Abstract: Digital infrared detectors have advantages such as high integration, high anti-interference ability, high transmission bandwidth, high linearity, and high stability, and have been widely used in the field of infrared detection. This article provides a detailed introduction to the design and implementation of the imaging circuit for the medium wave infrared 640×512 digital detector. This imaging processing circuit provides power, bias voltage, and driving signals to the focal plane to enable it to function properly. Due to the differences in digital readout circuits, different detector cores need to independently adjust bias voltages of different amplitudes to work in the optimal state. In order to improve efficiency and practicality, this article uses FPGA chips to control DACs to provide bias voltages for detectors. This method is designed to meet the working requirements of adjustable bias voltage for digital detectors. It can quickly locate the optimal working state of the detector focal plane readout circuit with an adjustment accuracy of 1.22mV, which increases engineering practicality, ensures high uniformity of the imaging original image, and improves image quality.