Thermal Resistance Measurement of LED Package with Multichips
27 Nov 2007-IEEE Transactions on Components and Packaging Technologies (IEEE)-Vol. 30, Iss: 4, pp 632-636
TL;DR: In this article, the thermal transient measurements of high-power GaN-based light-emitting diodes (LEDs) with multichip designs are presented and discussed in the literature.
Abstract: Thermal transient measurements of high power GaN-based light-emitting diodes (LEDs) with multichip designs are presented and discussed in the paper. Once transient cooling curve was obtained, the structure function theory was applied to determine the thermal resistance of packages. The total thermal resistance from junction to ambient considering optical power is 19.87 K/W, 10.78 K/W, 6.77 K/W for the one-chip, two-chip and four-chip packages, respectively. The contribution of each component to the total thermal resistance of the package can be determined from the cumulative structure function and differential structure function. The total thermal resistance of multichip packages is found to decrease with the number of chips due to parallel heat dissipation. However, the effect of the number of chips on thermal resistance of package strongly depends on the ratio of partial thermal resistance of chip and that of slug. Therefore, an important thermal design rule for packaging of high power multichip LEDs has been analogized.
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TL;DR: It was found that the thermal improvement of the LED module led to the enhancement of the light output power and radiant intensity and the temperature calibrating factor, 0.046 nm/°C, was calculated from the peak wavelengths of the LEDs modules.
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TL;DR: In this article, a method for creating compact thermal models of single-chip and multi-chip LED package is developed and evaluated with good agreement between the finite volume simulation and experimental data.
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TL;DR: In this article, the authors describe a novel thermal characterization method of GaN-based Light Emitting Diode (LED) package driven under the Alternating Current (AC) mode.
Abstract: In this paper we describe a novel thermal characterization method of GaN-based Light Emitting Diode (LED) package driven under the Alternating Current (AC) mode. The result was compared with the results from the thermal analysis for LED package operated under the Direct Current (DC) condition. Different from the DC condition, the junction temperature rise with the operation time of LED package was exhibited in a band formation. Finite Volume Method (FVM) was utilized to calculate the thermal performance of LED package under the AC condition using the input power extracted from the output current and voltage from the AC power supply. The experimental result was in a good agreement with the simulation data.
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TL;DR: A 3D simulation model has been created and simulated with Comsol Multiphysics software and one LED spot light device with a defected LED module was found in photometric measurements and IR-imaging.
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TL;DR: In this paper, the lateral multifinger-type Schottky barrier diode (SBD) with bonding pad over active structure fabricated on the AlGaN/GaN heterostructure prepared on sapphire substrate was demonstrated.
Abstract: We have demonstrated the lateral multifinger-type Schottky barrier diode (SBD) with bonding pad over active structure fabricated on the AlGaN/GaN heterostructure prepared on sapphire substrate. The fabricated GaN-SBD with size of 9 mm2 exhibited excellent device characteristics such as forward current of 4.5 A at 1.5 V, leakage current of 6 μA at 600 V, and high breakdown voltage of 747 V. The temperature variations of GaN-SBD for the reverse recovery characteristics are negligible and the value of reverse-recovery charge (Q)rr of GaN-SBD is one twentieth of Si-diode at 175°C.
37 citations
Cites background from "Thermal Resistance Measurement of L..."
...so called K factor, which is the thermal calibration factor equal to the reciprocal of the voltage-temperature coefficient for the device under test at a fixed sense current [38]....
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References
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770 citations
"Thermal Resistance Measurement of L..." refers background in this paper
...THE light emitting diode (LED) was first introduced in 1962 [1]....
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TL;DR: In this paper, a deconvolution operation performed in the logarithmic time domain gives the "timeconstant spectrum" of the chip-case-ambient thermal structure.
Abstract: A new method has been developed in order to identify the thermal environment of a semiconductor device chip. The identification algorithm operates on the thermal transient response of the device recorded during a one-shot pulse measurement. A deconvolution operation performed in the logarithmic time domain gives the “time-constant spectrum” of the chip-case-ambient thermal structure. A further transformation leads to the “structure-function” that is the cross-sectional area of the heat conducting materials vs thermal resistance (related to the heat source). The structure function has a good and quantitatively evaluable correspondence to the physical chip environment and heat conducting structure. Separating the different regions of the heat-flow path (corresponding to the chip, bond, header, case) as well as the detection of eventual heat-transport irregularities (mounting errors) is possible.
419 citations
"Thermal Resistance Measurement of L..." refers background in this paper
...evaluation of the T3ster is based on a representation of the distributed RC networks [11], [12]....
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TL;DR: In this article, the key design features of high power light emitting diodes (LEDs) are covered with special emphasis on power packaging, flip-chip device design, and phosphor coating technology.
Abstract: High power light emitting diodes (LEDs) continue to increase in output flux with the best III-nitride based devices today emitting over 150 lm of white, cyan, or green light. The key design features of such products will be covered with special emphasis on power packaging, flip-chip device design, and phosphor coating technology. The high-flux performance of these devices is enabling many new applications for LEDs. Two of the most interesting of these applications are LCD display backlighting and vehicle forward lighting. The advantages of LEDs over competing lighting technologies will be covered in detail.
216 citations
"Thermal Resistance Measurement of L..." refers background in this paper
...After the 1990’s, manufacturers began to produce various high-power LED packages [3]–[5]....
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TL;DR: In this article, the performance of surface-emitting visible AlGaInP light emitting diodes (LEDs) is described and compared with the current state-of-the-art red AlGaAs LEDs.
Abstract: The performance of surface‐emitting visible AlGaInP light‐emitting diodes (LEDs) is described. The devices have external quantum efficiencies greater than 2% and luminous efficiencies of 20 lm/A in the yellow (590 nm) spectral region. This performance is roughly ten times better than existing yellow LEDs and is comparable to the highest performance red AlGaAs LEDs currently available. The devices also perform favorably compared to existing devices in the orange and green spectral regions. Low‐pressure organometallic vapor phase epitaxy (OMVPE) is used to grow the epitaxial layers. The devices consist of a double heterostructure with an AlGaInP active region grown on a GaAs substrate.
210 citations
"Thermal Resistance Measurement of L..." refers background in this paper
...An 8-in integrating sphere (Labsphere) is used for measuring optical power of LEDs....
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...Therefore, the junction temperatures of LEDs significantly influence the reliability and durability [8]....
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...The schematic structure of high power GaN-based LEDs is shown in Fig....
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...Early LEDs were used primarily in indicator-lighting applications....
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...In the early 1990 s, improvements in materials and crystal-growth techniques enabled the production of high-bright LEDs [2]....
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TL;DR: In this paper, the dipole intensity function and the time-constant density of RC one-port networks are introduced for the identification and synthesis of distributed RC networks, and the results can also be applied directly for inductance-resistance networks.
Abstract: Representations of infinite distributed RC one-ports are described. Two functions are introduced: the dipole intensity function (as the generalization of pole-zero pattern) and the time-constant density (as the generalization of the discrete time-constant set of a lumped network). Relations between these representations and the complex impedance are presented. These representations can be regarded as the generalization of the descriptions commonly used in the theory of lumped networks. The representations offer possibilities for the identification and for the synthesis of distributed RC networks. Although the representations were introduced for the case of RC networks, the results can also be applied directly for inductance-resistance networks. The use of the new representations is demonstrated by some examples. >
163 citations