scholarly journals A Technique for Improving the Precision of the Direct Measurement of Junction Temperature in Power Light-Emitting Diodes

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3113
Author(s):  
Demetrio Iero ◽  
Massimo Merenda ◽  
Riccardo Carotenuto ◽  
Giovanni Pangallo ◽  
Sandro Rao ◽  
...  
Keyword(s):  
Room Temperature ◽  
Light Emitting Diodes ◽  
Voltage Drop ◽  
Junction Temperature ◽  
Light Emitting ◽  
Technological Diversity ◽  
Voltage Variation ◽  
Forward Voltage Drop ◽  
Novel Method ◽  
Sample Heterogeneity

Extending the lifetime of power light-emitting diodes (LEDs) is achievable if proper control methods are implemented to reduce the side effects of an excessive junction temperature, TJ. The accuracy of state-of-the-art LED junction temperature monitoring techniques is negatively affected by several factors, such as the use of external sensors, calibration procedures, devices aging, and technological diversity among samples with the same part number. Here, a novel method is proposed, indeed based on the well-known technique consisting in tracking the LED forward voltage drop when a fixed forward current is imposed but exploiting the voltage variation with respect to room temperature. This method, which limits the effects of sample heterogeneity, is applied to a set of ten commercial devices. The method led to an effective reduction of the measurement error, which was below 1 °C.

A Technique for the Direct Measurement of the Junction Temperature in Power Light Emitting Diodes

2020 ◽  
pp. 1-1
Author(s):  
Demetrio Iero ◽  
Massimo Merenda ◽  
Sonia Polimeni ◽  
Riccardo Carotenuto ◽  
Francesco G. Della Corte
Keyword(s):  
Direct Measurement ◽  
Light Emitting Diodes ◽  
Junction Temperature ◽  
Light Emitting

Development of 1200 V, 3.7 mΩ-cm2 4H-SiC DMOSFETs for Advanced Power Applications

2012 ◽  
Vol 717-720 ◽  
pp. 1059-1064 ◽  
Author(s):  
Sei Hyung Ryu ◽  
Lin Cheng ◽  
Sarit Dhar ◽  
Craig Capell ◽  
Charlotte Jonas ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Room Temperature ◽  
Voltage Drop ◽  
Drain Current ◽  
Subthreshold Swing ◽  
Active Area ◽  
Gate Bias ◽  
Forward Voltage ◽  
Recent Developments ◽  
Forward Voltage Drop

We present our recent developments in 4H-SiC power DMOSFETs. 4H-SiC DMOSFETs with a room temperature specific on-resistance of 3.7 mΩ-cm2 with a gate bias of 20 V, and an avalanche voltage of 1550 V with gate shorted to source, was demonstrated. A threshold voltage of 3.5 V was extracted from the power DMOSFET, and a subthreshold swing of 200 mV/dec was measured. The device was successfully scaled to an active area of 0.4 cm2, and the resulting device showed a drain current of 377 A at a forward voltage drop of 3.8 V at 25oC.

scholarly journals Numerical Simulation on Electrical-Thermal Properties of Gallium-Nitride-Based Light-Emitting Diodes Embedded in Board

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Xing-ming Long ◽  
Rui-jin Liao ◽  
Jing Zhou
Keyword(s):  
Finite Element ◽  
Gallium Nitride ◽  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Thermal Characteristics ◽  
Junction Temperature ◽  
Current Crowding ◽  
Total Thermal Resistance ◽  
Light Emitting ◽  
Packaging Structure

The electrical-thermal characteristics of gallium-nitride- (GaN-) based light-emitting diodes (LED), packaged by chips embedded in board (EIB) technology, were investigated using a multiphysics and multiscale finite element code, COMSOL. Three-dimensional (3D) finite element model for packaging structure has been developed and optimized with forward-voltage-based junction temperatures of a 9-chip EIB sample. The sensitivity analysis of the simulation model has been conducted to estimate the current and temperature distribution changes in EIB LED as the blue LED chip (substrate, indium tin oxide (ITO)), packaging structure (bonding wire and chip numbers), and system condition (injection current) changed. This method proved the reliability of simulated results in advance and useful material parameters. Furthermore, the method suggests that the parameter match on Shockley's equation parameters, Rs, nideal, and Is, is a potential method to reduce the current crowding effect for the EIB LED. Junction temperature decreases by approximately 3 K to 10 K can be achieved by substrate thinning, ITO, and wire bonding. The nonlinear-decreasing characteristics of total thermal resistance that decrease with an increase in chip numbers are likely to improve the thermal performance of EIB LED modules.

Room temperature thermo-electric pumping in mid-infrared light-emitting diodes

2013 ◽  
Vol 103 (18) ◽  
pp. 183513 ◽  
Author(s):  
Parthiban Santhanam ◽  
Duanni Huang ◽  
Rajeev J. Ram ◽  
Maxim A. Remennyi ◽  
Boris A. Matveev
Keyword(s):  
Room Temperature ◽  
Light Emitting Diodes ◽  
Infrared Light ◽  
Thermo Electric ◽  
Mid Infrared ◽  
Light Emitting

Room-temperature light-emitting diodes with Ge islands

2000 ◽  
Vol 3 (5-6) ◽  
pp. 383-387 ◽  
Author(s):  
L Vescan ◽  
O Chretien ◽  
T Stoica ◽  
E Mateeva ◽  
A Mück
Keyword(s):  
Room Temperature ◽  
Light Emitting Diodes ◽  
Light Emitting

Study the Effect of Junction Temperature on the Peak Wavelength in GaN-Based High-Power Green Light Emitting Diodes

2011 ◽  
Vol 399-401 ◽  
pp. 1034-1038
Author(s):  
Rong Rong Zhuang ◽  
Ping Cai ◽  
Jiang Li Huang
Keyword(s):  
High Power ◽  
Temperature Rise ◽  
Light Emitting Diodes ◽  
Green Light ◽  
Red Shift ◽  
Junction Temperature ◽  
Spectral Peak ◽  
Peak Wavelength ◽  
Drive Current ◽  
Light Emitting

The junction temperature of GaN-based high-power green light emitting diodes is measured using the temperature coefficients of the diode forward voltage, from changes in temperature and changes in drive current to measure the LED junction temperature and the corresponding spectral, Respectively. Experiments show that, junction temperature due to environmental temperature increased, and the red shift of the spectral peak wavelength. When low temperature or less then the rated current range, the drive current increased in junction temperature rise due to the spectral peak wavelength blue shift . When the current is increased in the range of close to or greater than the rated current, leading to the junction temperature rise will cause spectral red shift . The peak wavelengths’ shift degree of 0.0579nm / k, 0.0751 nm / k and-0.1974nm / k, -0.0915 nm / k are calculated in both cases. The phenomenon is due to the LED junction temperature increases lead to band gap shrinkage, and the result of the role of spontaneous polarization and piezoelectric polarization in Ⅲ-nitride semiconductor materials.

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