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應(yīng)用于電源監(jiān)控芯片的高精度、低功耗RC振蕩器設(shè)計(jì)
2022年電子技術(shù)應(yīng)用第10期
尚林林,周 盼,趙 鵬
深圳市國(guó)微電子有限公司,廣東 深圳 518000
摘要: 基于0.35 μmBCD工藝,設(shè)計(jì)了一種應(yīng)用于電源監(jiān)控芯片的單比較器結(jié)構(gòu)的高精度、低功耗RC振蕩器。RC振蕩器電路包括基準(zhǔn)模塊和RC電路產(chǎn)生模塊。源于RC電路工作原理以及如何減少溫度、電源電壓的變化對(duì)振蕩器頻率的影響。引入新型電源電壓補(bǔ)償,減少了由電源電壓變化引起的比較器遲滯時(shí)間的變化,導(dǎo)致振蕩器頻率發(fā)生改變。采用MOS管穩(wěn)態(tài)導(dǎo)通電阻具有正溫度系數(shù)特性,補(bǔ)償多晶電阻負(fù)溫度系數(shù)特性的線性補(bǔ)償方式,抑制了振蕩頻率隨溫度的變化。同時(shí)設(shè)計(jì)了一種帶5位譯碼器高精度、低功耗數(shù)字修調(diào)電路,有效提高了MOS管導(dǎo)通電阻的精度,克服了傳統(tǒng)溫度補(bǔ)償電路補(bǔ)償電阻阻值不精確的問題。Spectre仿真結(jié)果顯示,電源電壓在2.5 V~5.5 V范圍變化,振蕩周期誤差范圍為-0.8%~+0.14%,溫度在-40 ℃~125 ℃范圍變化,振蕩周期誤差范圍為-0.3%~+0.79%。整個(gè)RC振蕩器電路最大工作電流為5.1 μA,其中RC電路產(chǎn)生模塊最大工作電流為0.9 μA。RC電路產(chǎn)生模塊結(jié)構(gòu)簡(jiǎn)單,降低了電路復(fù)雜性從而減少電路的實(shí)現(xiàn)成本,該電路結(jié)構(gòu)已成功應(yīng)用于高精度、低功耗電源監(jiān)控芯片中。
中圖分類號(hào): TM752
文獻(xiàn)標(biāo)識(shí)碼: A
DOI:10.16157/j.issn.0258-7998.222668
中文引用格式: 尚林林,周盼,趙鵬. 應(yīng)用于電源監(jiān)控芯片的高精度、低功耗RC振蕩器設(shè)計(jì)[J].電子技術(shù)應(yīng)用,2022,48(10):43-47,53.
英文引用格式: Shang Linlin,Zhou Pan,Zhao Peng. Low power consumption, high precision RC oscillator for power monitoring chip[J]. Application of Electronic Technique,2022,48(10):43-47,53.
Low power consumption, high precision RC oscillator for power monitoring chip
Shang Linlin,Zhou Pan,Zhao Peng
Shenzhen Guowei Electronics Co.,Ltd.,Shenzhen 518000,China
Abstract: High precision and low power RC oscillator is designed which is applied to power monitoring chip . The circuit is fabricated in a 0.35 μmBCD process . The RC oscillator includs reference module and RC circuit generation module. Based on the principle of RC oscillator and the intention of reducing the influence of temperature and power supply voltage changes on the oscillator frequency. In order to reduce oscillator period varies with the supply power, a new type of power supply voltage compensation is introduced to reduce the influence of the change of power supply voltage on the hysteresis time of the comparator. And to suppress the effect of temperature on oscillator frequency, the on-resistance and linear resistance of MOS tube are used for temperature compensation. To improve the accuracy of the on-resistance of the MOS tube,and overcome the problem of the traditional supplementing resistance inaccurate, a high precision and low power digital tuning circuit with 5 bit decoder is designed. The simulation results show that the input voltage range is 2.5 V ~ 5.5 V, the oscillation period error range is -0.8%~+0.14%, the temperature range is-40°C~125°C,and the oscillation period error range is -0.3%~+0.79%.The maximum quiescent current 5.1 μA, RC circuit generation module is 0.9 μA.This circuit is simple in structure, low in cost and easy to implement, applied to many power monitoring chips.
Key words : RC oscillator; temperature compensation; supply voltage compensation; digital tuning circuit

0 引言

    常見的DC-DC電源、電源監(jiān)控等電源芯片,一般會(huì)使用振蕩器電路產(chǎn)生時(shí)鐘信號(hào),用于延遲、監(jiān)控等。而完全集成的RC振蕩器具有較好的溫度變化性能,可以用來取代晶體振蕩器,以減少電源芯片的尺寸和成本[1-3]。RC振蕩器的頻率和功耗是其主要的性能指標(biāo)[4-5]。但是RC振蕩器的頻率易受到電源電壓、溫度的影響,傳統(tǒng)RC振蕩器結(jié)構(gòu)中的比較器遲滯時(shí)間也會(huì)給振蕩器頻率帶來誤差[6]。

    如何減少溫度、電源電壓對(duì)振蕩器周期的影響是設(shè)計(jì)高精度RC振蕩器的主要難點(diǎn)。當(dāng)前RC振蕩器電路溫度補(bǔ)償的諸多方案中,常見采用正負(fù)溫度系數(shù)線性電阻疊加,產(chǎn)生不受溫度影響的充電電流[7-8],具有結(jié)構(gòu)簡(jiǎn)單、容易實(shí)現(xiàn)等優(yōu)點(diǎn),但是也存在線性補(bǔ)償?shù)碾娮枳柚狄资軠囟?、電源電壓發(fā)生較大的變化,阻值精度不夠等缺陷。對(duì)于電源電壓補(bǔ)償的方案中,主要利用電源到地的分壓電阻產(chǎn)生與電源電壓成比例的翻轉(zhuǎn)電平[9],雖然這種結(jié)構(gòu)可以有效地消除電源電壓變化對(duì)振蕩器周期的影響,但也存在不足之處,很難產(chǎn)生與電源電壓相關(guān)而與溫度無關(guān)的充電電流。對(duì)于比較器的遲滯時(shí)間帶來的誤差,一般采用的是對(duì)稱結(jié)構(gòu)的雙比較器結(jié)構(gòu)[10],可以有效消除比較器遲滯時(shí)間帶來的誤差,但是也存在電容和比較器的失配造成的誤差[11],同時(shí)會(huì)增加電路的復(fù)雜程度,增加功耗和電路實(shí)現(xiàn)成本。




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作者信息:

尚林林,周 盼,趙 鵬

(深圳市國(guó)微電子有限公司,廣東 深圳 518000)




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