Voltage regulator with controlled current consumption in dropout mode

A voltage regulator, comprising:

• an input terminal configured to receive an input voltage;
• an output terminal configured to supply an output voltage;
• a power transistor having a first conduction terminal coupled to the input terminal, a second conduction terminal coupled to the output terminal, and a control terminal;
• a differential amplifier having:
• a first stage with a first input configured to receive a reference voltage, a second input configured to receive a feedback voltage derived from the output voltage, and an output configured to provide a drive signal based on a first difference in voltage between the reference voltage and the feedback voltage;
• and
• a second stage with a driver circuit comprising a variable impedance circuit coupled to the control terminal of said power transistor, and a driver transistor having a first conduction terminal coupled to the control terminal of said power transistor, and a control terminal configured to receive the drive signal;
• and
• a dropout detector and quiescent current limiter circuit configured to sense a second difference in voltage between a voltage of the drive signal and a voltage at the control terminal of said power transistor and modify an impedance of the variable impedance circuit in response to the sensed second difference.