A low voltage CMOS over-temperature protection circuit with MOSFETs working in the sub-threshold region

A CMOS over-temperature protection(OTP) circuit working in sub-threshold region is proposed in this paper, which uses sub-threshold MOSFETs as a substitute for BJTs to sense the temperature, significantly reducing the quiescent current down to 5µA. It also improves the compatibility of the circuit, since it can be manufactured in standard CMOS process. The low voltage wide-swing cascode current mirror minimizes the impact of supply voltage variations on the OTP threshold, achieving a temperature threshold variation of just 0.1275°C, at a supply voltage of 1.5V–7V.