Method and system for buffering a reference voltage

A circuit, comprising:

• an amplifier comprising a first input coupled to a reference voltage node;
• a first buffer having an input coupled to an output of the amplifier;
• a second buffer having an input coupled to the output of the amplifier;
• a capacitor;
• and a controller configured to:
• during a first phase of operation:
• form a first closed loop including the amplifier and the first buffer and excluding the capacitor and the second buffer, wherein the first buffer is configured to provide a first analog voltage to a second input of the amplifier, cause the capacitor to sample a voltage difference between an output of the second buffer and the reference voltage node;
• and during a second phase of operation, form a second closed loop including the amplifier, the first buffer, and the capacitor with the sampled voltage difference stored thereon, and excluding the second buffer, wherein the first buffer is configured to provide a second analog voltage to the second input of the amplifier during the second phase of operation, wherein the second buffer operates in an open loop condition during the second phase of operation.

A circuit comprising:

• an amplifier having a first input coupled to a reference voltage node and a second input;
• a first buffer having an input coupled to an output of the amplifier;
• a second buffer having an input coupled to the output of the amplifier;
• a capacitor;
• a first switch coupled between an output of the first buffer and the second input of the amplifier;
• a second switch coupled between the first input of the amplifier and a first terminal of the capacitor;
• a third switch coupled between an output of the second buffer and a second terminal of the capacitor;
• a fourth switch coupled between the second input of the amplifier and the second terminal of the capacitor;
• and
• a fifth switch coupled between the output of the first buffer and the first terminal of the capacitor.