Programmable gain amplifier

A programmable gain amplifier that is configured to receive an input voltage signal and provide an output voltage signal, wherein the programmable gain amplifier comprises:

• a transconductance amplifier, which is configured to receive the input voltage signal and provide a transconductance amplifier current signal, wherein the transconductance amplifier comprises a switchable resistance network that is configurable to set the gain of the programmable gain amplifier;
• a switch leakage compensation circuit, which is configured to receive the input voltage signal and output a compensation current signal, wherein the switch leakage compensation circuit comprises a compensation transconductance amplifier, and wherein the compensation transconductance amplifier comprises a switchable compensation resistance network;
• a transimpedance amplifier, which is configured to provide the output voltage signal based on the difference between the transconductance amplifier current signal from the transconductance amplifier and the compensation current signal from the switch leakage compensation circuit;
• wherein:
• the switchable resistance network comprises a plurality of branches in parallel with each other, wherein each branch includes:
• a gain-setting switch that is openable and closable in accordance with a switch control signal to influence the gain of the programmable gain amplifier;
• and
• a resistance in series with the gain-setting switch;
• the switchable compensation resistance network comprises a plurality of branches in parallel with each other, wherein each branch includes:
• a gain-mimicking switch that has a corresponding gain-setting switch in the switchable resistance network, wherein the gain-mimicking switch is openable and closable in accordance with the same switch control signal that is used for the corresponding gain-setting switch;
• and
• a leakage-current-conducting switch in series with the gain-mimicking switch, wherein the leakage-current-conducting switch is openable and closable in accordance with the complement of the switch control signal that is used to control the gain-mimicking switch in the same branch such that when the gain-mimicking switch in the branch is open, the leakage-current-conducting switch in the branch is closed, and vice versa.