LED Drivers and Control Methods
First Claim
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1. An LED driver comprising:
- an input for receiving a rectified AC voltage;
an output for providing an output current;
a power converter coupled between the input and the output to receive the rectified AC voltage and generate the output current, the power converter including a switch and an inductive element, the switch coupled to the inductive element; and
a controller for controlling the power converter at a substantially constant frequency to provide the output current and active power factor correction, the controller configured to control an on time of the switch as a function of a current through the inductive element and the rectified AC voltage.
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Abstract
A method of operating an LED driver including a power converter to generate an output current for powering an LED and to provide active power factor correction is disclosed. The power converter is coupled between an input to receive a rectified AC voltage and an output for providing the output current to the LED. The method includes operating the power converter at a substantially fixed frequency in an open loop mode based on a current through the inductive element and the rectified AC voltage. LED drivers operable in accordance with the disclosed method are disclosed.
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Citations
20 Claims
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1. An LED driver comprising:
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an input for receiving a rectified AC voltage; an output for providing an output current; a power converter coupled between the input and the output to receive the rectified AC voltage and generate the output current, the power converter including a switch and an inductive element, the switch coupled to the inductive element; and a controller for controlling the power converter at a substantially constant frequency to provide the output current and active power factor correction, the controller configured to control an on time of the switch as a function of a current through the inductive element and the rectified AC voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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- 12. A method of operating an LED driver including a power converter to generate an output current for powering an LED and to provide active power factor correction, the power converter coupled between an input to receive a rectified AC voltage and an output for providing the output current to the LED, the method comprising operating the power converter at a substantially fixed frequency in an open loop mode based on a current through the inductive element and the rectified AC voltage.
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16. An LED driver comprising:
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an input for receiving a rectified AC voltage as an input voltage; a power converter connected the input to receive the input voltage and output an output current, the power converter including an inductive element coupled to the input and a switch coupled to the inductive element; and a controller for controlling operation of the power converter to generate the output current and provide active power factor correction, the controller including; a scaling circuit connected to the input to generate a scaled input voltage; a current reference generator connected to the scaling circuit to generate a current reference as a function of the scaled input voltage; a switch controller to control the switch based on the current reference and a signal representative of the current through the inductive element. - View Dependent Claims (17, 18, 19, 20)
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Specification