A Supply Voltage Insensitive Two-Transistor Temperature Sensor With PTAT/CTAT Outputs Based on Monolithic GaN Integrated Circuits

Abstract

The article presents a monolithically integrated temperature sensor using a two-transistor (2 T) configuration based on gallium nitride (GaN) metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs). By adjusting the gate size ratio of the depletion-mode (D-mode) device and enhancement-mode (E-mode) device, the output type of the sensor can be converted from proportional to absolute temperature (PTAT) and complementary to absolute temperature (CTAT). Experimental results demonstrate that the 2 T configuration achieves PTAT/CTAT output with high temperature sensitivity (PTAT/CTAT: 15.86/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 10.53 mV/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> C) over a wide temperature range of 25 °C–250 °C and a broad supply voltage range of 8–60 V, attributed to the superior characteristics of the GaN transistor. In addition, the integrated over-temperature protection (OTP) block based on this temperature sensor has been fabricated in the laboratory, which features a fast response time (381 ns at 150 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> C). These results demonstrate the viability of on-chip integrated sensors in OTP circuits that are fully compatible with 48 V applications and a high-temperature environment, paving the way for the development of high-power density all-GaN smart power systems.