Apparatus for Reference Voltage Generating Circuit

A device comprising:

• a first voltage divider coupled between a supply voltage potential and a ground potential, wherein the first voltage divider comprises a plurality of first resistors and a first switch connected in series;
• a second voltage divider connected in parallel with the first voltage divider, wherein the second voltage divider comprises a plurality of second resistors and a second switch connected in series;
• a first output stage including a first transistor and a second transistor connected in series, wherein a first reference voltage is generated at a common node of the first transistor and the second transistor;
• a first amplifier coupled between the first voltage divider and the first output stage;
• a first bias circuit configured to provide a first bias current for the first amplifier;
• a second output stage including a third transistor and a fourth transistor connected in series, wherein a second reference voltage is generated at a common node of the third transistor and the fourth transistor;
• a second amplifier coupled between the second voltage divider and the second output stage;
• and
• a second bias circuit configured to provide a second bias current for the second amplifier.

A system comprising:

• a plurality of input and output buffers comprising a plurality of level shifters;
• a reference voltage bias generator configured to generate a first reference voltage and a second reference voltage for the level shifters, wherein the reference voltage bias generator is configured to:
• operate in a low supply mode when a supply voltage of the reference voltage bias generator is less than a threshold voltage;
• and
• operate in a high supply mode when the supply voltage of the reference voltage bias generator is greater than a threshold voltage;
• and
• a reference voltage booster connected to reference bias signals generated by the reference voltage bias generator, wherein the reference voltage booster is configured to increase drive capability of the reference voltage bias generator when a plurality of input and output interface circuits are coupled to the reference voltage bias generator.