Temperature measurement and control for laser and light-emitting diodes
First Claim
1. A method of operating an emission diode for junction temperature determination, comprising:
- characterizing the emission diode by measuring an operating temperature of the emission diode when producing emissions at a predetermined wavelength;
setting a target operating temperature equal to the measured operating temperature;
providing a drive current to the emission diode at a level sufficient to enable emissions by the emission diode;
removing the drive current from the emission diode;
providing a reference current to the emission diode at a level less than the drive current level after removing the drive current from the emission diode;
determining a forward voltage level of the emission diode under application of the reference current; and
controlling an operating temperature of the emission diode based on the forward voltage level and the target operating temperature.
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Accused Products
Abstract
The existing diodes in an LED or laser diode package are used to measure the junction temperature of the LED or laser diode. The light or laser emissions of a diode are switched off by removing the operational drive current applied to the diode package. A reference current, which can be lower the operational drive current, is applied to the diode package. The resulting forward voltage of the diode is measured using a voltage measurement circuit. Using the inherent current-voltage-temperature relationship of the diode, the actual junction temperature of the diode can be determined. The resulting forward voltage can be used in a feedback loop to provide temperature regulation of the diode package, with or without determining the actual junction temperature. The measured forward voltage of a photodiode or the emissions diode in a diode package can be used to determine the junction temperature of the emissions diode.
204 Citations
19 Claims
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1. A method of operating an emission diode for junction temperature determination, comprising:
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characterizing the emission diode by measuring an operating temperature of the emission diode when producing emissions at a predetermined wavelength; setting a target operating temperature equal to the measured operating temperature; providing a drive current to the emission diode at a level sufficient to enable emissions by the emission diode; removing the drive current from the emission diode; providing a reference current to the emission diode at a level less than the drive current level after removing the drive current from the emission diode; determining a forward voltage level of the emission diode under application of the reference current; and controlling an operating temperature of the emission diode based on the forward voltage level and the target operating temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An emission diode driver, comprising:
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at least one current source, the at least one current source supplies a drive current for an emission diode coupled to the emission diode driver and a reference current for the emission diode; at least one voltage measurement circuit, the at least one voltage measurement circuit measures a forward voltage of the emission diode while the reference current is applied to the emission diode; and at least one control circuit that controls an operating temperature of a diode package based on the measured forward voltage of the emission diode and a target operating temperature that is equal to a characterized operating temperature of the emission diode when producing emissions at a predetermined wavelength. - View Dependent Claims (14, 15, 16)
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17. A method of operating an emission diode in a diode package with a photodiode, comprising:
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characterizing the emission diode package by measuring an operating temperature of the emission diode when producing emissions at a predetermined wavelength; setting a reference forward voltage for the photodiode based on the measured operating temperature of the emission diode; providing a drive current to the emission diode at a level sufficient to enable emissions by the emission diode; removing the drive current from the emission diode; providing a reference current to the photodiode at a level less than the drive current level after removing the drive current from the emission diode; determining a forward voltage level of the photodiode under application of the reference current; and controlling an operating temperature of the emission diode based on comparing the forward voltage level of the photodiode to the reference forward voltage. - View Dependent Claims (18, 19)
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Specification