A Radiation-Hardened Overtemperature Protection Circuit Using a Dynamic Comparison Technique

The total-ionizing-dose (TID) effect has different influences on bipolar junction transistors (BJTs), resistors, and MOSFETs, which leads to significant drifts in the overtemperature threshold in the traditional overtemperature protection circuit (OTPC). An OTPC with a dynamic comparison technique is proposed to improve the radiation-hardened capability. The proposed radiation-hardened OTPC employs two identical sensors to monitor the temperature and convert it into voltage for comparison to determine if overtemperature occurs. The voltage drifts caused by TID effects on two sensors vary dynamically and offset each other, so the overtemperature threshold will not drift theoretically. The normalization method is used to process measurement results to get a visual comparison. The measurement results show that the threshold drift of the proposed OTPC is 5.0% lower than that of traditional OTPC at 30 krad(Si), 7.1% lower at 50 krad(Si), and 10.3% lower at 100 krad(Si). Therefore, the proposed OTPC reduces the threshold voltage drifts effectively and has a good radiation-hardened effect.