Temperature measurement and control for laser and light-emitting diodes
First Claim
1. A circuit, comprising:
- an emission diode;
a photodiode;
a voltage measurement circuit configured to measure at least one of a forward voltage of the emission diode or a forward voltage of the photodiode; and
a control circuit configured to control an operating temperature of the emission diode based on the at least one measured forward voltage and a target operating temperature that is equal to a characterized operating temperature of the emission diode when producing emissions at a predetermined wavelength.
2 Assignments
0 Petitions
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.
194 Citations
20 Claims
-
1. A circuit, comprising:
-
an emission diode; a photodiode; a voltage measurement circuit configured to measure at least one of a forward voltage of the emission diode or a forward voltage of the photodiode; and a control circuit configured to control an operating temperature of the emission diode based on the at least one measured forward voltage 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 (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A circuit, comprising:
-
an emission diode; a current source coupled to the emission diode, the current source configured to switchably supply a drive current and configured to supply a reference current; a voltage measurement circuit configured to measure a forward voltage of the emission diode; and a control circuit configured to control an operating temperature of the emission diode 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 (11, 12, 13, 14)
-
-
15. A circuit, comprising:
-
an emission diode; a photodiode; a current source coupled to the emission diode, the current source configured to switchably supply a drive current for the emission diode and configured to switchably supply a reference current for the photodiode; a voltage measurement circuit configured to measure a forward voltage of the photodiode; and a control circuit configured to control an operating temperature of the emission diode based on the measured forward voltage of the photodiode 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 (16, 17, 18, 19, 20)
-
Specification