A gate driver for on-line heat-treatment to extend the lifetime of multichip power modules

Abstract:
This paper presents the design and implementation of a gate driver capable to heat and control the temperature of a die in order to e.g. perform an on-line temperature treatment to extend the lifetime of its wire bonds. The so-called ‘active thermal control gate driver’ was implemented in a context of multichip power module with individual gate access. It controls the individual junction temperature of a power die in parallel with other power dies to a defined temperature for any operating conditions, e.g. load, input/output voltages. The defined junction temperature is reached by driving the selected power die in the linear mode rather than in blocked mode during the OFF-state. The linear mode is controlled by modulating the gate-emitter voltage (VGE) value around the threshold value thanks to an online junction temperature measurement feedback and a linear controller. The active driver performances have been evaluated using a multichip power module (PM) into a power converter under several load conditions. The experimental results highlight the proper temperature control of the die by the active gate driver, indeed the junction temperature is controlled with a precision of ±1deg C.