Method and apparatus for LED dimming
First Claim
1. An LED driver comprising:
- an input configured to accept an AC signal;
a rectifier in electrical communication with the input, the rectifier configured to rectify the AC signal into a pulse train comprising one or more pulses;
a comparator in electrical communication with the rectifier, the comparator configured to utilize a voltage threshold whereby the comparator outputs a first signal while a voltage of the one or more pulses is above the voltage threshold and outputs a second signal while the voltage of the one or more pulses is below the voltage threshold;
a controller in electrical communication with the comparator, the controller configured to determine a pulse width of the one or more pulses and a period of the AC signal from the first signal and the second signal whereby the controller is configured to determine a desired level of light output based on a ratio of the pulse width to the period and generate an output signal configured to provide the desired level of light output through LED lighting; and
an output configured to provide the output signal to the LED lighting.
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Accused Products
Abstract
A dimmable LED driver provides accurate full range dimming for LED lighting. The driver utilizes the timing of an AC signal rather than its power output or other characteristics to accurately determine the level of light a user desires. In this manner, the driver provides accurate full range dimming without the need for calibration to specific AC power levels. The driver may detect the period of an AC signal allowing the driver to be used with various frequencies without the need for calibration. In one or more embodiments, the driver compares the pulse widths of a dimmed AC signal to the period of the AC signal to determine the desired light level. The driver may comprise a signal processor and controller in one or more embodiments.
58 Citations
20 Claims
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1. An LED driver comprising:
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an input configured to accept an AC signal; a rectifier in electrical communication with the input, the rectifier configured to rectify the AC signal into a pulse train comprising one or more pulses; a comparator in electrical communication with the rectifier, the comparator configured to utilize a voltage threshold whereby the comparator outputs a first signal while a voltage of the one or more pulses is above the voltage threshold and outputs a second signal while the voltage of the one or more pulses is below the voltage threshold; a controller in electrical communication with the comparator, the controller configured to determine a pulse width of the one or more pulses and a period of the AC signal from the first signal and the second signal whereby the controller is configured to determine a desired level of light output based on a ratio of the pulse width to the period and generate an output signal configured to provide the desired level of light output through LED lighting; and an output configured to provide the output signal to the LED lighting. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An LED driver comprising:
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an input configured to accept an AC signal from a dimmer; a controller configured to compare a voltage of the AC signal to a voltage threshold to determine a pulse width of the AC signal whereby the controller outputs an output signal based on the ratio of the pulse width to a period of the AC signal to provide a desired level of light output through one or more LEDs, the period of the AC signal being at least one preset value stored in the LED driver; and an output configured to provide the output signal to the one or more LEDs whereby the output signal travels through the output to the one or more LEDs. - View Dependent Claims (8, 9, 10, 11)
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12. A method for dimming an LED comprising:
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accepting an AC signal from a dimmer at an input of a dimmable LED driver; comparing one or more voltages of the AC signal to a voltage threshold to determine one or more points where the one or more voltages cross the voltage threshold; identifying one or more pulse widths of one or more pulses in the AC signal, the one or more pulse widths delineated by the time between at least two of the one or more points; identifying a period of the AC signal; determining a desired level of light output based on a ratio between the one or more pulse widths and the period; and based on the ratio, generating an output signal to provide the desired level of light from one or more LEDs. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification