Circuitry for low-dropout regulator with overvoltage protection circuit

A process for regulating power supply using a low-dropout regulator, the process comprising:

• monitoring voltage levels by a power detector;
• detecting voltage levels based on a predetermined first voltage level as a high voltage and a second voltage level as a medium voltage, wherein the high voltage and the medium voltage power up at different times, with the high voltage powering up followed by the medium voltage;
• turning on or turning off an overvoltage protection circuit based on the detected voltage levels;
• regulating an output voltage based on a feedback loop utilizing the actual output voltage of a source follower and a predetermined safe voltage as a reference;
• performing shifting bias mechanism when the overvoltage protection circuit is turned on;
• and
• performing a fix bias mechanism when the overvoltage protection circuit is turned off,
• wherein turning on the overvoltage protection circuit when high voltage is detected and turning off the overvoltage protection circuit when medium voltage is detected,
• wherein the shifting bias mechanism comprises lowering an actual bias voltage to counter back the required high bias voltage during the initial power up of the high voltage rail, and applying the actual bias voltage for a feedback system, and
• wherein the fix bias mechanism comprises applying a fixed voltage reference to an actual pass gate of a source follower for the feedback system, enabling an instant startup together with the medium voltage when it powers up.