Patent ID: 7122998

Claim:
A bandgap reference circuit comprising: first, second and third current sources ( 102 , 104 , and 106 ) adjusted to have the same current, the first current source feeding into a first BJT device module (Q 1 ), the second current source feeding into a second BJT device module (Q 2 ) through a first resistor (R 1 ), and the third current source connecting to a grounding voltage supply through a second resistor (R 2 ); a current summing circuit; a first voltage passing unit connecting an output of the first current source as its input and connecting its output to a first end of a third resistor (R 3 ) and a first output of the current summing circuit; a second voltage passing unit connecting an output of the third current source as its input and feeding its output to a first end of a fourth resistor (R 4 ) and a second output of the current summing circuit; a fifth resistor (R 5 ) connecting to a third output of the current summing circuit on a first end and the grounding voltage supply on a second end thereof, wherein a first current through the fifth resistor bears a substantially linear relationship with a summation of a second current through the third resistor and a third current through the fourth resistor, wherein the outputs of the first and second voltage passing units track their respective inputs, and wherein by selecting predetermined values for the first, second, third, fourth, and fifth resistors in conjunction with selections of the first BJT device module and the second BJT device module, a reference voltage of the circuit across R 5 the fifth resistor is independent of temperature variations.