Apparatus and method for digitally-controlled automatic gain amplification

An apparatus comprising:

• an input node configured to receive an input signal;
• an output node;
• a programmable gain amplifier (PGA) having an input electrically coupled to the input node, and an output electrically coupled to the output node, the PGA being configured to amplify the input signal with an adjustable gain;
• and
• a gain control block having an input electrically coupled to the input node, the gain control block being configured to adjust the gain of the PGA based at least partly on an observed amplitude envelope of the input signal from the input node such that the PGA generates an output signal with a substantially constant amplitude envelope to the output node,
• wherein the PGA comprise a coarse gain adjustment stage and a fine gain adjustment stage coupled in series between the input node and the output node, wherein the coarse gain adjustment stage is configured to modify the gain of the PGA in larger steps than the fine gain adjustment stage.

An apparatus comprising:

• an input node configured to receive an input signal;
• an output node;
• a programmable gain amplifier (PGA) having an input electrically coupled to the input node, and an output electrically coupled to the output node, the PGA being configured to amplify the input signal with an adjustable gain;
• and
• a gain control block having an input electrically coupled to the input node, the gain control block being configured to adjust the gain of the PGA based at least partly on an observed amplitude envelope of the input signal from the input node such that the PGA generates an output signal with a substantially constant amplitude envelope to the output node,
• wherein the gain control block comprises a window comparator having an input configured to receive the input signal, wherein the window comparator is configured to compare the input signal with one or more reference voltages to generate information on the amplitude envelope of the input signal.

An apparatus comprising:

• an input node configured to receive an input signal;
• an output node;
• and
• a programmable gain amplifier (PGA) having an input electrically coupled to the input node, and an output electrically coupled to the output node, the PGA being configured to amplify the input signal with an adjustable gain,
• wherein the PGA comprises a coarse gain adjustment stage and a fine gain adjustment stage coupled in series between the input node and the output node,
• wherein the coarse gain adjustment stage is configured to adjust the gain of the PGA more roughly than the fine gain adjustment stage,
• wherein each of the coarse gain adjustment stage and the fine gain adjustment stage comprises two or more transconductance units, each of the transconductance units being electrically coupled in parallel to one another,
• wherein the PGA is configured to select at least one of the transconductance units of two or more of the coarse gain adjustment stage or the fine gain adjustment stage to provide at least part of the gain of the PGA.