Investigation of Different Integrated Temperature Monitoring Sensors for High-Voltage SoC DC-DC Converters

This paper presents the design and implementation of three types of integrated temperature sensors in 0.18-µm SOI XFAB process. The presented sensors are used to monitor the thermal impact of electrical activity in an integrated system- on-chip (SoC)-based DC-DC converter. Both conduction and switching losses in integrated high-power half-bridge devices embedded in the DC-DC converter generate considerable heat. The latter is monitored by three on-chip temperature sensors based on: a ring oscillator, a voltage threshold measurement, and a diode drop potential measurement. Simulation results show the proper functionality of the implemented circuits. In addition, the performance of the ring oscillator-based sensor is modeled to characterize and allow mitigating the impact of process variations on the temperatures measured with it.