Fine quantization ramp generator for two-step monoclinic analog-to-digital converter

Abstract

The invention belongs to the technical field of analog-to-digital conversion, and particularly relates to a fine quantization ramp generator for a two-step monoclinic analog-to-digital converter. According to the fine quantization ramp generator, an output buffer module 205 adopts a common-mode invariant mode, so that the problem that the performances such as integral nonlinearity (INL), differential nonlinearity (DNL) and spurious-free dynamic range (SFDR) of the slope generator become poor due to the change of the common-mode level of the output buffer of the slope generator in the establishing process is solved; meanwhile, the problem that substrate parasitic capacitance is introduced into a loop by adopting substrate source short circuit is avoided, and a good effect of improving the linearity of an output signal of the ramp generator is achieved; in addition, a feedforward transconductance path structure and a resistance-capacitance compensation structure are adopted, so that thepurpose of zero-pole cancellation of an operational amplifier of the output buffer module 205 of the fine-quantization ramp generator is achieved, and the linearity, the loop stability and the establishing stabilization time of the output buffer module 205 of the fine quantization ramp generator are optimized.

Description

technical field [0001] The invention belongs to the technical field of analog-to-digital conversion, and in particular relates to a fine-grained ramp generator for a two-step single-slope analog-to-digital converter. Background technique [0002] The slope generator (Single-Slope Generator) is essentially a digital-to-analog converter (DAC, DigitaltoAnalog Converter). Digital-to-analog conversion is to convert the digital signal processed by the system into an analog signal; input a set of digital signals to the digital-to-analog converter The corresponding analog signal is generated by accumulating the weight value of the digital signal by using the reference voltage. A digital-to-analog converter (DAC) plays an important role in converting digital signals into analog signals in the field of image sensing. DAC is currently divided into Nyquist type and oversampling type according to the principle; Nyquist type DAC is mainly divided into resistance type DAC, switched capaci...

AI Technical Summary

Problems solved by technology

[0008] For above-mentioned existence problem or deficiency, in order to solve the change of output buffer common-mode level in the existing refinement ramp generator, the unfavorable influence to the conversion performance of ramp generator; The fine-grained ramp generator of the analog-to-digital converter, whose output buffer adopts the current-current negative feedback structure, uses the fixed low-level VFB voltage (a fixed low level provided externally) as the stable common-mode voltage of the output buffer op-amp connected to its positive input

Images