Programmable gain amplifier

A programmable gain amplifier, comprising:

• an active load module comprising a first load end and a second load end, and the second load end of the active load module being electrically connected to an output end of the programmable gain amplifier;
• a first differential pair comprising a first input end, a second input end, a first current source end, a first output end and a second output end, the first output end of the first differential pair being electrically connected to the second load end of the active load module, the second output end of the first differential pair being electrically connected to the first load end of the active load module, the first input end of the first differential pair being configured to receive an input signal, and the second input end of the first differential pair being configured to receive a common mode voltage;
• a second differential pair comprising a third input end, a fourth input end, a second current source end, a third output end and a fourth output end, the third output end of the second differential pair being electrically connected to the first load end of the active load module, the fourth output end of the second differential pair being electrically connected to the second load end of the active load module, the third input end of the second differential pair being electrically connected to the output end of the programmable gain amplifier and being configured to receive a feedback signal, and the fourth input end of the second differential pair being configured to receive the common mode voltage;
• and
• a power source module electrically connected to the first current source end of the first differential pair and the second current source end of the second differential pair, the power source module being configured to supply a first current to the first differential pair through the first current source end of the first differential pair, the power source module being configured to supply a second current to the second differential pair through the second current source end of the second differential pair, and the power source module being configured to adjust a current potential of the first current, a current potential of the second current or both.