US 6,724,260 B2 · Low power current feedback amplifier

Abstract

A low power current feedback amplifier having a lower output impedance input stage is provided. To reduce the output impedance, an input stage comprises a closed-loop input buffer. An exemplary input buffer comprises a closed-loop current feedback amplifier configured within the overall current feedback amplifier, wherein the output of the input buffer corresponds to the inverting node of the overall current feedback amplifier. The closed-loop configuration of the input buffer is facilitated by the use of an internal feedback resistor coupled from an inverting input terminal of the input buffer to the output of the input buffer, which corresponds to the inverting input terminal of the overall current feedback amplifier. The closed-loop input buffer realizes a low output impedance since the loop gain reduces the output impedance of the input buffer. With a lower output impedance, the bandwidth of the current feedback amplifier becomes more independent of the gain, even at low current implementations.

Claims26

Dependent claims

A low power current feedback amplifier configured for providing gain independent bandwidth, said current feedback amplifier comprising:

a closed-loop input buffer having a first input terminal configured to provide a non-inverting input terminal for said current feedback amplifier, an output terminal configured to provide an inverting input terminal for said current feedback amplifier, and an internal feedback component coupled between said output terminal and a second input terminal of said closed-loop input buffer;
a first current mirror coupled to said input buffer and configured to mirror current from said input buffer;
a second current mirror coupled to said input buffer and configured to mirror current from said input buffer;
and
an output buffer configured to provide an output signal for said current feedback amplifier.

2 more elements

A current feedback amplifier configured for low power applications, said current feedback amplifier comprising:

an input buffer comprising:
a non-inverting input terminal configured to provide a non-inverting input terminal for said current feedback amplifier;
an inverting input terminal;
an output terminal configured to provide an inverting input terminal for said current feedback amplifier;
an internal feedback component coupled between said output terminal of said input buffer and said second input terminal of said input buffer to provide a closed-loop configuration, wherein said closed-loop configuration is configured to provide a low output impedance at said inverting input terminal of said current feedback amplifier such that bandwidth of said current feedback amplifier is substantially independent of any gain of said current feedback amplifier;
a pair of current mirrors coupled to said input buffer and configured to mirror current from said input buffer;
and
an output buffer configured to provide an output signal for said current feedback amplifier.

5 more elements

An integrated circuit configured with an amplifier circuit comprising a current feedback amplifier configured for low power operation, said current feedback amplifier comprising:

an inverting input terminal and a non-inverting input terminal;
an input buffer comprising a closed-loop feedback amplifier configured to provide a low impedance at said inverting input terminal to provide said current feedback amplifier with a bandwidth substantially independent of a gain configuration of said current feedback amplifier, said input buffer comprising:
a first input terminal configured to provide said non-inverting input terminal for said current feedback amplifier;
an output terminal configured to provide said inverting input terminal for said current feedback amplifier;
and
an internal feedback resistor coupled between said output terminal and a second input terminal of said input buffer;
a first current mirror and a second current mirror coupled to said input buffer and configured to mirror current from said input buffer;
and
an output buffer configured to provide an output signal for said current feedback amplifier.

6 more elements

Dependencies are inferred from the claim text.

Low power current feedback amplifier

Life of this patent

Low power current feedback amplifier

Life of this patent

Abstract

Claims26