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一種低功耗電流/頻率轉(zhuǎn)換電路零偏補償方法
電子技術(shù)應(yīng)用 2023年7期
汪金華,游超,莊永河,楊楊,李鴻高,吳向東
(中國電子科技集團公司第四十三研究所 微系統(tǒng)安徽省重點實驗室,安徽 合肥230088)
摘要: 電流/頻率轉(zhuǎn)換電路主要用于慣導(dǎo)領(lǐng)域中加速度計輸出電流測量,目前典型電流/頻率轉(zhuǎn)換電路功耗較大,限制了其應(yīng)用范圍。通常采用分流電路進行低功耗電流/頻率轉(zhuǎn)換電路設(shè)計,但該方式會帶來較大零偏誤差,影響電路測量精度。對此分析了影響低功耗電流/頻率轉(zhuǎn)換電路零偏的原因,提出了一種利用單片機實現(xiàn)零偏補償?shù)姆椒?,其只需多次燒錄程序就可實現(xiàn)迭代補償,通過對三個典型溫度點粗補償和全溫度段精補償,較便捷地實現(xiàn)了高精度零偏補償。經(jīng)過試驗驗證,設(shè)計的產(chǎn)品全溫零偏小于0.15 Hz,功耗為典型電路的1/5,具有較高的工程應(yīng)用價值和良好的市場前景。
中圖分類號:U666.12
文獻標(biāo)志碼:A
DOI: 10.16157/j.issn.0258-7998.223356
中文引用格式: 汪金華,游超,莊永河,等. 一種低功耗電流/頻率轉(zhuǎn)換電路零偏補償方法[J]. 電子技術(shù)應(yīng)用,2023,49(7):130-133.
英文引用格式: Wang Jinhua,You Chao,Zhuang Yonghe,et al. A zero offset compensation method for low power current/frequency conversion circuit[J]. Application of Electronic Technique,2023,49(7):130-133.
A zero offset compensation method for low power current/frequency conversion circuit
Wang Jinhua,You Chao,Zhuang Yonghe,Yang Yang,Li Honggao,Wu Xiangdong
(Anhui Province Key Laboratory of Micro System, The 43rd Research Institute of CETC, Hefei 230088, China)
Abstract: The current/frequency conversion circuit is mainly used to measure the output current of accelerometers in inertial navigation system, and at present the typical current frequency conversion circuit consumes so much power, which limits its application scope. Shunt circuit is usually used to design low power current/frequency circuit, however this method will bring large zero bias error, which affects the accuracy of circuit measurement. The reasons that affect the zero bias of low power current frequency conversion circuit are analyzed, and a method to realize zero offset compensation by single chip microcomputer is presented, it only needs to load the program several times to realize iterative compensation, through coarse compensation for three typical temperature points and fine compensation for the whole temperature range, and it is convenient to realize high-precision zero offset compensation. The experiments show the zero offset of the designed product at whole temperature is less than 0.15 Hz, and the power consumption is 1/5 of that of typical circuit, which has high engineering application value and good market prospect.
Key words : current/frequency conversion;low power;single chip microcomputer;zero offset compensation

0 引言

電流/頻率(I/F)轉(zhuǎn)換電路的用途是將模擬電流信號按線性比例關(guān)系轉(zhuǎn)換成數(shù)字頻率信號,目前典型的基于電荷平衡原理的電流/頻率轉(zhuǎn)換電路具有分辨力高、精度好、抗干擾力強等優(yōu)勢,應(yīng)用廣泛[1]。

典型方法通常是對輸入電流直接進行轉(zhuǎn)換,性能指標(biāo)已經(jīng)達到較高水平,但該種結(jié)構(gòu)存在產(chǎn)品功耗較高、發(fā)熱量大的問題,限制了其市場應(yīng)用。目前解決此問題的方法主要有采用開關(guān)切換分流和直接串聯(lián)電阻到地分流兩種放式,其中開關(guān)切換分流方式電路復(fù)雜,整體功耗下降較小,成本仍較高[2]。而利用直接串聯(lián)電阻到地的分流結(jié)構(gòu)較為簡單,但會產(chǎn)生較大零偏,而零偏是影響電路測量精度的主要因素,雖有一些硬件補償方法,但是補償精度低且難以實現(xiàn)多次迭代,補償效果很不理想[3]。

對此在分流電路基礎(chǔ)上,設(shè)計單片機補償電路及算法程序進行零偏補償,通過粗補償和精補償實現(xiàn)快速迭代補償設(shè)計,較便捷地彌補了電路零偏誤差,達到了兼顧產(chǎn)品功耗和精度的目的。另外分流結(jié)構(gòu)電路在降低功耗的同時,對元器件價格、體積、性能等級要求也有很大下降,從而降低了產(chǎn)品的體積和成本,提高了產(chǎn)品的性價比和市場應(yīng)用前景。




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作者信息:

汪金華,游超,莊永河,楊楊,李鴻高,吳向東

(中國電子科技集團公司第四十三研究所 微系統(tǒng)安徽省重點實驗室,安徽 合肥230088)


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