LED drive for generating constant light output
First Claim
1. A power supply for a light emitting diode (LED) light source, comprising:
- an LED power converter adapted to receive power from a power source and to generate an output power signal that can be applied to an LED light source having an effective operating lifetime and an effective light output; and
an LED power controller connected to the LED power converter and adapted to control the output power signal so that it compensates for degradations in the effective light output of the LED light source and ensures that light output by the LED light source when it is connected to the LED power converter remains relatively constant over the effective operating lifetime of the LED light source,wherein the LED power converter is further adapted to;
receive a low frequency ac power signal;
convert the low frequency ac power signal into a dc power signal;
convert the dc power signal into a high frequency ac power signal; and
convert the high frequency ac power signal into the output power signal.
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Accused Products
Abstract
An LED light source drive includes an LED current generating circuit and an LED drive controller. The current generating circuit is operable to receive power from a power source and to generate a dc current that can be used to the drive an LED light source. The drive controller is operable to control the dc current to ensure that the light output of the light source remains approximately constant over its operating lifetime. In one embodiment, the drive controller ensures that the effective light output of the light source remains approximately constant by automatically increasing the dc current in predetermined amounts at predetermined times. In an alternative embodiment, the drive controller includes an LED light sensor that is operable to generate a light signal indicative of the effective light output of the light source and the controller uses this light signal to control the dc current output.
50 Citations
14 Claims
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1. A power supply for a light emitting diode (LED) light source, comprising:
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an LED power converter adapted to receive power from a power source and to generate an output power signal that can be applied to an LED light source having an effective operating lifetime and an effective light output; and an LED power controller connected to the LED power converter and adapted to control the output power signal so that it compensates for degradations in the effective light output of the LED light source and ensures that light output by the LED light source when it is connected to the LED power converter remains relatively constant over the effective operating lifetime of the LED light source, wherein the LED power converter is further adapted to; receive a low frequency ac power signal; convert the low frequency ac power signal into a dc power signal; convert the dc power signal into a high frequency ac power signal; and convert the high frequency ac power signal into the output power signal. - View Dependent Claims (2, 3, 4)
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5. A light emitting diode (LED) light source control system, comprising:
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an LED current converter adapted to receive current from a current source and to generate a current signal that can be supplied to an LED light source having an effective operating lifetime and an effective light output, wherein the LED current converter is further adapted to generate a high frequency ac power signal and to convert the high frequency ac power signal into the current signal; an LED light sensor adapted to receive light output by the LED light source and to generate a light signal based on the light output; and an LED controller connected to the LED current converter and the LED light sensor, the LED controller adapted to adjust the current signal output by the LED power converter based on the light signal so that the current signal compensates for degradations in the effective light output of the LED light source and maintains the light output by the LED light source at a relatively constant level over the effective operating lifetime of the LED light source, wherein the LED controller further adapted to increase the current signal by increasing the frequency of the high frequency ac power signal. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A power supply for a light emitting diode (LED) light source, comprising:
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an LED power converter adapted to receive power from a power source and to generate an output power signal that can be applied to an LED light source having an effective operating lifetime and an effective light output; and an LED power controller connected to the LED power converter and adapted to control the output power signal so that it compensates for degradations in the effective light output of the LED light source and ensures that light output by the LED light source when it is connected to the LED power converter remains relatively constant over the effective operating lifetime of the LED light source, wherein the LED power converter is further adapted to; receive a dc power signal; convert the dc power signal into a high frequency ac power signal; and convert the high frequency ac power signal into the output power signal. - View Dependent Claims (12, 13, 14)
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Specification