一种16位电流舵DAC的高精度前台校准方法

基于28 nm CMOS工艺,采用一种高精度的前台校准技术设计了一款16 bit电流舵数模转换器(Digitalto-analog converter,DAC)电路。该前台校准算法对16 bit数据对应的所有电流源进行校准,并且使用的电流源只有两种大小,降低校准难度的同时也提升了校准的精度。该校准电路引入了两种校准补充电流,分别用于温度和输出电流变化引起电流源失配的补偿,进一步减小了DAC电流源的失配,有效提高了DAC的整体性能。采用校准后,在-40~85℃温度范围内,微分非线性≤0.8 LSB,积分非线性≤2.0 LSB,200 MHz输出信号下无杂散动态范围≥75.3 dB。该校准方法提高了DAC的温度稳定性。

基于DAC阵列的光交叉芯片控制驱动系统

为标定光交叉芯片驱动电压,控制光交叉芯片实现光路由功能,提出并搭建了基于多通道DAC(Digital to Analog Converter)阵列的控制驱动电路系统。系统主要由控制系统模块、多路驱动电路模块及上位机控制模块构成。控制电路和驱动电路具有调校简单、可双极性输出、输出路数多、加电精确度较高的特点,解决了当前驱动电路工作繁琐、加电极性单一、加电路数少、精度差的问题。上位机控制模块除了可控制驱动电路施加控制电压外,还可接收来自数据采集装置采集到的光功率信号作为控制驱动系统的反馈信号。通过分析控制电压与光功率之间的关系,可得到最佳的光交叉芯片控制驱动电压。系统测试实验结果表明,该系统能提供高精确度的双极性驱动电压,有效地对光交叉芯片进行驱动。可在较短的时间内标定出光开关的控制电压,完全可以满足有源光交叉芯片控制中对驱动电压的需求。该系统在光交叉芯片控制方面具有一定的应用价值。

新型辊压机DAC弧形双曲线进料装置的特性分析

针对辊压机进料装置的运动轨迹对系统效能影响较大,本文设计了一种新型DAC双曲线进料装置,对其结构组成进行了分解。通过对进料口、侧挡板、调节插板和驱动装置等四个关键要素的研究,提出了沟谷聚落式进料口、同轴层叠式侧挡板、透空式斜插板及智能一体化执行器的设计方法,并将结构特性进行了分析。经过产品设计后应用的情况,结果表明该DAC弧形双曲线进料装置可以将联合粉磨系统产量由210 t/h提高到237 t/h,提升幅度为12.8%,电耗由34.2 kWh/t降至31.9 kWh/t,增产节能效果比较明显。

一种12位低功耗电阻串架构DAC

利用分段式电阻串结构,基于CMOS工艺设计了一款12位3.4 MHz低功耗数模转换器(DAC)芯片。结合建立速度和静态性能的设计指标,确定“5+7”式分段结构,在保证建立速度的条件下考虑到电阻的失配性,实现良好的微分非线性(DNL)和积分非线性(INL)特性。后仿真结果表明,在3.4 MHz速度下,常温下DNL为0.14 LSB,INL为1 LSB,在-40~125℃下,DNL为0.6 LSB,INL为2 LSB,并且表现出-84 dB的总谐波失真(THD),以及在3 V电压下378μW的极低功耗,版图面积缩小到1.09 mm×0.91 mm。

基于FPGA的R2R DAC设计与仿真

随着通信技术和数字信号处理技术的快速发展,对数模转换器(DAC)提出了更高的要求,尤其在转换速度和转换精度方面,为此,设计了一种高精度的数字DAC系统。该系统包括DAC模块、电源电路和模拟滤波模块。其中,DAC电路设计是基于R2R电阻网络的架构,使用分立元器件设计的一种16位高性能数模转换器。输入端采用的是I2S通信接口,将输入的串行数据转为并行数据,再传输至电阻网络,经过DAC完成数模转换。通过设计的模拟滤波器对输出的模拟信号进行滤波处理,可使整个系统满足高精度和高分辨率的要求。最后,使用FPGA测试和验证该系统,发现数据转换结果达到了预期目标。

基于ATE的高速DAC射频参数SFDR测试技术优化

利用集成电路自动测试设备(ATE)测试高速DAC射频参数时,由于ATE测试板PCB走线较长、损耗较大以及机台提供的信号抖动比实装大等原因,导致ATE上高速DAC射频参数测试指标低于实装测试值。为此,文中介绍DAC电路的工作原理和测试方法;其次为解决上述问题,对测试码的生成以及PCB的布局等进行一系列改进,并将改进前后的测试值与典型值进行对比。结果表明,改进措施成效显著,大大优化了高速DAC射频参数的测试指标,使得SFDR等高频DAC动态类参数指标接近或达到实装测试值。

基于DWA 算法的DAC 芯片译码电路设计

本文主要讲述了基于DWA算法的DAC芯片译码电路的设计过程,给出了具体的设计思路。在设计过程中,使用温度计码来降低数字码切换瞬间输出的模拟信号产生的噪声,使用DWA算法来避免将较大的工艺匹配误差带入到输出的模拟信号中,本设计可以用于解决由于工艺误差所导致的电流源失配的问题。本文以5位输入信号的DAC芯片开关控制信号生成电路为例,利用ModelSim和Quartus II软件对代码进行了仿真,验证了设计思路的实现效果,基本判断设计方案可行。

低分辨率ADCs/DACs和低质量RF链技术辅助的D2D协助去蜂窝大规模MIMO系统

为了有效地解决当前频谱资源稀缺的问题,同时满足未来对大规模的无线接入和高速率的急剧需求,本文提出了低分辨率模数转换(analog-to-digital converters, ADCs)/数模转换(digital-to-analog converters, ADCs)和低质量射频(radio frequency, RF)链技术辅助的终端直连(device-to-device, D2D)协助去蜂窝大规模多入多出(multiple-input multiple-output, MIMO)系统,通过D2D分担数据传输压力,低分辨率ADCs/DACs和低质量RF链技术可用于减少硬件开销,从而提升系统传输速率与能量效率。研究发现增加接入点(access points, APs) APs数量、AP天线数量和D2D用户(D2D user, DUE)天线数量可以有效地提升系统的总速率,当比特数等于16或质量因子等于1时,系统总速率和总能量效率达到最优。此外,增加DUEs密度可以极大地提升系统的性能。研究结果为未来去蜂窝大规模MIMO的实际部署提供了参考方案。

DAC重磅新品,芯动神州发布DAC2167LFP-250高速DAC芯片

株式会社村田制作所(以下简称“村田”)已开发出了能够以超高水平精度检测姿态角和自身位置的小型6轴惯性传感器“SCH16T-K01”,主要用于工业设备用途。目前已开始提供样品,量产计划于2024年3月开始。以该产品为首的下一代6轴产品SCH16T系列今后将逐步扩大产品阵容。随着工业设备的高功能化,配备的电子元件数量也在不断增加,因此,传感器封装需要实现小型化。此外,由于工业设备的自动化程度不断提高,精确获取动态姿态角(1)和自身位置的需求也在不断增加。传感器各轴(X轴、Y轴和Z轴)的正交性是更精确地估算动态姿态角的一个重要因素,迄今为止,为了确保正交性,用户必须通过其他设备外部校准。

DAC重磅新品,芯动神州发布DAC2167LFP-250高速DAC芯片

芯片设计公司芯动神州微电子最新推出了一款高速数模转换芯片DAC2167LFP-250。该款芯片为双通道DAC芯片,分辨率为16bit,最高采样率达250MSPS。该芯片具有低噪声、低杂散、低交调失真的特点,并允许输出超过奈奎斯特频率的信号。由于该芯片具有高速、高精度和功能灵活等特性,在多个领域具有广泛的应用。

基于低分辨率DAC的IRS辅助去蜂窝大规模MIMO系统联合预编码设计

本文研究了下行链路智能反射面(Intelligent Reflective Surface, IRS)辅助去蜂窝大规模MIMO(Cell-Free Massive Multiple-Input Multiple-Output)系统,其中每个接入点(Access Point, AP)都采用了低分辨率的数模转换器(Digital-to-Analog Converters,DAC)。本文将IRS应用于去蜂窝系统并在AP处配备低分辨率DAC,进一步降低了硬件成本和功耗。采用加性量化噪声模型对低分辨率DAC进行数学建模,进而建立了下行链路用户和速率的表达式。由于公式具有非凸性和高复杂性,本文提出了一个交替优化框架来解决此问题,从而提高用户和速率。特别地,我们通过分数规划解耦这个问题,并采用拉格朗日乘子法和半定规划(Semi-Definite Programming,SDP)方法求得预编码矩阵和相移矩阵的表达式。最后,仿真结果表明,与传统的去蜂窝网络相比,该方案下的网络容量可以显著提高。

Daclatasvir plus asunaprevir in treatment-na?ve patients with hepatitis C virus genotype 1b infection

AIM To assess daclatasvir plus asunaprevir(d UAL) in treatment-na?ve patients from China's Mainland, Russia and South Korea with hepatitis C virus(HCV) genotype 1 b infection. METHODS Patients were randomly assigned(3:1) to receive 24 wk of treatment with d UAL(daclatasvir 60 mg once daily and asunaprevir 100 mg twice daily) beginning on day 1 of the treatment period(immediate treatment arm) or following 12 wk of matching placebo(placebodeferred treatment arm). The primary endpoint was a comparison of sustained virologic response at posttreatment week 12(SVR12) compared with the historical SVR rate for peg-interferon plus ribavirin(70%) among patients in the immediate treatment arm. The first 12 wk of the study were blinded. Safety was assessed in d UAL-treated patients compared with placebo patients during the first 12 wk(doubleblind phase), and during 24 wk of d UAL in both arms combined.RESULTS In total, 207 patients were randomly assigned to immediate(n = 155) or placebo-deferred(n = 52) treatment. Most patients were Asian(86%), female(59%) and aged < 65 years(90%). Among them, 13% had cirrhosis, 32% had IL28 B non-CC genotypes and 53% had baseline HCV RNA levels of ≥ 6 million IU/m L. Among patients in the immediate treatment arm, SVR12 was achieved by 92%(95% confidence interval: 87.2-96.0), which was significantly higher than the historical comparator rate(70%). SVR12 was largely unaffected by cirrhosis(89%), age ≥ 65 years(92%), male sex(90%), baseline HCV RNA ≥ 6 million(89%) or IL28 B non-CC genotypes(96%), although SVR12 was higher among patients without(96%) than among those with(53%) baseline NS5 A resistanceassociated polymorphisms(at L31 or Y93 H). during the double-blind phase, aminotransferase elevations were more common among placebo recipients than among patients receiving d UAL. during 24 wk of d UAL therapy(combined arms), the most common adverse events(≥ 10%) were elevated alanine aminotransferase and upper respiratory tract infection; emergent grade 3-4 laboratory abnormalities were infrequently observed, and all grade 3-4 aminotransferase abnormalities(alanine aminotransferase, n = 9; aspartate transaminase, n = 6) reversed within 8-11 d. Two patients discontinued d UAL treatment; one due to aminotransferase elevations, nausea, and jaundice and the other due to a fatal adverse event unrelated to treatment. There were no treatment-related deaths.CONCLUSION d UAL was well-tolerated during this phase 3 study, and SVR12 with d UAL treatment(92%) exceeded thehistorical SVR rate for peg-interferon plus ribavirin of 70%.

Real-world efficacy of daclatasvir and asunaprevir with respect to resistance-associated substitutions

AIM To investigate daclatasvir(DCV) and asunaprevir(ASV) efficacy in hepatitis C(HCV) patients, with respect to resistance-associated substitutions(RASs).METHODS A total of 392 HCV-infected patients from multiple centers were included in this study. We evaluated their clinical courses and sustained virologic responses(SVR) according to pretreatment factors(gender, age, history of interferon-based regimens, platelet counts, level of viremia, pretreatment NA5A:L31, and Y93 substitutions). We also analyzed the pretreatment and post-treatment major RASs of NS3:D168, NS5A:L31 and Y93 substitutions using a direct-sequencing method in 17 patients who were unable to achieve SVR at 12 wk after treatment completion(SVR12).RESULTS The overall SVR12 rate was 88.3%. Thirty-one patients discontinued treatment before 24 wk because of adverse events, 23 of whom achieved SVR12. There were no significant differences in SVR12 rates with respect to gender, age, history of interferon-based regimens, and platelet counts. The SVR12 rate in patients with viral loads of ≥ 6.0 log IU/m L was significantly lower than those with viral loads of < 6.0 log IU/m L(P < 0.001). The SVR12 rate in patients with Y93 substitution-positive was significantly lower than those with Y93 substitution-negative(P < 0.001). The L31 substitution-positive group showed a lower SVR12 rate than the L31 substitution-negative group, but the difference was not statistically significant. Seventeen patients who did not achieve SVR12 and had available pretreatment and post-treatment sera had additional RASs in NS3:D168, NS5:L31, and Y93 substitution at treatment failure.CONCLUSION Combination of DCV and ASV is associated with a high SVR rate. Baseline RASs should be thoroughly assessed to avoid additional RASs after treatment failure.

Combination therapy with daclatasvir and asunaprevir for dialysis patients infected with hepatitis C virus

The standard antiviral therapy for dialysis patients infected with hepatitis C virus(HCV) is(pegylated) interferon monotherapy, but its efficacy is insufficient. Oral direct-acting antiviral agents(DAAs) have recently been developed for chronic hepatitis C patients. However, some DAAs have contraindications for chronic renal failure(CRF). Daclatasvir and asunaprevir are metabolized largely in the liver and are not contraindicated in CRF. Combination therapy with daclatasvir and asunaprevir was used for 4 dialysis patients infected with genotype 1b HCV. One patient had viral breakthrough, and the 3 others had sustained virological response 12. One patient was admitted for heart failure and percutaneous coronary intervention due to concomitant ischemic disease. Heart failure was unlikely to be caused by the combination therapy, as it was probably due to water overload. The patient continued to receive the combination therapy after the remission of the heart failure. The combination therapy was well tolerated in the other patients.

Efficacy and safety of sofosbuvir and daclatasvir in treatment of kidney transplantation recipients with hepatitis C virus infection

AIM To assess the efficacy and safety of sofosbuvir and daclatasvir regimens for kidney transplantation(KT) patients with hepatitis C virus(HCV) infection.METHODS This study enrolled a prospective cohort of consecutive Chinese KT patients with HCV infection. They were given sofosbuvir combined with daclatasvir, with or without ribavirin. They were monitored regularly during and after the treatment. RESULTS Six patients were recruited in our prospective study cohort. All patients were male and naive to directacting antiviral treatment. The treatment duration was 12 wk. Most patients(4/6) were infected with HCV genotype 1b. HCV RNA was undetectable at week 4 after treatment and at the end of treatment in all patients. Sustained virological response rate at 12 wk was 100%(6/6). Two patients had to accept a half dose of sofosbuvir due to serum creatinine elevation during treatment. Kidney function in the remaining patients was stable. No serious adverse events(AEs) were observed. No patient discontinued antiviral therapy due to side effects. CONCLUSION Sofosbuvir and daclatasvir for treatment of KT recipients with HCV infection are highly efficient and safe. Patients tolerated the medications well, and no serious AEs were observed. Larger prospective cohort studies are needed to validate these results.

Probable case of drug reaction with eosinophilia and systemic symptom syndrome due to combination therapy with daclatasvir and asunaprevir

A 66-year-old, interferon-ineligible, treatment-naive man who was diagnosed with chronic hepatitis C due to hepatitis C virus genotype 1b began combination therapy with daclatasvir and asunaprevir. On day 14 of treatment, hepatic reserve and renal function deterioration was observed, while his transaminase levels were normal. Both daclatasvir and asunaprevir were discontinued on day 18 of treatment, because the patient complained of dark urine and a rash on his trunk and four limbs. After discontinuing antiviral therapy, the abnormal laboratory finding and clinical manifestations gradually improved, without recurrence. Our case fulfilled the diagnostic criteria of probable drug reaction with eosinophilia and systemic symptom(DRESS) syndrome. Despite the 18-d treatment, sustained virological response 12 was achieved. Based on the clinical course, we concluded that there was a clear cause-and-effect relationship between the treatment and adverse events. To our knowledge, this patient represents the first case of probable DRESS syndrome that includes concomitant deterioration of hepatic reserve and renal function due to combination therapy with daclatasvir and asunaprevir, regardless of normalization of transaminase levels. Our case suggests that we should pay attention not only to the transaminase levels but also to allergic symptoms associated with organ involvement during combination therapy with daclatasvir and asunaprevir.

Daclatasvir联合asunaprevir治疗基因1b型慢性丙型肝炎1例报告

Daclatasvir和asunaprevir作为直接抗病毒药物来联合治疗基因1b型慢性丙型肝炎患者,可获得较高的持续病毒学应答率。目前国内尚无使用该方案治疗基因1b型患者的报道。本文报告1例基因1b型慢性丙型肝炎青年女性患者使用该方案治疗24周,获得持续病毒学应答,最后临床治愈;但出现一过性胆红素升高、轻度血红蛋白下降,波动于100~110 g/L。

Daclatasvir vs telaprevir plus peginterferon alfa/ribavirin for hepatitis C virus genotype 1

AIM: To evaluate daclatasvir vs telaprevir, each combined with peginterferon alfa-2a/ribavirin(peg IFN/RBV), in treatment-naive hepatitis C virus(HCV) genotype(GT) 1-infected patients.METHODS: In this phase 3, randomized, open-label, noninferiority study, 602 patients were randomly assigned(2:1) to daclatasvir vs telaprevir, stratified by IL28 B rs12979860 host genotype(CC vs non-CC), cirrhosis status(compensated cirrhosis vs no cirrhosis), and HCV GT1 subtype(GT1a vs GT1b). Patients were selected by study inclusion criteria from a total of 793 enrolled patients. Patients received daclatasvir 60 mg once daily or telaprevir 750 mg 3 times daily plus peg IFN/RBV. Daclatasvir recipients received 24 wk of daclatasvir plus peg IFN/RBV; those without an extended rapid virologic response(e RVR; undetectable HCV-RNA at weeks 4 and 12) received an additional 24 wk of peg IFN/RBV. Telaprevir-treated patients received 12 wk of telaprevir plus peg IFN/RBV followed by 12(with e RVR) or 36(no e RVR) wk of peg IFN/RBV. The primary objective was to compare for noninferiority of sustained virologic response rates at posttreatment week 12(SVR12) in GT1b-infected patients. Key secondary objectives were to demonstrate that the rates of anemia(hemoglobin < 10 g/d L) and rashrelated events, through week 12, were lower with daclatasvir + peg IFN/RBV than with telaprevir + peg IFN/RBV among GT1b-infected patients. Resistance testing was performed using population-based sequencing of the NS5 A region for all patients at baseline, and for patients with virologic failure or relapse and HCV-RNA ≥ 1000 IU/m L, to investigate any link between NS5 A polymorphisms associated with daclatasvir resistance and virologic outcome. RESULTS: Patient demographics and disease characteristics were generally balanced across treatment arms; however, there was a higher proportion of black/African Americans in the daclatasvir groups(6.0% and 8.2% in the GT1 b and GT1 a groups, respectively) than in the telaprevir groups(2.2% and 3.0%). Among GT1 binfected patients, daclatasvir plus peg IFN/RBV was noninferior to telaprevir plus peg IFN/RBV for SVR12 [85%(228/268) vs 81%(109/134); difference, 4.3%(95%CI:-3.3% to 11.9%)]. Anemia(hemoglobin < 10 g/d L) was significantly less frequent with daclatasvir than with telaprevir [difference,-29.1%(95%CI:-38.8% to-19.4%)]. Rash-related events were also less common with daclatasvir than with telaprevir, but the difference was not statistically significant. In GT1 ainfected patients, SVR12 was 64.9% with daclatasvir and 69.7% with telaprevir. Among both daclatasvir and telaprevir treatment groups, across GT1b- or GT1a-infected patients, lower response rates were observed in patients with IL28 B non-CC and cirrhosis- factors known to affect response to peg IFN/RBV. Consistent with these observations, a multivariate logistic regression analysis in GT1b-infected patients d e m o n s t ra t e d t h a t S V R 1 2 wa s a s s o c i a t e d w i t h IL28 B host genotype(CC vs non-CC, P = 0.011) and cirrhosis status(absent vs present, P = 0.031). NS5 A polymorphisms associated with daclatasvir resistance(at L28, R30, L31, or Y93) were observed in 17.3% of GT1b-infected patients at baseline; such variants did not appear to be absolute predictors of failure since 72.1% of these patients achieved SVR12 compared with 86.9% without these polymorphisms. Among GT1b-infected patients, treatment was completed by 85.4%(229/268) in the daclatasvir group, and by 85.1%(114/134) in the telaprevir group, and among GT1a-infected patients, by 67.2%(90/134) and 69.7%(46/66), respectively. Discontinuations(of all 3 agents) due to an AE were more frequent with telaprevir than with daclatasvir, whereas discontinuations due to lack of efficacy were more frequent with daclatasvir, due, in part, to differences in futility criteria. CONCLUSION: Daclatasvir plus peg IFN/RBV demonstrated noninferiority to telaprevir plus peg IFN/RBV for SVR12 and was well-tolerated in treatment-naive GT1 binfected patients, supporting the use of daclatasvir with other direct-acting antivirals.

Effects of dual sofosbuvir/daclatasvir therapy on, chronic hepatitis C infected, survivors of childhood malignancy

BACKGROUND Childhood cancer survivors are potentially at a higher risk of infection with hepatitis C virus (HCV).The effects of all-oral direct-acting antiviral therapy (DAA) on both the HCV infection as well as the state of cancer remission have not been well investigated in this population.AIM To test the effects of dual sofosbuvir/daclatasvir (SOF/DCV) therapy in the treatment of chronic HCV in survivors of hematologic malignancy in pediatric age group.METHODS We conducted a prospective,uncontrolled,open-label multicenter study.A total of 20 eligible,chronic HCV,genotype-4,infected children who had been in continuous complete remission from hematologic cancer (leukemia/lymphoma) for at least one year were included in the study.All patients were treated with combined SOF/DCV for 12 wk.Patients were monitored throughout the study till 12 wk after end of treatment for safety and efficacy outcomes including the sustained virologic response 12 (SVR12) rate,hematological indices,liver and kidney functions.RESULTS The intent-to-treat SVR12 rate was 20 of 20 (100%;95%CI: 84%-100%).All patients showed normalized liver enzymes from week-4.All hematological indices,liver and kidney functions were kept normal throughout the study.No fatalities or treatment-emergent serious or severe adverse events were reported throughout the study.CONCLUSION SOF/DCV combined therapy could be used safely and effectively in the treatment of chronic HCV genotype-4 infection in leukemia/lymphoma treated children.No relapses were detected during treatment and throughout the follow up period for either the original malignant disease or the HCV infection.

Interaction of immunosuppressants with HCV antivirals daclatasvir and asunaprevir: combined effects with mycophenolic acid

AIM To investigate the specific effects of immunosuppressants on the antiviral action of daclatasvir and asunaprevir.METHODS The antiviral activity of daclatasvir(DCV) and asunaprevir(ASV) combined with immunosuppressants was tested using two in vitro models for hepatitis C virus(HCV) infection.RESULTS Tacrolimus, rapamycin and cyclosporine did not negatively affect the antiviral action of DCV or ASV. Mycophenolic acid(MPA) showed additive antiviral effects combined with these direct acting antivirals(DAAs). MPA induces interferon-stimulated genes(ISGs) and is a potent GTP synthesis inhibitor. DCV or ASV did not induce ISGs expression nor affected ISG induction by MPA. Rather, the combined antiviral effect of MPA with DCV and ASV was partly mediated via inhibition of GTP synthesis.CONCLUSION Immunosuppressants do not negatively affect the antiviral activity of DAAs. MPA has additive effect on the antiviral action of DCV and ASV. This combined benefit needs to be confirmed in prospective clinical trials.