Mid-wave infrared (MWIR) HgCdTe detectors operating at room temperature face challenges in enhancing signal-to-noise ratio (SNR) and dynamic range during signal readout owing to their low impedance and high background currents, which limit their practical applicability under noncooled conditions. This paper presents a light-to-frequency converter circuit architecture designed to address these limitations. The proposed circuit stabilizes the detector’s operating state using a low-offset operational amplifier and employs a current-to-voltage-to-current-to-frequency conversion process to reduce the high photocurrent into a range suitable for the current–frequency input stage (0 to 4.3 μA). Additionally, the circuit effectively suppresses dark and background currents originating from the detector. Experimental results demonstrate that the integrated system achieves a dynamic range of 93 dB with a power consumption of only 27.3 mW, enabling room-temperature, large-dynamic-range readout for MWIR HgCdTe detectors.