Design methodology for over-temperature protection of an LDO voltage regulator by using electro-thermal simulations

This paper presents a design methodology based on electro-thermal simulations for the over-temperature protection (OTP) of low drop-out voltage regulators (LDO). The OTP monitors the die temperature developed within the LDO and shuts down the circuit when the temperature reaches a set maximum level (the OTP trigger point). The proposed methodology involves running iteratively electrical, thermal and electro-thermal simulations. It addresses two major issues: first, it allows the designer to identify the suitable location of the OTP sensor by considering the temperature distribution within the LDO's power-stage. Second, the OTP trigger point can be set accurately taking into account coupled electro-thermal phenomena, so that the circuit is shut down when any section of the die reaches the maximum allowable temperature. The proposed methodology is validated by measurements performed on an LDO designed using it.