一种基于CMOS工艺的电荷泵锁相环芯片的设计

实现一个电源电压为5 V时捕捉范围为41~110 MHz,为3 V时捕捉范围为25~58 MHz的电荷泵锁相环(CPPLL)。给出了系统设计组成各部分的门级或者晶体管级原理图与分析设计,重点在VCO部分的参数设计以及环路滤波器的参数设计。采用0.5μm标准CMOS工艺,Cadence Spectre软件仿真证明,该系统具有良好的线性特性和捕捉时域特性。     

基于电荷泵锁相环的有源环路滤波器的设计

环路滤波器是锁相环中的一个关键模块,对宽带高压VCO进行调谐时,常采用有源滤波器。在论述了电荷泵锁相环基本原理的基础上,对有源环路滤波器的结构以及滤波器对锁相环性能的影响进行了分析,推导出有源环路滤波器参数的设计方法。根据课题设计了三阶有源环路滤波器,用ADS工具对锁相环系统性能进行仿真,仿真结果与理论相吻合。实验结果表明,所设计的滤波器满足了课题的要求,验证了本方法的正确性。     

锁相环中基于电流控制技术的电荷泵的设计

锁相环能够跟踪输入信号的相位和频率,并输出相位锁定、低抖动的其他频率信号,广泛应用于通信系统中。高性能的锁相环芯片的设计,是当今通信领域研究的一个重点。文中对锁相环电路中的电荷泵电路模块进行改进,设计出一种带有电流控制技术的差分型电荷泵,实现了低功耗、高充放电速度的目的,并很好抑制电荷共享效应。同时通过电流模滤波器电路的设计,减小了整体电路的噪声,降低了功耗。     

用于电荷泵锁相环的无源滤波器的设计

探讨了应用于无线通信领域的锁相环中的环路滤波器的设计方法。采用基于锁相环交流频域特性分析的方法，设计了电荷泵锁相环中的无源低通滤波器。文章讨论了基本无源滤波器的设计方法，着重介绍了三阶无源低通滤波器的设计过程。给出了采用这种方法设计的滤波器和电荷泵锁相环的仿真结果。     

电荷泵锁相环2阶无源环路滤波器的设计

根据电荷泵锁相环系统的传递函数,详细推导了2阶无源环路滤波器的设计参数,准确定义了自然频率、阻尼因子等相关设计参数,给出了相位裕度与阻尼因子的关系表。运用Matlab和Spectre进行联合仿真,结果验证了设计公式的准确性。     

基于ADF4117的电荷泵型锁相环设计

电荷泵型锁相环的设计主要集中在环路滤波器。为了解决各种环路滤波器对锁定时间要求较高,并在环路带宽较宽的应用中对参考频率附近杂散抑制不够,因而致使锁相环相位噪声及杂散恶化的问题。文中以ADF4117为基础,给出了一种带三阶无源环路滤波器的电荷泵型锁相环的设计方法。该方法能有效抑制杂散,使锁相环输出达到良好的相位噪声及杂散指标。     

基于电感电容振荡器的电荷泵锁相环的设计

设计并实现了一种采用电感电容振荡器的电荷泵锁相环,分析了锁相环中鉴频/鉴相器(PFD)、电荷泵(CP)、环路滤波器(LP)、电感电容压控振荡器(VCO)的电路结构和设计考虑。锁相环芯片采用0.13μm MS&RF CMOS工艺制造。测试结果表明,锁相环锁定的频率为5.6～6.9 GHz。在6.25 GHz时,参考杂散为-51.57 dBc;1 MHz频偏处相位噪声为-98.35 dBc/Hz;10 MHz频偏处相位噪声为-120.3 dBc/Hz;在1.2 V/3.3 V电源电压下,锁相环的功耗为51.6 mW。芯片总面积为1.334 mm2。     

一种用于时钟产生的低功耗电荷泵锁相环设计

设计了一种用于时钟产生的电荷泵锁相环(CPPLL),其压控振荡器(VCO)采用了新颖的带电流补偿的电流减法器结构。采用Charted2.5V、0.25μmCMOS工艺,整个芯片的面积为300μm×400μm,VCO输出频率范围为55MHz～322MHz。整个电路功耗低,VCO输出频率为240MHz时,功耗为6mW。Hspice仿真结果表明,VCO输出时钟为96MHz时,峰峰值抖动为320ps。     

一种可变带宽的电荷泵锁相环设计

介绍了电荷泵鉴相器原理,提出了在电荷泵鉴相器基础上既能加快锁定时间又能在锁定时减小抖动的自适应带宽锁相环。自适应带宽是根据锁相环路的状态自动增大或减小电荷泵电流。根据此思路对传统电荷泵电路稍加改进,并用ADS2006软件进行仿真,结果表明符合预期的效果。     

一种低功耗射频CMOS电荷泵锁相环的设计

CMOS电荷泵锁相环的应用越来越广泛,这也加强了人们该内容的研究与分析。过去,受各方面技术原因的限制,CMOS电荷泵锁相环在具体应用过程中的能量消耗较大,这对其应用造成了一定的不良影响,而近几年随着各项技术的逐渐成熟,人们加强了对低功耗射频CMOS电荷泵锁相环设计的研究,从而满足低功耗、快速锁定要求。目前,人们在该项内容的研究上已经取得了一定的成绩,但是与期望的标准还存在一定差距。文章研究了一种低功耗射频CMOS电荷泵锁相环的设计。     

A radiation-hardened-by-design technique for improving single-event transient tolerance of charge pumps in PLLs

A radiation-hardened-by-design (RHBD) technique for phase-locked loops (PLLs) has been developed for single-event transient (SET) mitigation. By presenting a novel SET-resistant complementary current limiter (CCL) and implementing it between the charge pump (CP) and the loop filter (LPF), the PLL's single-event suscepti-bility is significantly decreased in the presence of SETs in CPs, whereas it has little impact on the loop parameters in the absence of SETs in CPs. Transistor-level simulation results show that the CCL circuit can significantly reduce the voltage perturbation on the input of the voltage-controlled oscillator (VCO) by up to 93.1% and reduce the recovery time of the PLL by up to 79.0%. Moreover, the CCL circuit can also accelerate the PLL recovery procedure from loss of lock due to phase or frequency shift, as well as a single-event strike.     

Modeling and analysis of single-event transients in charge pumps

It has been shown that charge pumps (CPs) dominate single-event transient (SET) responses of phaselocked loops (PLLs). Using a pulse to represent a single event hit on CPs, the SET analysis model is established and the characteristics of SET generation and propagation in PLLs are revealed. An analysis of single event transients in PLLs demonstrates that the settling time of the voltage-controlled oscillators (VCOs) control voltage after a single event strike is strongly dependent on the peak control voltage deviation, the SET pulse width, and the settling time constant. And the peak control voltage disturbance decreases with the SET strength or the filter resistance. Furthermore, the analysis in the proposed PLL model is confirmed by simulation results using MATLAB and HSPICE,respectively.     

电荷泵中单粒子瞬变的建模与分析

It has been shown that charge pumps （CPs） dominate single-event transient （SET） responses of phase- locked loops （PLLs）. Using a pulse to represent a single event hit on CPs, the SET analysis model is established and the characteristics of SET generation and propagation in PLLs are revealed. An analysis of single event transients in PLLs demonstrates that the settling time of the voltage-controlled oscillators （VCOs） control voltage after a single event strike is strongly dependent on the peak control voltage deviation, the SET pulse width, and the settling time constant. And the peak control voltage disturbance decreases with the SET strength or the filter resistance. Further- more, the analysis in the proposed PLL model is confirmed by simulation results using MATLAB and HSPICE, respectively.     

Analysis and RHBD technique of single event transients in PLLs

Single-event transient susceptibility of phase-locked loops has been investigated. The charge pump is the most sensitive component of the PLL to SET, and it is hard to mitigate this effect at the transistor level. A test circuit was designed on a 65 nm process using a new system-level radiation-hardening-by-design technique. Heavy-ion testing was used to evaluate the radiation hardness. Analyses and discussion of the feasibility of this method are also presented.     

A fast AFC technique with self-calibration for fast-locking PLLs

A fast adaptive frequency calibration (AFC) technique with self-calibration for fast-locking phase-locked loops is presented with frequency-selecting switches. The proposed AFC directly calculates the proper switch states of the voltage-controlled oscillator (VCO). It requires only six clock cycles of the reference oscillator regardless of the number of VCO switches to reach the final switch state in the ideal case. The proposed method counts the number of VCO cycles per reference clock period for the minimum VCO frequency (MIN) and the maximum VCO frequency (MAX) during the first four-clock periods. For the following two-clock periods, the proper states of the VCO switches are set to the calculated value from MIN, MAX and the desired division ratio for a target frequency (EST). A frequency synthesiser with the proposed AFC was implemented on a 0.18?µm CMOS process. The AFC time decreased from 40 to 0.4?µs employing the proposed scheme such that the total lock time is 40?µs with the loop bandwidth of 40?kHz.     

锁相环频率综合器中高性能电荷泵设计

本文基于0.18μm CMOS工艺设计并实现了一种新的高性能电荷泵电路。采用宽输入范围的轨到轨运算放大器和自偏置共源共栅电流镜技术提高了电荷泵在宽输出电压范围内的电流匹配精度;同时,提出通过增加预充电电流源技术来提高电荷泵的初始充电电流,以缩短CPPLLs的建立时间。测试结果表明电荷泵在0.4～1.7V输出电压范围内失配电流小于0.4%,充电电流为100μA,预充电电流为70μA。在1.8V电源电压下,电荷泵电路锁定时的平均功耗为0.9mW。     

Design and noise analysis of a fully-differential charge pump for phase-locked loops

A fully-differential charge pump (FDCP) with perfect current matching and low output current noise is realized for phase-locked loops (PLLs). An easily stable common-mode feedback (CMFB) circuit which can handle high input voltage swing is proposed. Current mismatch and current noise contribution from the CMFB circuit is minimized. In order to optimize PLL phase noise, the output current noise of the FDCP is analyzed in detail and calculated with the sampling principle. The calculation result agrees well with the simulation. Based on the noise analysis, many methods to lower output current noise of the FDCP are discussed. The fully-differential charge pump is integrated into a 1-2 GHz frequency synthesizer and fabricated in an SMIC CMOS 0.18 μm process. The measured output reference spur is -64 dBc to -69 dBc. The in-band and out-band phase noise is -95 dBc/Hz at 3 kHz frequency offset and -123 dBc/Hz at 1 MHz frequency offset respectively.     

一种应用于频率综合器的全差分电荷泵的设计与噪声分析

A fully-differential charge pump（FDCP）with perfect current matching and low output current noise is realized for phase-locked loops（PLLs）.An easily stable common-mode feedback（CMFB）circuit which can handle high input voltage swing is proposed.Current mismatch and current noise contribution from the CMFB circuit is minimized.In order to optimize PLL phase noise,the output current noise of the FDCP is analyzed in detail and calculated with the sampling principle.The calculation result agrees well with the simulation.Based on the noise analysis,many methods to lower output current noise of the FDCP are discussed.The fully-differential charge pump is integrated into a 1–2 GHz frequency synthesizer and fabricated in an SMIC CMOS 0.18μm process.The measured output reference spur is–64 dBc to–69 dBc.The in-band and out-band phase noise is–95 dBc/Hz at 3 kHz frequency offset and–123 dBc/Hz at 1 MHz frequency offset respectively.     

Design of a high performance CMOS charge pump for phase-locked loop synthesizers

A new high performance charge pump circuit is designed and realized in 0.18μm CMOS process. A wide input ranged rail-to-rail operational amplifier and self-biasing cascode current mirror are used to enable the charge pump current to be well matched in a wide output voltage range.Furthermore,a method of adding a precharging current source is proposed to increase the initial charge current,which will speed up the settling time of CPPLLs.Test results show that the current mismatching can be less than 0.4%in the output voltage range of 0.4 to 1.7 V,with a charge pump current of 100μA and a precharging current of 70μA.The average power consumption of the charge pump in the locked condition is around 0.9 mW under a 1.8 V supply voltage.     

应用于高速串行接口的低噪声时钟发生器

设计了一种应用于28 Gbit/s高速串行接口的低噪声时钟发生器,包括全差分电荷泵、差分环路滤波器、差分压控振荡器。为了降低相位噪声,采用全差分结构来降低共模噪声和电流失配。为了进一步降低小数分频器引入的噪声,提出一种基于计数器的分频器。为了保证时钟发生器在各种工艺和温度偏差下均能自动锁定,设计了自适应调谐电容电路。采用65 nm CMOS工艺进行设计,芯片面积为0.36 mm²,整体功耗为36 mW。后仿真结果表明,该时钟发生器在14 GHz 锁定后的相位噪声是-113 dBc@1 MHz,压控振荡器的调谐范围是12.8~15.0 GHz,自动锁定电路能在全调谐范围内对电路进行自动调整和锁定。