A very low quiescent current linear voltage regulator with wide input voltage and wide load current range for automotive applications

This paper presents a very low quiescent current linear voltage regulator meant to supply a microcontroller in an automotive ECU. This is a 3 pins device which is always connected to battery, even when car’s engine is off and therefore a very low total current consumption for the block is desired. The regulator has a fixed 5V output voltage and a 0.5A maximum load current The proposed regulator, implemented in a 0.8µm BiCMOS technology, has a total quiescent current of 3.8µA (no load) and due to an adaptive biasing technique a 75µA is obtained at 500mA. Using a buffer block a PSRR of 65dB at 100Hz is obtained even with this very low quiescent current.