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How to analyse this with nullor block?
The first is the schematics from NMOS4 with parasitic capacitance:I recently read an article on how to analyse the circuit with The Nullor and Some Applications.The equivalent nullor circuit. I am not...
View ArticleSine wave CMOS buffer from inverters with or without feedback
Is it possible to buffer a sine wave using inverters alone or with some kind of feedback?I've been browsing google for minimalistic (I'm in 3.3-12 V domain) sine wave buffers and this thought stuck in...
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Why does my MATLAB calculation/simulation differ greatly from my LTspice...
Here is my circuit in LTspice.The frequency AC is here:This is DC with .op command.--- MOSFET Transistors ---Name: m1Model: nmos-shId: 1.91e-04Vgs: 7.96e-01Vds: 9.03e-01Vbs: 0.00e+00Vth: 4.00e-01Vdsat:...
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Why will the offset of a source-follower which is connected to the output of...
I am currently reading chapter 12, "The Common-mode Feedback Circuit" in Analysis and Design of Analog Integrated Circuits by Gray and Hurst.Page 815, gives the following statement for improvement of...
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Unexpected oscillation when using op-amp positive terminal for feedback
I am simulating a simple constant-current source using LTSpice:In simulation and on the breadboard, this works as expected: U1 controls the M1 gate voltage, the voltage across R1 is a constant 5 V, and...
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How to compensate this circuit? [closed]
I'm using the circuit above to control the common-mode voltage of the 2 resistors. M16 is a current source. The OpAmp controls common-mode voltage by adjusting the resistance of M20.I need to adjust...
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Two port feedback analysis of shunt-shunt amplifier with unity feedback
To consider the effect of loading in a shunt-shunt amplifier that is being analyzed with two port analysis, we short the feedback network at the input/output to calculate loading at the amplifier...
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Deriving inverting op-amp configuration gain from feedback theory
I am trying to derive the gain of the inverting op-amp stage from feedback theory. I have done it for the non-inverting stage.I'm having some difficulty - how do I deal with the Vin in the feedback...
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Output impedance of a series shunt feedback amplifier
I am trying to find the output impedance of a series shunt feedback amplifier by converting it to a two port network.I know the input impedance: Ri=ri*(1+A.β)But I dont know how I should find the...
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Are there fully differential feedback amplifiers with series inputs?
There are several examples of the 4 feedback topologies in single-ended circuits.In the case of series inputs (i.e. series-shunt and series-series topologies), the input is connected directly to an...
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Ring oscillator frequency
According to Barkhausen's criteria, for oscillation the feedback should be made after phase difference of 2pi and gain has to be >=1.Now when I consider a ring oscillator if 2 inverters are...
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How to calculate feedback \$\beta\$ in two common-source stages feedback
The following is from the book Design of Analog CMOS Integrated Circuit, page 307.KCL at node F.$$ (V_{in} - V_F) g_{m1} + \frac{V_{out} - V_F} {R_F} = \frac{V_F} {R_S}$$$$\Rightarrow V_F =...
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Unable to model Transresistance amplifier with feedback correctly
I spent the whole day trying to figure why transresistance amplifier modelled with z-parameters does not match with nodal analysis results but I sill can't figure out. I desperate need help on this...I...
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SG3525 feedback identification
This is from a UPS which creates 350VDC from 12VDC, How does this arrangement work to control presumably the duty cycle of SG3525?Compensation (pin 9) and inverting input (pin 1) are connected directly...
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How can I avoid saturation in current source amplifier?
I'm designing a class d amplifier with current feedback as in figure belowwith the following features:Vbus=50V Iout programmable from 100mA to 1A rmsVout=35Vrms maxWhen the load overcomes the...
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Error amplifier selection
I'm simulating the "voltage error amplifier circuit" referenced from this articleIn the article, "Vcontrol" will drop to zero when "Vout" is larger than the reference voltage (1.215 [V] here)But i'm...
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Open the loop in voltage-current feedback
The following is a figure from 8.61 in Design of Analog CMOS Integrated Circuit, page 311:Here is the question: Calculate feedback \$\beta\$ of the following circuit:As we use the method of the book,...
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How to find feedback coefficient \$\beta\$ of this current-voltage feedback...
Here is the circuit from YouTube:In order to determine the feedback, we have to break the loop at the gate of M1.Assume A is \$\infty\$, so \$V_{GS}\$ of M1 is 0. As we know the \$V_S\$ of M1 is...
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How can we identify feedback network in this circuit?
The following is a figure from 8.47 in Design of Analog CMOS Integrated Circuit, page 301:The book tends to suggests that feedback networkHowever, I have a different opinion.
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How can I calculate loop gain when considering loading effect in...
This is the schematic.According to the figure from 8.5 in Design of Analog CMOS Integrated Circuit, page 277:Here we break the loop and add test voltage.It looks like impossible to find the...
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About stability in system with loop gain AB>1 in negative feedback
I have been reading about stability and feedback systems, and a very silly issue has appeared.We can describe a negative feedback system as what can be seen in the following picture:Image source:...
View ArticleHomemade EEG circuit common mode feedback
I am currently building a DIY EEG circuit using this guide. This guide is for when there are two inputs. How can I modify this so that I can also input two EMG signals too?It is common knowledge that...
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Calculating gain of ICF amplifier
I'm designing a circuit with an ICF (indirect current feedback) amplifier, and am trying to calculate the gain of the resultant circuit.Using the AD8237 I followed the example here when designing with...
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Stability analysis of cross-coupled amplifier in Cadence
I am trying to implement a cross coupled amplifier with OP-AMP feedback.I am not able to get it stable for a square wave however.The circuit looks as follows:The OP AMP is ideal from Cadence, all...
View ArticleFeedback compensation on a buck-boost led driver
I tried to calculate the compensation network for a TPS92692 in buck-boost topology and I can't find the same value for the typical buck-boost led driver (page 41 of datasheet).Section 9.2.2.2.12...
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Discrete-Time versus Continuous Time analysis of feedback system
Imagine a generic feedback system, where A is forward gain and F is feedback gain. I will now go over two cases where in i will analyse this system.1. Reference = 110, A=10, F=1In this case, it can be...
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What does this NMOS/PMOS connected to Vout do in this TIA (Trans-impedance...
I was trying to understand a TIA (Trans-impedance Amplifier) design by Behzad Razavi which I found here.But I don't get what the transistor marked below, which is connected to the Vout, does?I even...
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Analog Compensator Vs digital Compensator in Power electronics Converter
I was working on designing a feedback compensator for my buck converter. I decided to use the compensator circuit in the feedback and give its output to Arduino which gives the duty cycle as shown...
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How can I improve the feedback portion of my boost converter circuit?
I designed this boost converter to drive vacuum florescent displays, nixie tubes, and similar devices.It can drive a 10k Ohm load at 235V. I'm sure I can get away with larger loads as alot of the...
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Phase shift near saturation mitigation in input stage amplifier -- How does...
I'm trying to understand how this circuit works on the input stage to the 4192A Impedance Analyzer.Apologies for the quality... this is the best scan I could find. The design is furnished with the...
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