Questions tagged [compensation]
For questions about designing electronics to account for undesirable characteristics or behaviors, such as frequency compensation in a feedback control system to avoid instability and/or improve gain and phase margin, reduce overshoot and ringing, improve bandwidth, etc. Consider using in conjunction with associated tags such as "feedback", "stability", "frequency-response", "nyquist-plot", "bode-plot", "operational-amplifier", etc., if appropriate.
157 questions
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Crystal compensation for temp and voltage
Introduction
I'm toying with the design for a fail-safe wall clock controlled by multiple 32.768kHz crystal oscillators. I'm currently reading about compensation.
Compensator from literature
From ...
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Emitter-coupled logic operation
For the operation of emitter-coupled logic and sedra smith book,
1) Compared to CMOS, why ECL is the faster logic family given that it requires so many transistors to propagate to output Y (T5 ...
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Static VAr Compensation
I have to design a 3 phase Reactive Power Compensation System with using only reactors, no capacitor is needed. Total capacity is 505kVAr, but 475kVAr will be done with contactors, rest (30kVAr) will ...
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Why is frequency compensation required here?
Circuit requirements:
DC voltage gain: 50dB
Unity gain bandwidth: 50MHz
Phase margin: 45 deg(60 deg is recommended).
The circuit is completely symmetric, so M1=M2, M3=M4, and M5=M6. Therefore the ...
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4-20mA current loop - transmit sensor reading
I am working on design loop current transmitter- to transmit reading value from thermocouple sensor using below design. I measured co-junction temperature using NTC instead of RTD.
During applying ...
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Hybrid Boost-Flyback Stability Issue
I tried to design a step up SMPS to create ~200-300V from a 24V input with an expected power of ~12W max. Since the project is for a hobby, I chose to attempt a hybrid boost-flyback converter to get ...
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Adjustable non-inverting Buck-Boost converter failing right after starting in boost-mode
I am designing an adjustable non-inverting buck-boost converter based on LM5176 chip. Adjusting is done by DAC via feedback network, more on that technique can be found here.
The input voltage is 32V ...
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-20 db/decade Gain Slope requirement for Stability?
I have been learning Analog Filter designing. I started with Loop Compensation in power supply. I came across a document. It ...
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DCDC converter load step and phase margin
When applying load step to a DCDC converter we can approximate the phase margin from the presence/absence of oscillation and the crossover frequency as well from the response time.
The question is: ...
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Dynamic Compensator in Control Loop
Sorry if this has been asked previously, but I couldn't find anything here or elsewhere on Google (but maybe I'm searching the wrong terms).
I'm trying to design a Type 2 compensator for a PWM chip I'...
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AD4610 - Is it possible to eleminate this single overshoot
I am trying to compensate input capacitance of the AD4610. It does not matter if it is actually over- or undershooting - there is always a spike:
I do not have this problem with the OPA4141 for ...
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Design of compensator type 2 for current mode control of boost converter
I have designed a boost converter with peak current mode control in PLECS. I have used the method of k factor approach to design the compensator.
The Bode plot transfer function of the power stage is ...
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Compensation for op-amp difference circuit
I have a difference amplifier built with an op-amp (specifically, I'm using the LT6237) with 10dB gain:
simulate this circuit – Schematic created using CircuitLab
As it is, without external ...
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Average current mode control compensation
This is the structure of average current mode control (source here).
Please look at signal \$V_{com}\$ at the positive input of PWM modulator.
For proper operation, in steady state the magnitude of ...
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Why is this Type I compensator phase not 270 degrees?
This is a Type I compensator with a pole at origin. The transfer function between \$V_{in}\$ and \$V_{out}\$ is as follows:
$$ \frac{V_{out}}{V_{in}}= -\frac{R_{2}}{R_{1}+R_{2}} \frac{1}{s (R_{1}|| ...
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Need for Temperature Compensation of Current Mirror
I am currently learning about current mirror configurations. I have made two of them so far. Both of them worked as desired but, when heated or cooled, the current through the right side (the side ...
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Overcoming cogging/ripple torque in gimbal motor
So I'm trying to figure out how to spin a camera on a brushless gimbal motor. I am feeding each of the terminals a sinusoidal pwm signal from a via 3 half bridges on the SN754410. Each of the pwm ...
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Type of capacitor for feedback / external compensation
Referring to the capacitor between the output and the inverting pin in an op-amp, in parallel with the feedback resistor --- should I use ceramic (NP0), or thin film?
We're talking bandwidth in the ...
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OP-AMP DC offset compensation
I do not know how to compensate the DC-offset caused by the Input bias current.
simulate this circuit – Schematic created using CircuitLab
How to compensate the input current bias DC offset? ...
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How to compensate gain and offset errors
I have an analog circuit which has an offset error as well as an gain error.
I can measure the analog output of the circuit and I am able to manipulate the gain of the circuit by means of a factor <...
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Op-Amp's Dominant-Pole Compensation
I'm reading "Op Amps for everyone" (http://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf) and I'm currently studying the chapter about the compensation of op.amps. but I'm missing a passage. At ...
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The Frequency Compensation of LT1683 in a DC-DC Converter
The fig. 10 of Jim Williams's article presents a 2A laser current source circuit using the LT1683. I am confused about the frequency compensation circuit of fig. 10 (pin 12 Vc of LT1683). The page 8 ...
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How the effect of the output inductor is minimized and filter offers only single pole by current mode control?
In this application note "Switching Power Supply Topology Voltage Mode vs. Current Mode", page 2, Current Mode Control section the author claimed as follows:
Since the Error Amplifier is now ...
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Intuitive to get pole and zero points for lead compensator
The circuit below is a lead compensator. I can easily know exact the pole and zero of the network by deriving the transfer function. However, I am wondering if there is an intuitive method to get the ...
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LM301 comparator and diodes on compensation
I'm trying to understand what's the purpose of the two diodes connected to the compensation pin (8), and what the output of the comparator is supposed to be.
Also, I'd like to remove the 5V supply and ...
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BJT vs OPAMP for RF signal amplification: BJT performs better, why?
I am working on developing RF wave generation from a DDS IC (AD9834-Analog device). The voltage we require as an RF signal is 6 times (3V peak to peak, sinusoidal, DDS output~=0.5V with supply to the ...
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Calculating values for compensation network (boost converter RC+C network)
I'm trying to build a boost converter with current mode PWM control, but I'm stuck at selecting capacitor and resistor values for compensation. I'm using a LT1619 as the controller IC:
simulate this ...
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Input Bias Compensation for a Comparator
I've been working on designing a discrete dual-slope ADC for school, and I've run into a problem. The schematic below shows my proposed input stage, an ideal integrator connected to a comparator. I've ...
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APD temperature variation
I know that the gain (M factor) of APD (Avalance Photo Diode) changes with temperature at a give reverse bias voltage, therefore, we need to a compensation either using a thermoelectric cooler or a ...
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Finding transfer function of a compensator circuit similar to a type 2 compensator topology
I know how to find transfer functions of op-amp circuits using equations derived from using Kirchhoff's current law (nodal analysis), and normally I don't have any problems solving them. However, I ...
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Op-Amp Input Bias Compensation for Multiple Feedback Filter
I'm adding an input bias current compensation network to the positive op-amp input of my band-pass multiple-feedback filter.
I'm setting the source impedance for the positive input pin equal to that ...
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Intuitive way to see pole/zero directly from schematic
The image below is the electrical configuration and the transfer function of a type II compensator using OTA.
By looking at the transfer function, we can easily see that the circuit has two poles (...
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Compensated Attenuator question
In the explanation, it explains that C2, C3, C4 are for frequency compensating the impedance of C1 which varies according to frequency.
Can someone explain how C2~C4 does it? and why the designer ...
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Approximation of a Non Ideal Differentiator
simulate this circuit – Schematic created using CircuitLab
The above circuit is a differentiator, the op amp is assumed to be a single pole op amp, that is \$ A=\frac{wt}{s}\$
The transfer ...
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Increase in compensation capacitor for op-amp
I am currently learning to design an op-amp, and understand that using compensation capacitors help to maintain stability of the op-amp.
Currently, my compensation capacitor has a value around 10 pf.
...
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Understanding in-loop compensation for capacitive-loaded OpAmp
I'm trying to understand the in-loop compensation for a simple amplifier loaded with a capacitive load, as seen in this article from Analog:
http://www.analog.com/library/analogdialogue/archives/38-...
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General process for compensating a complex system in the time domain
Say one has a system with feedback wrapping around some "complicated" system (more complicated than the traditional examples given):
simulate this circuit – Schematic created using CircuitLab
\...
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Control theory diagram for feedback circuit with compensation
An op-amp that drives a secondary gain stage might be given like this:
simulate this circuit – Schematic created using CircuitLab
Where it is important to note that FB1 is some impedence (...
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Wheatstone bridge offset
I have a Wheatstone bridge but I don't know the values of the resistances in it.
My excitation voltage is 5 V. But instead of having 2.5 V on each output lines I get one line at 3.3 V and the other ...
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Oscillations in Precision Voltage to Current Converter Design
I am trying to re-design the TI Precision Design - Low Level (5uA) V-to-I Converter. My design goals are:
Increase bandwidth from around 1kHz to 100kHz (ideally 1MHz in the future)
Increase output ...
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Stray Input Capacltance Compensatlon with constant-GBP OpAmp
In the book: Design with operational amplifiers and analog integrated circuits, section 8.2, it shows a circuit as below:
And give:
$$f_{z} = \frac{1}{2\pi(R_{1}||R_{2})(C_{n}+C_{f})},\:f_{p}=\frac{...
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Loop compensation design of buck converter
I am trying to design loop compensation with type-3 error amplifier for a buck converter. I'm a student and very inexperienced in this subject. Please bear with me.
Here is the general procedure ...
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Compensating Saturation Voltage of a transistor
simulate this circuit – Schematic created using CircuitLab
I am working on this circuit, which is a voltage controlled oscillator. I am using the transistor as a switch in this circuit. The ...
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Interpreting bode plot of type 3 compensation network for buck regulator
I'm struggling to design the type 3 compensation network for a simple buck PWM controller. The controller is a Richtek RT8110B. According to the datasheet, half of the type 3 network is in-built and ...
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Temperature compensation in transistor current cource
I am working with analysis of BJT current source. I didn't get the explanation of temperature compensation in NPN transistor with PNP and pull up resistor. How does it work actually?
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Op-amp with compensation has positive feedback with over-unity gain
I am looking at the following figure (Maxim APPLICATION NOTE 5129
Stabilize Your Transimpedance Amplifier):
(source: maximintegrated.com)
I just can't understand the following: in the region half-way ...
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Should I be concerned when loop gain rises back above 0dB on simulation?
Interim update
Okay, I just realized I screwed up on the simulation. When I added \$C_{bp}\$ I upset the "break" in the feedback loop necessary to get the loop gain. The left-side lead has to go to ...
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Feedback Gain Loss of Transimpedance Amplifier
I have designed a single-supply (3.3V) potentiostat that initiates electrochemical reactions, converts the generated electrochemical current into a voltage via a transimpedance amplifier (op-amp used ...
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Does my op amp need offset nulling?
I have built a photodiode circuit using AD712 (precision bifet) and the circuit is working as expected. I have added a programmable gain using a multiplexer which lets me choose a gain from 1 to 100 ...
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Lag compensator Design
I have a system with unity feedback using lag compensation to get \$10\%\$ overshoot and a settling time of \$1\;s\$. The continuous-time transfer function of the closed loop system is
$$g(s) =\frac{0....