Method and circuit for driving an LED load with phase-cut dimmers
First Claim
1. A dimmable driver circuit for a light-emitting diode (LED) load, the dimmable driver circuit comprising:
- an alternating current (AC)-direct current (DC) rectifier configured to convert an AC input voltage into a DC voltage;
a damper and filter circuit configured to provide a latching current to a phase-cut dimmer and to suppress an inrush current caused by phase-cut dimming, and to filter electromagnetic interference (EMI) noise from the DC voltage; and
a switching converter circuit connected to the damper and filter circuit and configured to operate in a boundary conduction mode (BCM) with a constant on-time and a constant peak current to generate DC power for the LED load,wherein the switching converter draws a current from the AC input voltage, the current including a quasi-sinusoidal current waveform in a low voltage region of the AC input voltage and a second current waveform that is flatter than the quasi-sinusoidal current waveform in a high voltage region of the AC input voltage, wherein the quasi-sinusoidal current waveform extends higher in the low voltage region of the AC input voltage compared to a typical sinusoidal current waveform to support deep dimming, and wherein the switching converter comprises a buck converter.
14 Assignments
0 Petitions
Accused Products
Abstract
Embodiments of a dimmable driver circuit for a light-emitting diode (LED) load and a method for driving an LED load are described. In one embodiment, a dimmable driver circuit for an LED load includes an alternating current (AC)-direct current (DC) rectifier configured to convert an AC input voltage into a DC voltage, a damper and filter circuit configured to provide a latching current to a phase-cut dimmer and to suppress an inrush current caused by phase-cut dimming, and to filter electromagnetic interference (EMI) noise from the DC voltage, and a switching converter circuit connected to the damper and filter circuit and configured to operate in a boundary conduction mode (BCM) with a constant on-time to generate DC power for the LED load in response to the DC voltage. Other embodiments are also described.
-
Citations
18 Claims
-
1. A dimmable driver circuit for a light-emitting diode (LED) load, the dimmable driver circuit comprising:
-
an alternating current (AC)-direct current (DC) rectifier configured to convert an AC input voltage into a DC voltage; a damper and filter circuit configured to provide a latching current to a phase-cut dimmer and to suppress an inrush current caused by phase-cut dimming, and to filter electromagnetic interference (EMI) noise from the DC voltage; and a switching converter circuit connected to the damper and filter circuit and configured to operate in a boundary conduction mode (BCM) with a constant on-time and a constant peak current to generate DC power for the LED load, wherein the switching converter draws a current from the AC input voltage, the current including a quasi-sinusoidal current waveform in a low voltage region of the AC input voltage and a second current waveform that is flatter than the quasi-sinusoidal current waveform in a high voltage region of the AC input voltage, wherein the quasi-sinusoidal current waveform extends higher in the low voltage region of the AC input voltage compared to a typical sinusoidal current waveform to support deep dimming, and wherein the switching converter comprises a buck converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. A method for driving a light-emitting diode (LED) load, the method comprising:
-
converting an alternating current (AC) input voltage into a direct current (DC) voltage; providing a latching current to turn on a phase-cut dimmer for phase-cut dimming; suppressing an inrush current caused by the phase-cut dimming; filtering electromagnetic interference (EMI) noise from the DC voltage using an electromagnetic interference (EMI) filter; and operating a switching converter in a boundary conduction mode (BCM) with a constant on-time and a constant peak current to generate DC power for the LED load, wherein operating the switching converter in the boundary conduction mode (BCM) comprises drawing a current from the AC input voltage by the switching converter, the current including a quasi-sinusoidal current waveform in a low voltage region of the AC input voltage and a second current waveform that is flatter than the quasi-sinusoidal current waveform in a high voltage region of the AC input voltage, wherein the quasi-sinusoidal current waveform extends higher in the low voltage region of the AC input voltage compared to a typical sinusoidal current waveform to support deep dimming, and wherein the switching converter comprises a buck converter.
-
-
15. A dimmable driver circuit for a light-emitting diode (LED) load, the dimmable driver circuit comprising:
-
an alternating current (AC)-direct current (DC) rectifier configured to convert an AC input voltage into a DC voltage; a damper circuit connected to the AC-DC rectifier and configured to provide a latching current to a phase-cut dimmer and to suppress an inrush current caused by phase-cut dimming; an electromagnetic interference (EMI) filter configured to filter electromagnetic interference noise from the DC voltage; a switching converter configured to convert the DC voltage from one DC voltage level to another DC voltage level; and a switching converter controller connected to the EMI filter and to the switching converter and configured to cause the switching converter to operate in a boundary conduction mode (BCM) with the constant on-time and a constant peak current, wherein the switching converter draws a current from the AC input voltage, the current including a quasi-sinusoidal current waveform in a low voltage region of the AC input voltage and a second current waveform that is flatter than the quasi-sinusoidal current waveform in a high voltage region of the AC input voltage, wherein the quasi-sinusoidal current waveform extends higher in the low voltage region of the AC input voltage compared to a typical sinusoidal current waveform to support deep dimming, and wherein the switching converter comprises a buck converter. - View Dependent Claims (16, 17, 18)
-
Specification