Two-stage audio gain circuit based on analog-to-digital conversion and audio terminal

A two-stage audio gain circuit based on analog-to-digital conversion, comprising:

• a programmable gain amplifier (PGA) configured to receive an analog audio signal and perform programmable gain amplification processing on the received analog audio signal;
• an analog-to-digital converter configured to convert the analog audio signal after the programmable gain amplification processing into a digital audio signal and output the digital audio signal;
• a first automatic gain control (AGC) gain unit configured to perform a first AGC processing on the digital audio signal and output a first gain adjustment value to the PGA, for the PGA to perform gain adjustment on the received analog audio signal according to the first gain adjustment value;
• and
• a second AGC gain unit configured to perform a second AGC processing on the digital audio signal and output a second gain adjustment value to the PGA, for the PGA to perform gain adjustment on the received analog audio signal according to the second gain adjustment value.