of the phase modulated signal. Thus, in at least one embodiment, detecting the phase delay in one or more cycles of the phase modulated signal allows the PFC controller to determine the peak voltage of the phase modulated signal.
109 Citations
19 Claims
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1. A light emitting diode (LED) lighting system comprising:
a controller comprising; an input to receive a phase delay signal indicating a phase delay of a phase modulated dimmer signal; and a signal processor, coupled to the input, to receive the phase delay signal and determine a control operating parameter from the phase delay signal and to generate a switch control signal using the determined operating parameter to vary an input current to a switching power converter with a phase modulated voltage and to maintain a regulated link voltage at an approximately constant value until a duty cycle of the control signal decreases to a predetermined threshold value and to decrease the regulated link voltage of the switching power converter when the duty cycle of the control signal decreases to the predetermined duty cycle threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of controlling a light emitting diode (LED) lighting system, the method comprising:
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receiving a phase delay signal indicating a phase delay of a phase modulated dimmer signal; determining a control operating parameter from the phase delay signal using a signal processor; and generating a duty cycle modulated switch control signal using the determined operating parameter to vary an input current to a switching power converter with a phase modulated voltage and to maintain a regulated link voltage at an approximately constant value until a duty cycle of the switch control signal decreases to a predetermined threshold value and to decrease the regulated link voltage of the switching power converter when the duty cycle of the switch control signal decreases to the predetermined duty cycle threshold value. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A light emitting diode (LED) lighting system comprising:
a controller comprising; an input to receive a phase delay signal indicating a phase delay of a phase modulated dimmer signal; and a signal processor, coupled to the input, to receive the phase delay signal and determine a control operating parameter from the phase delay signal and to generate a switch control signal using the determined operating parameter to control an input current in response to one or more values of the phase delay signal; and wherein the controller is further configured to decrease a duty cycle of the switch control signal as the dimming level decreases until the dimming level reaches a dimming level threshold and to keep the duty cycle of the switch control signal approximately constant for dimming levels below the dimming level threshold. - View Dependent Claims (18)
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19. A light emitting diode (LED) lighting system comprising:
a controller comprising; an input to receive a phase delay signal indicating a phase delay of a phase modulated dimmer signal; and a signal processor, coupled to the input, to receive the phase delay signal and determine a control operating parameter from the phase delay signal and to generate a switch control signal using the determined operating parameter to control an input current in response to one or more values of the phase delay signal; wherein the controller is further configured to increase an effective resistance of the switching power converter as the dimming level indicated by the dimming signal decreases.
Specification