Thermal analysis and optimization of 2.5-D integrated voltage regulator

Integrated voltage regulators (IVRs) promise to improve performance-per-watt for microprocessors and systems-on-chip by reducing supply voltage margins, resistive losses in the power distribution network, and by enabling power management with greater temporal resolution. However, the thermal impact of IVRs has not been well studied, and the methodologies for thermal analysis of analog/digital mixed-signal designs, such as voltage regulators on chip, have not yet been developed. In this paper, we present a thermal analysis methodology for 2.5-D IVR. Our results show that (1) the integrated power inductor is the hottest component in the IVR, and (2) the temperature of the IVR rises rapidly when the power inductor and the circuitries of the IVR chip overlap. In order to address these issues, we propose two design optimization techniques: design block relocation and inductor spreading. Related experiments show the effectiveness of these methods.