Junction temperature control of UV-C LEDs based on a thermoelectric cooler device

A combined solution of thermoelectric coolers and microchannels for multi-chip heat dissipation with precise temperature uniformity control

With the development of high-power light-emitting diodes (LEDs), the heat flux density of devices has continued to increase, which, in turn, requires the development of increasingly effective methods of heat dissipation to control the working temperature of LEDs. Due to their impressive performance in solid refrigeration and energy harvesting, thermoelectric devices such as thermoelectric coolers (TECs) and thermoelectric generators (TEGs) have been used to develop the methods of heat dissipation, which have been applied to power components and electronic devices. This article proposes a delayed electrothermal collaborative cooling system based on a TEC–TEG system that uses an auxiliary charging technique for energy harvesting. In the designed delay circuit, two power source rails containing a TEG and a charged capacitor are switched automatically to supply energy to a TEC according to the charge on the capacitor and the discharge time of the delay circuit used for energy transmission. The results of experiments show that using the proposed scheme, the electromotive force can be increased by 21.6%, from 0.37 to 0.45 V, in the TEG module compared with the collaborative electrothermal cooling system without auto-delayed power rail switching. The switching time cost of the proposed system was only 0.8 s, and it could continuously supply enough electromotive force to drive the TEC and the overall cooling system. The proposed electrothermal collaborative cooling system with delayed power rail switching and auxiliary charging can improve energy utilization and reduce device cost, which helps to efficiently manage heat dissipation in high-power LEDs.

Electrothermal Collaborative Cooling With Delayed Power Rail Switching Auxiliary Charging by Considering Energy Harvesting Mechanism for High-Power LEDs

Effects of multi-factors on the junction temperature of LED automotive lamp chips

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Estimation of the Ultraviolet-C Doses from Mercury Lamps and Light-Emitting Diodes Required to Disinfect Surfaces

A thermoelectric control system using thermoelectric cooler devices, allows to improve considerably the optical performance of deep UV LEDs operating at desired temperatures. Such a system was implemented monitoring and controlling temperature and optical intensities.

Improving the Optical Performance and Life Time of Deep UV LEDs by Thermoelectric Control

This chapter intends to name and describe briefly the most important groups of techniques used in neuroscience. Two groups of techniques are discussed in more detail: electrophysiologic and imaging methods for being particularly important in neuroscience and for being of special interest for psychologists. Ideally, the reader should be informed about the potential and the shortcomings of the diverse methods, from the physical background to economic considerations. A special effort has been made to describe and explain the modern imaging techniques, particularly magnetic resonance imaging, for being of outstanding importance in cognitive neuroscience and, hence, in psychology.

Tools of Neuroscience

A thermoelectric control system using thermoelectric cooler devices (TEC) combined with an aluminum heat dissipater and a fan heat extractor allows improving considerably the optical performance of deep UV LEDs (285 nm) operating at desired temperatures. A proportional, integral, and differential controller (PID) control technique was implemented to control the voltage in the TEC devices, and therefore, the desired range of temperatures can be achieved. The PID parameters are obtained with computational simulations based on physical models and experimental data recordings of the temperature, using a thermistor sensor for the temperature measurements and SiC photodiode with UV enhanced system for the optical power measurements. The experimental data show that decreasing the temperature of the UV-C LED light source using a TEC increases the optical output power, while it has been shown that the lifetime of the LED devices can be improved.

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Pablo Fredes

Papers

Junction temperature control of UV-C LEDs based on a thermoelectric cooler device

Estimation of the Ultraviolet-C Doses from Mercury Lamps and Light-Emitting Diodes Required to Disinfect Surfaces

Improving the Optical Performance and Life Time of Deep UV LEDs by Thermoelectric Control

Tools of Neuroscience

Thermoelectric Control of Deep UV LED to Improve Optical Performance