High-power
LED thermal resistance calculation
1. Thermal resistance refers to the heat transfer channel between the
two reference points, the temperature difference and heat transfer rate
between two points the ratio of:
Rth = △ T / qx (1)
Where: Rth = thermal resistance between two points (℃ / W or K / W), ΔT
= temperature difference between two points (℃), qx = heat transfer
rate between two points (W).
2. Heat transfer model for thermal resistance calculation
Rth = L / λS (2)
Where: L for the heat conduction distance (m), S for the heat
conduction channel cross-sectional area (m2), λ is thermal conductivity
(W / mK). The shorter the heat conduction distance, the greater the
cross-sectional area and the higher the thermal conductivity
coefficient of thermal resistance reduction of the more favorable, and
this requires well-designed package structure and selection of
appropriate materials.
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