US 2009/0267692 A1 · DIGITALLY VARIABLE GAIN AMPLIFIER USING MULTIPLEXED GAIN BLOCKS

Abstract

A digitally variable gain amplifier comprising a front-end stage, a level shifter stage, and an output amplifier stage. The front-end stage comprises a high gain pre-amplifier and a low gain pre-amplifier driven in parallel by a differential input signal. A coarse gain control is realized by enabling only one pre-amplifiers at a time, while the differential input signal remains connected to the inputs of the disabled pre-amplifier. An attenuator following each pre-amplifier provides fine gain control. The enabled pre-amplifier amplifies the differential input signal and outputs a first dc voltage level. The disabled pre-amplifier is placed into a standby ready mode and outputs a second dc voltage level that is greater in magnitude than the first dc voltage level. The level shifter stage performs a minimum voltage selection operation to automatically select and level shift the amplified differential input signal, and further pass the signal to the output amplifier stage.

Claims20

Dependent claims

A digitally variable gain amplifier, comprising:

a front-end amplification stage comprising a plurality of gain blocks, wherein the plurality of gain blocks are driven in parallel by a differential input signal that is continuously connected to input terminals of each gain block during amplifier operation;
a selection stage configured to receive a signal from each gain block during amplifier operation;
and
an output stage configured to receive and condition a differential signal from the selection stage;
wherein one gain block of the plurality of gain blocks is placed in an active mode to amplify the differential input signal and each remaining gain block of the plurality of gain blocks is placed in a standby ready mode, and wherein the selection stage automatically selects the amplified differential signal from the one gain block that is placed in the active mode from the received signals.

2 more elements

A digitally variable gain amplifier using multiplexed gain blocks, comprising:

a front-end amplification stage comprising a plurality of gain blocks, wherein the plurality of gain blocks are driven in parallel by a differential input signal that is connected to input terminals of each gain block for a duration of amplifier operation;
a selection stage configured to receive an input signal from each gain block during amplifier operation;
and
an output stage configured to receive a differential signal from the selection stage;
wherein one gain block of the plurality of gain blocks is placed in an active mode to amplify and transmit the differential input signal and a first dc voltage level to the selection stage and each remaining gain block of the plurality of gain blocks is simultaneously placed in a standby ready mode to disable signal amplification, wherein a disabled gain block transmits a second dc voltage level to the selection stage, and wherein the selection stage automatically selects the differential input signal from all received signals for transmission to the output stage.

2 more elements

Dependencies are inferred from the claim text.

Digitally variable gain amplifier using multiplexed gain blocks

Life of this patent

Digitally variable gain amplifier using multiplexed gain blocks

Life of this patent

Abstract

Claims20