US 6,639,451 B2 · Current reference circuit for low supply voltages

Abstract

A current reference circuit for low supply voltages is provided. The current reference circuit includes a series including a resistor and a diode, a current source having one terminal coupled to a supply voltage and another terminal coupled to the series, an operational amplifier having its negative electrode connected to a band gap reference voltage, and a transistor. The diode has its cathode electrode coupled to ground and its anode electrode coupled to the resistor. The transistor has its gate electrode coupled to the output of the operational amplifier, its source electrode coupled to ground, and its drain electrode coupled to both the positive electrode of the operational amplifier and the current source. Also provided are an integrated circuit that includes at least one current reference circuit for low supply voltages and a signal processing system that includes at least one current reference circuit for low supply voltages.

Claims24

Dependent claims

A current reference circuit for low supply voltages, said current reference circuit comprising:

a series including a resistor and a diode, the diode having its cathode electrode coupled to ground and its anode electrode coupled to the resistor;
a current source having one terminal coupled to a supply voltage and another terminal coupled to the series;
an operational amplifier having its negative electrode connected to a band gap reference voltage;
and
a transistor having its gate electrode coupled to the output of the operational amplifier, its source electrode coupled to ground, and its drain electrode coupled to both the positive electrode of the operational amplifier and the current source.

2 more elements

An integrated circuit that includes at least one current reference circuit, said current reference circuit comprising:

a series including a resistor and a diode, the diode having its cathode electrode coupled to ground and its anode electrode coupled to the resistor;
a current source having one terminal coupled to a supply voltage and another terminal coupled to the series;
an operational amplifier having its negative electrode connected to a band gap reference voltage;
and
a transistor having its gate electrode coupled to the output of the operational amplifier, its source electrode coupled to ground, and its drain electrode coupled to both the positive electrode of the operational amplifier and the current source.

2 more elements

A signal processing system that includes at least one current reference circuit, said current reference circuit comprising:

a series including a resistor and a diode, the diode having its cathode electrode coupled to ground and its anode electrode coupled to the resistor;
a current source having one terminal coupled to a supply voltage and another terminal coupled to the series;
an operational amplifier having its negative electrode connected to a band gap reference voltage;
and
a transistor having its gate electrode coupled to the output of the operational amplifier, its source electrode coupled to ground, and its drain electrode coupled to both the positive electrode of the operational amplifier and the current source.

2 more elements

Dependencies are inferred from the claim text.

Current reference circuit for low supply voltages

Life of this patent

Current reference circuit for low supply voltages

Life of this patent

Abstract

Claims24