In this paper, a new circuit is proposed for charge pump for using in delay locked loop, and then simulated in ADS software in 0. 18 μ, m TSMC CMOSRF technology with 1. 8V in transistor level. By using DLL a precise synchronization can be performed through internal and external clocks. In this paper, based on introduced charge pump current mismatching can be solved and so the jitter will be decreased. Finally, 3. 7psec effective jitter in 920MHz for DLL is accrued. In this loop while UP and DN in each duty cycle are proportional to dead zone, not considerable current is flow on the output of CP. Because the UP and DN signals are in current source and by switching each one, probability of following the current to the output will be provided. However, prevents current transition to other switch if turned on.

Almost all logic systems have a main clock signal in order to provide a common timing reference for all of the components in the system. Supporting the highest bandwidth data rates among devices requires advanced clock management technology such as delay-locked loops (DLLs). The DLL circuitry allows for very precise synchronization of external and internal clocks. In this paper a low jitter and wide operation range Mixed-Mode Delay Locked Loop is presented. A multiperiodlocked technique is used to enhance the input frequency Range. Moreover, a new CP is proposed to suppress mismatch problem in single ended CPs. In this way jitter and static phase error specifications have been improved. The designed circuit has been simulated in ADS software, using TSMC 0.18 um CMOS process at 1.8V supply voltage. Simulation results show that the frequency range of the suggested DLL is from 170 to 1100 MHz. The rms jitter and power dissipation of the designed circuit at 1100 MHz are 3.3 psec and 4.554 mW, respectively.

Phase locked loops (PLL) are widely used in telecommunication systems. Frequency characteristics and settling time are the two most important features of PLLs. In phase lock loops, several nonlinear factors can be considered, one of which is the nonlinear behavior of the phase detector. In fact, load pump phase locking loops (CPPLL) are nonlinear systems due to the nonlinear behavior generated by the load pump. Although the applied current is fixed in an ideal load pump, this is not fixed in practice because of the non-ideal behavior of the transistors. In this paper, considering the channel length modulation (CLM) effect caused by the drain-source voltage of MOSFET transistor, a more accurate model is presented for the phase detector. By investigating the non-linear differential equation dominating the system and using the step-response approximation for the transient time analysis, new equations are obtained for the settling time and overshooting. In order to check the validity of the specified non-linear equations, the simulation was conducted in MATLAB Simulink. Moreover, in order to better assess the proposed method, the performance of a PLL subjected to the transistor’ s drain-source voltage has been simulated and the effect of the different loop parameters, such as the loop’ s resistor and current has been investigated. The final results showed the appropriate accordance of the analytical equations with the simulation results.

Due to the nonlinear behavior caused by the charge pump, charge pump phase-locked loops (CPPLLs) are nonlinear systems. In an ideal charge pump, the applied current is constant; however, in practice, it is not constant due to the transistor's non-ideal effects. In this paper, regarding the transistor's channel length modulation effect (CLM) on charge pump’s current, the non-linear differential equation of the system is obtained and shows that the phase lock loop is a nonlinear system with memory and Voltaire Series expansion can be used to analyze it. As a result, a method for estimating a jitter transfer with a second-order filter is proposed. System level simulation is used to validate the analytical results with particular emphasis on the jitter transfer characteristics. The effect of different loop parameters has also been studied. The experiments all show excellent conformance between analytical equations and simulation results.

In this paper, a new charge pump in CMOS technology is designed and implemented. By using the body bias to reduce the threshold voltage and controlling the voltage by using the voltage reference circuit, a DC to DC voltage booster circuit with high efficiency has been achieved to provide an input voltage of 320 millivolts and an output voltage of more than 1 volt. Simulations have been done so that the proposed voltage booster circuit can be analyzed in a state where the results are close to the fabrication results. The results indicate that compared to previous works, smaller capacitors have been used to reduce the area of the circuit as well as high output voltage by using the minimum number of transistors. The simulation results with 25 pF charge pump capacitor in each clock pulse frequency of 200 kHz show that the input voltage of 350 millivolts reaches 1.2 volts in less than 2 milliseconds. The proposed circuit can be suitable for radar and RFID applications with low power consumption.

Background and Objectives: Coronary artery bypass grafting (CABG) is usually performed through cardiopulmonary bypass (CPB). CPB, However, has been associated with several adverse effects. Recently, off-pump CABG technique is offered as an alternative to the standard on-pump CABG technique. The purpose of this study was to evaluate the safety of the off-pump technique by estimating serum enzymes e.g. Creatin Kinase (CK), CK-MB, Lactate dehydrogenase (LDH), Aspartate Transaminase (AST), measurement of cardiac troponin I and some postoperative complications.Materials and Methods: Ninety patients (75 males and 15 females) with angiographically defined CAD admitted to Shahid Madani Heart Hospital in Tabriz for coronary artery bypass grafting were selected. The off-pump technique was performed in 50 patients with mean age of 58‏. In 40 other patients with mean age of 56, the on-pump technique was applied. The blood samples were collected from the patients before, 6, 12 and 24 hours after the operation. The activities of CK, CK-MB, LDH, AST in all serum samples were measured by Cobas Mira autoanalyser, and cardiac troponin I concentration also was measured by Evernest model 3200 motion. Data regarding patient age, sex, familial history of cardiovascular diseases, number of vessels grafted, procedural time, transfusion of blood and blood pressure were recorded for the both groups of patients. Postoperative data regarding the incidence of complications including myocardial infarction, need for inotrop adminstration and death were also recorded.Results: In this study the activities of serum enzymes such as CK, CK-MB, LDH and AST after on-pump CABG technique were higher than those of off-pump technique (P< 0.05 in all cases). The levels of troponin I were significantly higher after on-pump CABG throughout the entire measurement period (P<0.01) compared with off-pump procedure. In both groups of patients no myocardial infarction was occurred during operation. In the off-pump technique procedural time was shorter and transfusion of blood was less than those of on-pump technique, but no difference was noticed among the other recorded data.Conclusion: Significant reduction in the release of enzymes and troponin I during operation by off-pump technique suggests that the technique causes less myocardial injury. On the basis of little changes in the activities of cardiac enzymes and troponin I in serum and presented data including a marked decrease in blood transfusion and shorter procedural time, it is concluded that off-pump CABG is a safe and effective technique in selected patients with appropriate coronary lesions.

Background- Neurocognitive dysfunction after cardiac surgery with cardiopulmonary bypass (CPB or “pump”) is a common complication, reported in up to 53% of patients. In many patients this morbidity is only mild and transient, but in 5% of cases, it is severe.Method-In this prospective study from June 2002 to July 2004,186 cases underwent coronary artery bypass graft surgery (CABG) using CPB or off-pump CABG (OPCAB), and they were evaluated for neurocognitive complications by mini-mental status examination.Results- The average age of the patients was 56±6.2 years, 62% were male and 38% were female. 121 operations were performed with CPB (on-pump) and 65 operations were done off-pump. Mini-mental status test was normal in 50% of off-pump CABGs and in 43% of on-pump CABGs, very mild disturbance was seen in 48% of off-pump CABGs and in 54% of on-pump CABGs (p value=0.192, NS), mild disturbance was seen in 2% of off-pump CABGs and in 3% of on-pump CABGs (p value 0.392, NS), and moderate or severe disturbance was not seen in either group.Conclusion- In our study, there was no significance difference in the frequency of postoperative neurocognitive complications between off-pump and on-pump CABG patients.