Patent ID: 7071767

Claim:
A reference circuit comprising: a first bipolar transistor that exhibits a first voltage drop V BE1 ; a second bipolar transistor that exhibits a second voltage drop V BE2 ; a first resistor having a resistance R 1 , the first resistor being configured to draw a first current proportional to (V BE1 −V BE2 )/R 1 ; a second resistor having a resistance R 2 , the second resistor being configured to draw a second current proportional to V BE1 /R 2 ; a first transistor configured to supply the first and second currents; and a second transistor configured in a current mirror circuit with the first transistor, wherein the second transistor provides a reference current proportional to (V BE1 −V BE2 )/R 1 +V BE1 /R 2 . a third resistor having a resistance R 3 and being coupled in parallel with the first bipolar transistor, the third resistor being configured to draw a third current proportional to V BE1 /R 3 , wherein the third resistance R 3 is greater than the second resistance R 2 ; a third transistor configured to supply current to the third resistor and the first bipolar transistor; and an operational amplifier having input terminals coupled to drains of the first and third transistors, and an output terminal coupled to gates of the first, second and third transistors.