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一種片外電容交叉充放電型振蕩電路設(shè)計
電子技術(shù)應(yīng)用 2023年3期
曹楊,,曹振吉,,曹靚,,趙桂林
(中國電子科技集團公司第五十八研究所,江蘇 無錫 214035)
摘要: CMOS環(huán)形振蕩器具有版圖面積小,、調(diào)諧范圍大,、電路簡單便于集成等優(yōu)點,廣泛應(yīng)用于各類電源系統(tǒng)及電子通信應(yīng)用中,。在常規(guī)的環(huán)形振蕩電路基礎(chǔ)上,,設(shè)計了獨立的充放電控制通路,實現(xiàn)了一種交叉充放電型環(huán)形振蕩電路,,并通過外接片外電容的方式,,得到更低頻率的振蕩周期?;?.18 μm工藝,,采用HSIM工具對電路進行功能仿真,經(jīng)過后端物理實現(xiàn)后,,版圖面積為172 μm×76 μm,,對電路進行提參后仿,結(jié)果表明:在3.3 V電壓及25 ℃條件下,,外接10 nF接地電容時,,電路獲得約1.2 ms的穩(wěn)定振蕩周期。在Vcc=2.7 V~5.5 V,、T=-55 ℃~125 ℃條件下,,時鐘周期的最大偏移為5.83%。該電路已成功應(yīng)用于某電源控制芯片中,。
中圖分類號:TN432 文獻(xiàn)標(biāo)志碼:A DOI: 10.16157/j.issn.0258-7998.223029
中文引用格式: 曹楊,,曹振吉,曹靚,,等. 一種片外電容交叉充放電型振蕩電路設(shè)計[J]. 電子技術(shù)應(yīng)用,,2023,49(3):77-81.
英文引用格式: Cao Yang,,Cao Zhenji,,Cao Liang,et al. An oscillator circuit with cross charge and discharge by off-chip capacitors[J]. Application of Electronic Technique,2023,,49(3):77-81.
An oscillator circuit with cross charge and discharge by off-chip capacitors
Cao Yang,,Cao Zhenji,Cao Liang,,Zhao Guilin
(The 58th Research Institute,, China Electronics Technology Group Corp., Wuxi 214035,, China)
Abstract: CMOS Ring Oscillator has many advantages such as small layout area, large frequency range and easy integration. It is widely used in the DC-DC buck converter and electronic communication systems. On the basis of the traditional ring oscillator circuit, an independent charge and discharge control path is designed to realize a cross charge and discharge ring oscillator circuit, and a lower frequency oscillation period is obtained by externally connecting an off-chip capacitor. Based on 0.18 μm process, the circuit has been simulated with HSIM tool. After the back-end physical implementation, the layout of the oscillation occupies an area of 172 μm×76 μm. Using tools to extract parasitic parameters from the layout and conduct post-simulation, the simulation results indicates that with externally connecting an off-chip capacitor, and the power supply voltage in 3.3 V and temperature in 25℃, the oscillator has a clock period of 1.2 ms. With the power supply voltage changes in 2.7 V~5.5 V and temperature changes in -55℃~125℃, the frequency deviation is 5.83%.The circuit has been successfully applied in a power management chip.
Key words : ring oscillator;charge and discharge of capacitor,;power management chip,;clock

0 引言

壓控振蕩器(Voltage Controlled Oscillator, VCO)作為時鐘產(chǎn)生電路,作為各類通信系統(tǒng)的核心組成部分,,被廣泛應(yīng)用于鎖相環(huán)(Phase Locked Loop, PLL),、高速時鐘、數(shù)模轉(zhuǎn)換器(Analog-to-Digital Converter, ADC)等多個領(lǐng)域,。當(dāng)前主流的壓控振蕩器分為LC振蕩器和環(huán)形振蕩器,。LC振蕩器通常由片上電容、電感和有源器件構(gòu)成,,品質(zhì)因素較高,,顯示出良好的相位噪聲特性,然而,,調(diào)諧范圍有限,、片上電感面積較大、與CMOS工藝兼容困難等問題也成為LC振蕩器的關(guān)鍵性缺陷,。相比之下,,環(huán)形振蕩器具有調(diào)諧范圍大、支持多相位輸出,、占用面積小,、電路簡單便于集成、成本低等優(yōu)點,,在CMOS工藝,、片上系統(tǒng)的快速發(fā)展下,成為一種很有吸引力的選擇并被廣泛應(yīng)用,。

環(huán)形振蕩器是由多個延遲單元串聯(lián)形成的閉合環(huán)路,,其噪聲抑制能力較差、受電源電壓影響較大,,導(dǎo)致產(chǎn)生的振蕩周期并不穩(wěn)定,,并不適用于設(shè)計高性能環(huán)形振蕩器。因此,本文提出一種具有獨立的充放電通路,、頻率可調(diào)的振蕩電路結(jié)構(gòu),,分別由兩個不同的電容交叉充放電形成穩(wěn)定的振蕩頻率,同時,,通過外接納法級電容,,突破集成片內(nèi)電容約皮法級的大小限制,得到低于1 MHz的較低頻率振蕩周期,。




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作者信息:

曹楊,,曹振吉,曹靚,,趙桂林

(中國電子科技集團公司第五十八研究所,,江蘇 無錫 214035)


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