Low power reference voltage circuit

A low power circuit for providing a reference voltage, comprising:

• a bandgap reference circuit, said bandgap reference circuit providing a first Reference voltage in response to a control signal;
• an analog to digital converter coupled to an output of said bandgap reference circuit, said analog to digital converter providing a digital value corresponding to said first reference voltage;
• a data register coupled to an output of said analog to digital converter, said data Register storing said digital value;
• a digital to analog converter coupled to said data register, said digital to analog converter providing a second reference voltage corresponding to said digital value;
• and
• an output switch comprising a first switch coupled to said bandgap reference Circuit output and a second switch coupled to an output of said digital to analog converter,
• wherein said switches are responsive to said control signal to pass said first reference voltage to an output node of said low power circuit when said bandgap reference circuit is enabled and to pass said second reference voltage to said output node after said bandgap reference circuit is disabled.

A method of providing a reference voltage, comprising the steps of:

• generating a first reference voltage with a bandgap reference circuit;
• converting said first reference voltage to a digital signal;
• converting said digital signal into a second reference voltage;
• providing said first reference voltage to an output node for a first period of time;
• and
• after said first period of time, disabling said bandgap reference circuit and providing said second reference voltage to said output node.