关键词: ADC, 单斜, 分段电容, 失调校准, 轨到轨

Abstract: The single-slope ADC proposed in this paper is applied to the three-dimensional imaging laser focal plane readout circuit, which converts the voltage analog signal detected by the readout circuit into a digital signal for subsequent signal processing. According to the focal plane array specifications, the signal accuracy and speed requirements, we choose single-slope ADC. Because the ramp generator and counter can be shared by all columns, only one comparator and registers is needed per column. The ramp generator uses a split-capacitor array structure, which greatly reduces the chip area. We also calibrate the comparator offset due to high accuracy requirement of the ADC and propose a new structure that increases input range of comparator to rail-to-rail. The ADC proposed in this paper is based on 0.18μm CMOS process, the quantization precision is 12 bits with input voltage quantization range 1.1 V, and the conversion speed is 5 kHz.

Key words: ADC, single-slope, split-capacitor, offset calibration, rail-to-rail