本文關(guān)鍵詞：寬幅CMOS可編程增益放大器研究　出處：《西安電子科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 自動(dòng)增益控制AGC 可編程增益放大器PGA 可變?cè)鲆娣糯笃鱒GA 高線性 dB線性增益控制范圍

【摘要】：對(duì)于CCD圖像處理系統(tǒng),可變?cè)鲆娣糯笃?VGA)是CCD處理器中模擬前端(AFE)電路的一個(gè)重要組成模塊�；贑MOS工藝的VGA可以用來在不同環(huán)境下設(shè)置不同增益值,調(diào)節(jié)輸入信號(hào)動(dòng)態(tài)范圍并且穩(wěn)定輸出信號(hào)功率,提供一個(gè)恒定輸出擺幅信號(hào)給后級(jí)模數(shù)轉(zhuǎn)換(ADC)電路。VGA處于CCD系統(tǒng)的模擬前端電路,需要處理的CCD信號(hào)擺幅較大,寬幅高線性是本論文的一個(gè)重要的設(shè)計(jì)指標(biāo)。另外基于AGC系統(tǒng),要求VGA的增益控制特性是呈dB線性,所以寬范圍dB線性是本論文設(shè)計(jì)的另一重要指標(biāo)�；贑CD系統(tǒng)為應(yīng)用背景,本文首先提出了一款寬幅CMOS可編程增益放大器,可以處理輸入擺幅為0~2V的離散信號(hào)或連續(xù)信號(hào),并將其放大到滿擺幅為2V輸出信號(hào)供給后級(jí)ADC進(jìn)行處理,有效位數(shù)達(dá)到15.81位。該P(yáng)GA主要由四大部分組成:電壓鉗位電路、源極跟隨電路、R-2R電阻衰減網(wǎng)絡(luò)以及固定增益值放大器。其中設(shè)計(jì)難點(diǎn)主要在于固定增益放大器中高性能三級(jí)運(yùn)放的穩(wěn)定性設(shè)計(jì),并且引入了電流鏡補(bǔ)償和共源共柵補(bǔ)償兩種補(bǔ)償方法使得運(yùn)放工作穩(wěn)定。本設(shè)計(jì)PGA基于SMIC0.18μm 1P6M CMOS工藝,電源電壓3V下,實(shí)現(xiàn)了42dB增益變化范圍(-1.08~41.06dB),增益步長(zhǎng)為6dB,-3dB帶寬不隨增益變化,達(dá)到114.58MHz。對(duì)于AGC系統(tǒng)中VGA的增益控制呈dB線性,提出了一款寬范圍CMOS開環(huán)VGA。VGA主要有三大部分:指數(shù)函數(shù)控制電路、可變?cè)鲆骐娐芬约肮材７答?CMFB)電路。其中指數(shù)函數(shù)控制電路是利用新型指數(shù)近似方程式擬合構(gòu)造CMOS控制電路,明顯提升了dB線性范圍,增益可變電路則基于負(fù)載和跨導(dǎo)同時(shí)改變結(jié)構(gòu)實(shí)現(xiàn)。同樣基于SMIC 0.18μm 1P6M CMOS工藝,電源電壓3V下,VGA仿真結(jié)果為增益值-30dB~32dB連續(xù)變化,dB線性增益范圍達(dá)到62dB,且誤差在±3dB之內(nèi),VGA輸入1dB壓縮點(diǎn)IP1dB為-20.79~8.72dBm以及電路-3dB帶寬變化從269.6MHz(最大增益32dB處)到2.609GHz(最小增益-30dB處)。
[Abstract]:For the CCD image processing system, a variable gain amplifier (VGA) is a CCD analog front-end processor (AFE) is an important component of the module circuit. CMOS technology based on VGA can be used to set different gain values under different environmental conditions, adjusting the dynamic range of input signal and stable output signal power, providing a constant output voltage swing after the level signal to the analog-to-digital conversion (ADC) circuit.VGA in analog front-end circuit of CCD system, CCD signal processing swing is large, wide and high linearity is an important design index in this paper. In addition, based on the AGC system, VGA is a dB linear gain control characteristics, so a wide range of dB is linear another important index in this thesis. Based on the CCD system as the application background, this paper proposes a wide CMOS programmable gain amplifier, can handle input swing for 0~2V discrete or continuous signal, And amplify it to full swing for the output signal of the 2V supply after ADC treatment, effective number reached 15.81. The PGA is mainly composed of four parts: the voltage clamp circuit, source follower circuit, R-2R resistance attenuation network and fixed gain amplifier. The design difficulty lies in the stability design of three stage operational amplifier high performance fixed gain amplifier, and the introduction of the current mirror compensation and cascode compensation two compensation method makes the operational amplifier stability. The design of PGA SMIC0.18 m 1P6M CMOS process based on the voltage supply of 3V, the 42dB gain range (-1.08~41.06dB), the gain step is 6dB, -3dB bandwidth with the gain changes, to reach 114.58MHz. for AGC system in VGA is dB linear gain control, proposed a wide range of CMOS open loop VGA.VGA consist of three parts: the exponential control circuit, variable gain circuit and Common mode feedback circuit (CMFB). The exponential control circuit is to use the new exponential approximation equation to construct the CMOS control circuit, significantly enhance the dB linear range, a variable gain circuit load and transconductance based on structure changed at the same time. The same SMIC 0.18 m 1P6M CMOS process based on the voltage supply of 3V, the simulation results of VGA for gain the value of continuous changes of -30dB~32dB, dB linear gain range is up to 62dB, and the error was within 3dB, VGA input 1dB compression point of IP1dB for -20.79~8.72dBm and -3dB circuit bandwidth changes from 269.6MHz (maximum gain 32dB) to 2.609GHz (minimum gain -30dB).

【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN722

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相關(guān)期刊論文 前2條

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本文編號(hào)：1433347