A High SNR Improvement CMOS Analog Accumulator with Charge Compensation Technique

In this paper, a 7.75 kHz line rate analog domain time delay integration (TDI) CMOS analog accumulator with 128-stage is proposed. An adaptive compensation for the charge loss due to parasitic effects is adopted. Based on the influence mechanism of parasitic effects, alternately charging the top and bottom plates of the storage capacitor while cooperate positive feedback capacitor dynamically compensates for the charge loss of the sampling phase and the holding phase. Using the proposed circuit, after the post-layout simulation verification, the SNR of 128 stage accumulation can be improved by as much as 20.9 dB.