Dual input self-referenced voltage regulator

A method, comprising:

• generating a regulated voltage at an output based on a first supply voltage on a first voltage rail based on a first condition;
• generating the regulated voltage based on a second supply voltage on a second voltage rail on a second condition;
• and
• decoupling the first voltage rail from the output in response to a third condition.

An apparatus, comprising:

• a first voltage regulator configured to generate a regulated voltage at an output based on a first supply voltage on a first voltage rail;
• a second voltage regulator configured to generate the regulated voltage at the output based on a second supply voltage on a second voltage rail;
• and
• a control circuit configured to:
• couple the first and second voltage rails to the output at the same time in response to a first condition;
• and
• decouple the first voltage rail from the output in response to a second condition.

An apparatus, comprising:

• means for generating a regulated voltage at an output based on a first supply voltage on a first voltage rail based on a first condition;
• means for generating the regulated voltage based on a second supply voltage on a second voltage rail on a second condition;
• and
• means for decoupling the first voltage rail from the output in response to a third condition.