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61 Threads found on edaboard.com: Overlapping Clock
from a single phase clock how to generate a two phase differential non-overlapping clock...
hi frens... can anyone plz tell me how to construct a pseudo two phase non overlapping clock generator using cmos transmission gates or using 2 input nor gates...
I need three phase non-overlapping clock paper or other material, not two phase. I can not find anything about three phase non-overlap clock, could you please share yours? Thank you!
Hello, guys I would like to know some materials about current spikes resulting from overlapping clock. Want to figure out the reason or analysis. Thanks.
I think the second one can work too. I am trying to make a two-phase non overlapping clock generator for my SC integrator. can u plz tell me why people use such a professional clock generator as this (im
Hello All, Im not so experienced with non-overlapping clock generators so have 2 probably quite basic questions on them: Going by the topology of two cross-coupled NOR gates with even numbers of inverters inserted in their feedback paths: - Are the inverters inserted to increase the non-overlapping durations? - Could you not just (...)
A popular clocking scheme is the two-phase clock, which consists of two signals called 1 and 2 that alternate being on and off .These values are generally nonoverlapping such that they are never both on at the same time (one must go off before the other goes on).
Hi, Can anyone provide me the reference to generate the non-overlapping clock generator (with earl phasing) and a divide by 8 circuit? thanks rampat
If this is to be implemented inside an IC and assuming the following (a) clock is of the order of MHz (b) This is a really good Foundry process then.......... Feed the clock into a non overlapping clock generator that generates two non overlapping phases. This can be done with two NOR gates and 3 or 5 or (...)
Good day EDA fellows... I'm having this 3 output non-overlapping clock generator circuit. I'm having concern regarding those 2 MOS (drain and source connected). What's their purpose? Thank you very much for spending time on this
Dear fellows, I am designing a CMOS Dickson charge pump. The charge pump works fine when using ideal non-overlapping clock sources (vdc from analogLib). The problem arises when using a clock oscillator (or even an ideal source) and apply it to a circuit to generate the 2 non-overlapping clocks. When (...)
I have a SC integrator implemented with complimentary switches. I use non-overlapping clocks. Does it matter if the complimentary clocks overlap. What i mean is, the complimentary switch runs on two clocks that are the inverse to eachother. ie. clock and then clockbar. So in an integrator (...)
Dear Wany, You will always find a glitch at every transition. But how major is it depends on where the code is changing. For example, in a 4 bit DAC, you will see a max glitch where there is a transition of code from 0111 to 1000. But you will also notice glitches during the 0011 to 0100 transition and so on. The reason for these glitches are :
As far as I can see, you have two options to solve the problem: 1) Digital solution: digitize these two inputs and perform the subtraction in digital domain, or 2) Use switched capacitor circuitry with two non-overlapping clock phase to get the V1-V2 function you required, if the sampled nature of signal processing is allowed. Other pure ana
Hi ezt, Thanks for your input! If we do not consider the overhead of two-phase non-overlapping clock and suppose the gain accuracy is not very critical, what is the criterion of choosing opamp structure between sc circuitry and conventional method ? regards, jordan76
I know we need to generate a non-overlapping clock for SC filter but what will happen once if the clock duty cycle is not 50%, for instance, 30%? Is the transfer function changed due to the non-fifity percent duty cycle?
1)Non-overlapping clock. How long we have to design the time gap between two phases. For example, the clock frequency is 1MHz, how about 3nS time gap? it's enough? 2)The common mode bias to switch Can we only use resistor divider to generate a voltage to bias the common mode node of switch? or, we need to make a low impedance to the (...)
i need schematic & W/l values , Trade off between speed & powerconsumption
well, i THINK that this is usually dependent on the clock frequency, also the kind of application this dff is used in. like if u are talking about multi-phase clock generator used in ADCs then the trise and tfall have to be lower than a certain limit not to violate the non-overlapping clock condition and also not to cut (...)
The sample and hold colck should high level no overlapping. and check the sample timing, CM switch should turn off first then sample switch turn off and then hold switch on. that can reduce the charge injection and clock feedthrough.
Hi Manikandan, Here are some of the guidelines that should be followed in High speed PCB routing Give a lot of consideration to component placement and orientation. • Avoid overlapping clock harmonics. Make a harmonic table for each clock. • clock signal loop area must be kept as small as possible. Get (...)
You can use Switched-capacitor type with non-overlapping clock for up to 13~4bit resolution.(two stage opamp or gain booster) For more resolution, you can use gate-bootstrapping technique. There are many helpful thing in S.Lee 's thesis.
I'm designing an integrated voltage doubler. The power is in the range of 20 uW. The supply voltage is approx. 2 times bigger than Vth. Since I use integrated capacitors, I have ~20% of parasitics associated with them. The other losses stem from parasitics of MOSFET switches. I use a non-overlapping clock. Four questions: :arrow: I get consider
Pls visit this link Some common Design Tips are here.... Guidelines for the design and layout of high-speed digital logic PCBs. • Give a lot of consideration to component placement and orientation. • Avoid overlapping clock harmonics. Make a harmonic table for each clock.
you can find answer in almost every textbook. normally you need to generate nonoverlapping logic first, by delaying the original clock and then pass it through NAND gate with the original signal. or more complicated one. then you may estimate the load of control logic, and scale the output buffer.
What is the real or optimum value of the non overlapping time of the two clock phases in a switched-capacitor CMFB circuit used for an integrator? What about the rising and falling time of the clock? Does it have any relation with the clock period? In my simulations the non overlapping time has a great (...)
i have to use of Non overlapping clock for S/H.all pieces of this project is real thus i must define real pulse source that have rise and fall time.i don't know that how specify these times,can we define percentage of pulse width for rise/fall time? (for example define rise time=0.1% Pulse width)
Hi All, I am designing the non-overlapping clock generation block now for sigma delta ADC. Since our sampling frequency is low (~1MHz) and our technology is fast(0.13um), it's kind of difficult to seperate the clock edges. One way to increase the delay is to use big capacitor on the signal path, but this increase area and current (...)
Hi I am trying to design a switched capacitor sampling system in virtuoso schematic editor. But I don't know how to: 1- Generate non-overlapping clocks. 2- How to model the switches? should I use like nfet or there are special switches? Thank you, M
The non-overlapping time is the delay through the chain: td(NOR)+2*td(INV). If you want to decrese it, remove those two inverters.
hi,all i'm designing a two phase non-overlapping clock generor for a pipelined ADC. in lots of papers,they combine a NAND2 following by a chain of cmos inverters for delay.but when i was simulating,i found that the delay of inverter chain is very small and it is not adequate. it is, however,still small when i add more inverters. anyone have good
Dear Friends, I am designing 10-bit SAR ADC. The blocks comparator, DAC has been completed. But I am fully unaware of, how to design the digital control circuit. Even I have tried with shift register, ring counter, D-FF , Non overlapping clock and gates. But couldn't succeeded. Even I am getting the problem in understanding the timing function f
Does anyone know how it works non-overlapping clock generator? The circuit takes a clock signal and generates a two-phase nonoverlapping clock. The amount of the separation is set by the delay trough the NAND gate and two inverters on the NAND output. My question is:Why these clock signal (...)
1- Regarding your digital, you need to design the clock generator circuit (non-overlapping clock), digital correction logic and the MDAC ( comparator + some gates + ...) 2- About literature, you can find theory in the following thesis (available in google): (a) Design for Reliability of Low-voltage, Switched-capacitor Circuits by (...)
Well, are you still having a trouble to understand the over-lapping and non-overlappign clock thing ??? What would happen if you feed 010101 pattern to that circuit with overlapping clock ? If you think it still works in this scenario, you probably don't fully understand synchronous circuit and need to go back to the textbook.
A simple clock generator would be a constant current feeding into a cap and using a comparator to look at cap slope to Vref ~ compare and reset cap and repeat. This comparator then just flips a D flip flop which then generates your 50K clock. Then you make an non overlapping nand latch to make your phi1 and phi2. hope this helps Jgk
I have 3 clocks in my design. The third pulse clock is generated based on first clock.What is the best to represent this third pulse clock. CLK1 and CLK2(duty cycle of 48%) are non overlapping phase clocks CLK3 is a pulse clock that is double the frequency of CLK1 but (...)
Hi fellas, I am designing a high speed track and hold in Switched-Source-Follower topology. But I don't know whether the clock signals should be non-overlapping or not. I have read a lot about the Switched-Capacitor type, and understand their clock signals should be non-overlapping. But what about SSF? I don't remember (...)
Hi, I want to make the layout of a non-overlapping clock generator. In that circuit i am using two delay elements each of which is a cascade of even number of slow inverters having small aspect ratios(20 inverters in series). Can i use common centroid or some another layout techniques while making layout of the delay elements? thanks in a
6800 clock signal is defined to be NON overlapping phase-1 and phase-2 however reading from datasheet, the delay time "td" is maximum 9100 nano second. this means phase-1 and phase-2 could be @ the same logic maximum 9100 ns. which I find it is contradictory to the NON overlapping requirement. could someone help me understand this (...)
Can you show me the simulation of the signals clock_POS and clock NEG You get the problem on clock edge ... therefore I think there might be something with your non-overlapping clock generator ....
You can see this material:Simulating Switched-Capacitor Filters with SpectreRF~I designed one 4th order switched capacitor biquad filter in UMC 180 nm technology using cadence software (version 5.10.41).This circuit is operating on a two phase non overlapping clock generator (i/p frequency = 1 kHz). To simulate this circui
Draw the circuit diagram of a one-bit Dynamic Shift Register, based on CMOS inverters and transmission gates, using a 2-phase, non-overlapping clock. Briefly explain the operation of the circuit Modify your design such that it has a parallel input and can store data when the clock is stopped. Briefly explain its operation For a (...)
Im designing a switched capacitor sigma delta A/D converter so i thought it would be appropriate to use a switched capacitor CMFB circuit in my fully diff. folded cascode opamp. I pretty much got the opamp circuit right except now i want to turn it into a subcircuit in SPICE. Since the CMFB circuit runs with non-overlapping clocks
Timing analysis of latch design is difficult. Over a large design, timing analysis becomes impossible. In the past, latch-based designs have been popular, especially for some processor designs. Multi-phase, non-overlapping clocks were used to clock the various pipeline stages. Latches were viewed as offering greater density and higher (...)
hello everybody, I got a question for the step response configuration, which I have not thought about clearly. My opamp is single stage fully differential fold-cascode OTA to drive capactive load. The CMFB is switch capacitor circuit. When I tried to test step response, I used unity gain feedback configuration (shown in figure (a)) and go
hi iam doing vlsi diploma in scl. iam getting lot of douts on fsm specially sequence detector like 100010110 for this type and also 1100xx10 with overlapping and nonoverlapping can any one explain how to draw state diagram for this type of problems
hi,everyone when i'm dealing with the simulation of a fully differential opamp in spectre,a puzzle baffle me.The schemetic and result is as follows. Common mode voltage selected by me equals 900mV,i use sc common mode feedback and telescope opamp for simplicity.i use this closed feedback(T&H) to achieve doubling the input voltage accurately.the
One of the situations where shielding is required is when say in M1, the bias lines are connected and you have a clock signal crossing the line in M3. Then the usual practice is to draw a M2 layer around the overlapping area and ground it. By this, the switching noise from the clocks are shorted to ground and the bias lines are 'shielded' (...)
Hi DFF not necessary. Use a simple latch (two inverters + two switches as given in every digital design book) . Remember using non overlapping clocks for different latches.