Multifunctional Chip for Use in Thermal Analysis of Power Systems

Abstract

Many military electronic systems experience thermal transient pulses, in the sub-second range, during operation. Transient thermal solutions are being developed to address these transient pulses. In order to determine the performance of these thermal solutions, precise measurement of device junction temperature during the pulse is critical. Researchers have been patterning heaters onto chips using high temperature coefficient of resistance materials, thus allowing the use of the heater as a resistance temperature detector (RTD). For a given RTD material, in order to increase the sensitivity, a high resistance value is required; however, this equates to high voltages needed to get high heat fluxes. This work aims to design a test chip which balances between the instrumentation preferring a large resistance and the desire to maintain reasonable input voltages prompting a low resistance. This work demonstrates a novel multi-functional thermal test chip, which consists of 25 high resistance RTDs connected in parallel. This parallel connection strikes the desired balance by allowing a small overall chip resistance while allowing probing on a much higher resistance single RTD. Furthermore, this design allows optional temperature sensing at multiple locations on the chip’s surface, the possibility to create thermal gradients by controlled powering of individual resistors at different locations on the chip’s surface, and uniform heat flux over the entire chip surface.