Low quiescent current linear regulator using combination structure of bandgap and error amplifier

A low quiescent current low dropout linear regulator (LDR) with a combination structure of a bandgap and an error amplifier is presented. The circuitry is achieved with a combined structure which is able to obtain a lower quiescent current, because the current for the specific bandgap reference can be omitted. The transient response enhancement circuit can activate an additional path to control the gate voltage of the pass device which assists in monitoring the variation in the output voltage in the steady state. According to restrictions of the process and the product requirements, this proposed LDR is implemented with high-voltage tolerance double-diffused MOS (DMOS) in a 0.6 μm BCD process. The LDR has a quiescent current of 3 μA and is able to deliver a 50 mA load current.