Influence of LED Operating Point and Cooling Conditions on Compact Thermal Model Element Values

Compact thermal models are an essential part of multi-domain models allowing the computation of power LED optical output. This paper, based on a practical example, investigates the dependence of compact thermal model element values on the device operating point and ambient temperature. The presented experiments prove that LED compact thermal models should be always generated taking into account the actual heating power instead of the electrical one. The compact models are derived here from the computed time constant spectra of device heating curves employing the Network Identification by Deconvolution method. Owing to this approach it is possible to assign some physical meaning to compact thermal model element values.