US 5,627,456 A · All FET fully integrated current reference circuit

Abstract

An integrated current reference circuit provides a current output with a predetermined temperature coefficient, suitably zero, to provide constant current over temperature variations. The circuit is formed of only Field Effect Transistors (FETs), allowing the circuit to be implemented using conventional CMOS fabrication techniques. A current mirror provides a reference current in both branches of the circuit. The output of the current mirror is coupled to a circuit providing an imbalance in resistance between the two branches, and an offsetting imbalance in voltages between the two branches, resulting in a reference current that has a predetermined temperature coefficient. An output current is provided which is proportional to the reference current and thus has the same temperature coefficient as the reference current.

Claims5

Dependent claims

A current reference circuit for providing a predetermined current output with a predetermined temperature coefficient, comprising:

a first voltage supply, a ground node, and an output node;
a current mirror, coupled to the first voltage supply, for providing a reference current of equal magnitude in each of two branches of the circuit;
control means, coupled between the current mirror and the ground node, for compensating for variations in one branch with corresponding variations in the other branch, to provide the reference current in each branch with the predetermined temperature coefficient;
and
current output means, coupled between the first voltage supply and the output node, and coupled to the current mirror, for providing the current output with the predetermined temperature coefficient:
wherein the circuit is made only from field effect transistors.

3 more elements

Dependencies are inferred from the claim text.

All FET fully integrated current reference circuit

Life of this patent

All FET fully integrated current reference circuit

Life of this patent

Abstract

Claims5