Proportional to absolute temperature reference circuit and a voltage reference circuit

A temperature independent voltage reference, the circuit comprising:

• a first bipolar transistor arranged to generate a first base-emitter voltage and a first base current and a second bipolar transistor arranged to generate a second base-emitter voltage and a second base current, respective emitters of the first and second bipolar transistors biased at the same voltages;
• a plurality of passive components, coupled to the first and second bipolar transistors, in which the plurality of passive components includes a series arrangement from ground of a first resistive component, a second resistive component, and a third resistive component, and wherein the first resistive component includes a first end that is connected to a base of the first bipolar transistor and a second end that is connected to a base of the second bipolar transistor such that the current through the first resistive component provides a proportional to absolute temperature (PTAT) component determined by a difference in voltages between the respective bases of the first and second bipolar transistors;
• and
• a complementary to absolute temperature (CTAT) component, coupled to the plurality of passive components;
• wherein the circuit is configured to generate a temperature independent output voltage, across the PTAT component developed using the plurality of passive components and the CTAT component;
• and
• the plurality of passive components are configured to compensate for the first and second base currents.

A method of generating a proportional to absolute temperature (PTAT) voltage, the method comprising:

• providing a circuit comprising a first bipolar transistor, a second bipolar transistor and a series arrangement from ground of first, second, and third resistive components, coupled to the first and second bipolar transistors, wherein respective emitters of the first and second bipolar transistors are biased at the same voltages;
• generating, at the first bipolar transistor, a first base-emitter voltage and a first base current and, at the second bipolar transistor, a second base-emitter voltage and a second base current;
• generating a PTAT output voltage, across the first resistive component, which is dependent on a difference in the first and second base-emitter voltages;
• and
• compensating for the first and second base currents by generating offsetting voltages in the second and third resistive components in the series arrangement to compensate for the effect of the first and second base currents on the PTAT output voltage.