Automatic Gain Control amplifier (AGC) with feedback loop is proposed. As a variable gain amplifier, we use bandpass amplifier. Automatic gain control is carried out by changing the current cutoff angle of the amplifier. We control the current cutoff angle by measuring power of output signal with the help of peak detector in low signal mode. Supportive amplifier allows us to achieve more tuning flexibility. Required gain tuning range is obtained by changing gain ration of the supportive amplifier. We propose a design algorithm of the AGC system. The algorithm is based on the Sonneborn–Berger score. The proposed method helps to achieve fully analytical computation. To prove algorithm validity, calculations and simulation were carried out.