A robust smart power bandgap reference circuit for use in an automotive environment

In junction-isolated smart power technologies, negative voltages at the drain terminal of a power DMOS lead to minority carrier injection into the substrate. This can cause malfunction of sensitive circuits such as bandgap references and may subsequently lead to severe functional failures of the device. Furthermore, in smart power ICs, very high chip temperatures can occur due to excessive power dissipation on- or off-chip in fault conditions. In such cases, the operation of a bandgap reference must be guaranteed to ensure safe shutdown of the device even at excessive chip temperatures. In this paper, a robust bandgap circuit for the use in smart power ICs is presented. It is insensitive to minority carrier injection into the substrate and operates reliably up to temperatures of 260°C