Low supply headroom bandgap voltage reference

A low supply headroom bandgap voltage reference generation circuit for generating a bandgap reference voltage from a supply voltage, the bandgap voltage reference generation circuit comprising:

• a first delta base-to-emitter voltage generation circuit, comprising a first Darlington configuration of a first pair of transistors arranged in a differential pair with a second Darlington configuration of a second pair of transistors, wherein:
• a first input to the first Darlington pair of transistors is connected to an output voltage node of the bandgap voltage reference generation circuit;
• a second input to the second Darlington pair of transistors is connected to the output voltage node of the bandgap voltage reference generation circuit via a first delta base-to-emitter-voltage resistor, wherein a connection between the second input and the first delta base-to-emitter-voltage resistor comprises an intermediate node;
• and
• a base-to-emitter voltage generation circuit, arranged between the intermediate node and a ground node.

A method for operating a low supply headroom bandgap voltage reference circuit for generating a bandgap reference voltage from a supply voltage, the method comprising:

• generating a first current density in a first Darlington configuration of a first pair of transistors;
• generating a second current density in a second Darlington configuration of a second pair of transistors;
• and
• generating a difference in base-to-emitter voltage between the first Darlington configuration and the second Darlington configuration using a first delta base-to-emitter-voltage resistor to produce a proportional-to-absolute temperature current that is used for generating a temperature-stabilized bandgap reference voltage.