同步脈寬調(diào)制式高分辨力ADC研究

同步V/F轉(zhuǎn)換器由于其輸出頻率的相位調(diào)制特性，以及輸出頻率上限的限制，影響了其分辨力的進(jìn)一步提高。采用電荷平衡與雙斜式原理相結(jié)合的同步V/F轉(zhuǎn)換技術(shù)，可提高其分辨力。該文提出一種基于雙比較器定電壓的同步脈寬調(diào)制新技術(shù)，在定電壓積分的基礎(chǔ)上，通過較高的同步時鐘脈沖自動“微調(diào)”積分時間，實(shí)現(xiàn)了一個周期內(nèi)電荷的充分平衡。通過多周期測量，實(shí)現(xiàn)了各周期內(nèi)電荷動態(tài)平衡調(diào)節(jié)效果。經(jīng)實(shí)驗(yàn)驗(yàn)證和測試表明，分辨力達(dá)5位，最小二乘法擬合線性度優(yōu)于0.005%。It is difficult to elevate resolution higher for Synchronous Voltage-to-Frequency Converter (SVFC) since its phase modulation characteristic and the restrict of output frequency upper limit. There are some approaches to elevate its resolution higher, for example, taking the technique of integrating charge balancing and slope voltage integral. In this paper, a novel principle and implementation technology based on synchronous Pulse-Width-Modulation (SPWM) mode via dual comparators for integral is brought forward. Its basic principle is charge balancing enough within one period via integral between two reference levels, and the integral time can be fine adjusted by higher frequency synchronous clock. Moreover, charge balancing can be dynamicly adjusted within gate time by multi-periods synchronous measurement method. Verifying test indicates that its resolution is better than 5 digits, and linearity referenced to Method of Least Square better than 0.005%.