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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What is the purpose of including (or excluding) the output resistor in the feedback loop of an op-amp buffer?
I have often seen (and made) circuits like this. It is a simple inverting op-amp buffer, plus a small current-limiting output resistor to protect the the op-amp if the output is shorted.
simulate ...
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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 ...
- 2,452
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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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Why do we compensate PWM controllers?
I have been studying switch mode power supplies for a while. I have understood the working principle of several common topologies But there is a detail in the control circuit structures which I still ...
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Help Understanding a signal rectifier
I was reading an electronics book and came upon this circuit.
I am having a difficult time understanding why the voltage across D1 is 0.6V. I understand that that the reason is because the input ...
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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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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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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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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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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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Flyback power supply instability issue
I have created a switching power supply:
Input: 230 V AC
Output: 12 V DC, 1 A
Controller: UC3844
Topology: flyback
Switching frequency: ~ 100 kHz
Schematic:
When I start this power supply, output ...
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Why does overshooting occur when probe's adjustable capacitor is under-value
I can't wrap my head around how overshooting (the spike) happens when the 10X probe capacitor trimmer (Cp) is under-tuned (i.e. adjustable capacitor's value is not high enough). There are countless of ...
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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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Role of input capacitance for cascode-input op-amp
In the below schematic of a cascode-input op-amp, the input transistors M1 and M2 present no capacitive load to the input signals, because their gate-source and gate-drain voltages are stabilized. The ...
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Controller vs compensator?
Both these terms: controller(forexample PID controller) and compensator(Lead compensator) are often encountered in control systems,but what is difference between these two?
Brain douglas in this ...
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Output voltage not stable - What is compensation with respect to DC-DC (buck converter)?
EDITS:
Input voltage range: 24V to 48V.
Changing the load current from 0.38A to 1.018A increases the mean output voltage from 12.779V to 13.26V. The supply should be producing 12.5V.
I'm using this ...
user220456
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2
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Buck Converter Compensation and Transient Response
I am trying to compensate a buck converter. I've set up an averaged model of a buck converter in LTSpice.
Here is a picture of the simulation. The B3 voltage takes into account the gain from using a 5 ...
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4
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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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2
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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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How feedback loop is done in wide voltage range laboratory power supply? TL494 compensation
Hello i would like to ask how is compensation done on switching PSU with wide range variable output voltage (from zero to several hundres of volts). I have succesfuly (I guess) simulate my own design ...
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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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1
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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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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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Constant-gm bias circuit
I am doing a study on Improvements in biasing and compensation of CMOS opamp.
Do you guys know how to come up with the equation for RDS4C ?
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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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2
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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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TL494 compensation
I am trying to make a homebrew power supply. It works at the moment, but compensation is not done yet.
Can someone help me to calculate and select the right poles and zeros? VCM is at error op-amp 1, ...
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2
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Reason to use a current loop in addition to a voltage loop in linear regulators
I recently came across this figure detailing the compensation of the UC3833 in the App Note “A High Performance Linear Regulator For Low Dropout Applications” Available here and they show the use of ...
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Op-amp - Lead compensator design
I would be very happy if anyone can help me find answer regarding to questions below:
The lead compensator is added to the system to increase the phase margin.
1'st picture is related to the ...
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Why is it easier to make a boost converter stable by feeding back a very small amount of output?
The image below is about peak current mode control for a boost converter. Someone said that it's easier to make it stable by feedback a very small of output like 1/10 Vout (or R2 << R1). ...
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14-Volt 6-Amp Power Supply Stability
Design Requirements:
The purpose is a linear DC power supply for 12-volt aircraft, marine, and amateur radio equipment
power source 20 volts @ +/-10%. (output 85W = 6A*14.2V)
Rser on V1 = 0.4 or ...
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Why is this buffered rail splitter oscillating and how can I compensate it?
Inspired by the question Op amp Power supply splitter with totem pole I played with the buffered rail splitter in LTspice. I placed a current sink as load on the output to simulate the current ...
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Loop compensation of a Buck Converter
I have a buck converter. TPS54260
Vin = 7V-20V
Vout = 5V
Iload=600mA.
I realise that there is a similar question in this forum but I was not able to get clarity.
I want to understand what do you ...
user220456
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2
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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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Current control loop compensation network
I have an application that uses n-channel Mosfet as a high-side switch controlled by an IC driver. The point of the Mosfet is to manage the inrush current to the load. I understand that the resistor ...
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2
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Compensation capacitor(s) in instrumentation amplifier
I wonder whether the discrete 3-opamp instrumentation amplifier requires any compensation capacitors:
simulate this circuit – Schematic created using CircuitLab
Is it in general recommended to ...
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3
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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 (...
- 1,661
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771
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Implementing an Avalanche Photo Diode Circuit
I am working on a circuit that will make low light measurements in the visible range. The measurements will be of biological samples that are fluorescing. For this application an Avalanche Photo Diode ...
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1
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Buck-boost output drops when loaded
The LTC3566, a PMIC intended for battery and USB supplied applications, integrates a battery charger, a power path and a buck-boost converter. For my board, I copy-pasted the schematic found on the ...
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1
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Op amp GBW compensation when used in MFB filter
I've been reading through this app note by TI where its proposed that when using a MFB filter a compensation resistor can be added to overcome limitations of lower GBW op amps. I've been working ...
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Stability issue: Compensation changes using Bode plot in LTspice
I am encountering issues with a LT8390 design, particularly in higher load current conditions, which leads me to suspect a stability problem. The design parameters are as follows: vin 18-36 (28v ...
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Do lead and lag filters have the behavior of high and low pass filters even if the zero and pole used are complex?
Consider the compensation transfer function \$\frac{s+z}{s+p}\$ so that the inequalities \$0<z<p\$ and \$0<p<z\$ correspond to lead and lag compensation respectively.
At very low ...
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Offset problems with charge amplifier
I have a question about designing a charge amplifier.
I am currently using this simple setup for my application. As input, I can use several commercial piezo-based accelerometers. I need a pretty ...
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Three-wire load cell and HX711 weight compensation
In my project I use a 3-wire load cell (like this (3-wire 50kg), but mine were purchased from eBay) and an HX711 for weighing.
My wiring is like this (but I use an Arduino Mini Pro 3.3 V):
Apparently ...
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1
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Implementation of Adjustable Current Limiting Circuit
I have a circuit that can deliver 0-10V and 0-100mA to a load, and want to have an adjustable current limit that will limit the current delivered. To do this I have a current shunt that I monitor, and ...
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1
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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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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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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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1
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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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1
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Compensator design for control systems
Currently, I'm working on linear control course from Nise's book. In the root-locus design chapter, some methods were explained for lag and lead compensator design which uses root-locus properties. ...
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