Circuit and method for driving LED lamp with a dimmer
First Claim
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1. A driver circuit for an LED (light-emitting diode) lamp, comprising:
- a transformer having a primary winding and a secondary winding;
a dimmer circuit coupled to a power source and the primary winding for varying an input voltage to the primary winding;
a power switch coupled to the primary winding for controlling a current flow in the primary winding;
an output rectifying circuit coupled to the secondary winding and the LED lamp for providing an output current to the LED lamp;
a controller coupled to the dimmer circuit to receive an average input voltage signal from the dimmer circuit, the controller being coupled to a control terminal of the power switch and configured to vary the output current according to the average input voltage signal.
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Abstract
A driver circuit for an LED (light-emitting diode) lamp includes a transformer having a primary winding and a secondary winding, a dimmer circuit coupled to a power source for varying an input voltage to the primary winding, and an output rectifying circuit coupled to the secondary winding for providing an output current to the LED lamp. The driver circuit also includes a controller coupled to the dimmer circuit to receive an average input voltage signal (DIM) from the dimmer circuit. The controller is configured to vary the output current according to the average input voltage.
55 Citations
13 Claims
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1. A driver circuit for an LED (light-emitting diode) lamp, comprising:
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a transformer having a primary winding and a secondary winding; a dimmer circuit coupled to a power source and the primary winding for varying an input voltage to the primary winding; a power switch coupled to the primary winding for controlling a current flow in the primary winding; an output rectifying circuit coupled to the secondary winding and the LED lamp for providing an output current to the LED lamp; a controller coupled to the dimmer circuit to receive an average input voltage signal from the dimmer circuit, the controller being coupled to a control terminal of the power switch and configured to vary the output current according to the average input voltage signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A driver circuit for an LED (light-emitting diode) lamp, comprising:
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a transformer having a primary winding and a secondary winding; a dimmer circuit coupled to a power source for varying an input voltage to the primary winding; an output rectifying circuit coupled to the secondary winding for providing an output current to the LED lamp; a controller coupled to the dimmer circuit to receive an average input voltage signal from the dimmer circuit, the controller being configured to vary the output current according to the average input voltage signal; wherein the controller includes a current control module, the current control module comprising; a voltage follower for receiving the DIM signal; a substractor coupled to the voltage follower; a first current mirror coupled to the substractor, a current selector configured to receive a current from the first current mirror; a second current mirror configured to receive a first reference voltage and to provide three reference currents, two of the reference currents being coupled to the current selector, wherein the current selector is configured to provide two output signals, a first output signal coupled to a peak current comparator, a second output signal coupled to a constant-current control circuit for adjusting a ratio of charging and discharging currents. - View Dependent Claims (9, 10, 11)
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12. A driver circuit for an LED (light-emitting diode) lamp, comprising:
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a transformer having a primary winding and a secondary winding; a dimmer circuit coupled to a power source for varying an input voltage to the primary winding; an output rectifying circuit coupled to the secondary winding for providing an output current to the LED lamp; a controller coupled to the dimmer circuit to receive an average input voltage signal from the dimmer circuit, the controller being configured to vary a duty cycle of a control signal to vary the output current according to the average input voltage signal. - View Dependent Claims (13)
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Specification