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.
34 questions with no upvoted or accepted answers
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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
2
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0
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606
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Trying to perform transient frequency response with LTspice or Microcap, TL494 compensation
I have tried to do Bode plot of my uncompensated plant by myself in LTspice 17.1, but the result looks strange to me. This topic is a follow-on to this one.. I have no clue why it comes with 290 ...
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AC analysis of SMPS shows instability. How to modify the analysis to reflect the transient stability?
Background
I have designed a switch-mode power stage with voltage-mode control that uses an LCLC filter in its output to obtain a very low ripple output voltage.
I have empirically arrived at a ...
- 23.4k
2
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Underlying reasoning behind lead and lag nomenclature of compensation
If \$0<z, \;p\$, the Laplace transform transfer function \$\frac{s+z}{s+p}\$ constitute two distinct types of compensators.
If we look at this schematic, \$0<z<p\$ (lead compensation) implies ...
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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 ...
- 1,661
2
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1
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fast analytical technique identifying poles/zeros using degree of freedom
I encounter some engineers who can quickly spot poles and zeros in the circuit by identifying "degree of freedom". For example, a typical technical discussion goes like : "a miller ...
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Buck-Boost fault mode on startup and gradual current decrease
I am using the TPS92692 in buck-boost mode with an analog signal to set Iadj and PWM. When I start the circuit, it consistently goes into fault mode and the fault pin is periodically set low. However, ...
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Thermal EMF on shunts
I tested the accuracy of a shunt resistor of 20 μΩ by applying short pulses of 100 A. At lower current levels near 0, I noticed the sensed current had a variation of ±300 mA. I did some research and ...
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Battery charger circuit confusion - drive and compensation
I'm building something that is going to have Li-Ion batteries so I'm trying to learn how a battery charger actually works. I've been looking over the datasheets for the BQ2000 and the BQ2954. I will ...
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0
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Boost PFC compensator design
I'm trying to design a type II compensator for my LT1249 boost PFC stage but I'm not sure on how to place the zero and poles frequencies using a typical error amplifier:
I have a working LTspice ...
- 388
1
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1
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DCDC booster oscillation because of small drops of input voltage
I'm stuck with this DCDC booster design that shows a bad oscillation output when a little voltage drop is present at the input.
I have already tried to change the inductance to 4.7uH (actually, the ...
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1
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1
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Type-2 compensator transient response
I'm looking to find the transient response to a step impulse of a type-2 compensator.
I already found the transfer function, but when it comes to finding the transient response by using the inverse ...
- 13
1
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1
answer
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Trouble with meeting design specifications of a second order system using Matlab
I am trying to solve the following question.
Consider the transfer function $$G(s) = \frac{1.247}{s^2+9.76s+23.8}$$ is in the forward path of a unity feedback control loop. Assume that it is ...
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1
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0
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Why are complex valued zero and pole not used in lead or lag compensation design?
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. It can be seen that ...
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0
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Phase Lag Compensator
I have a question on lag compensators in general.
Why do they increase both the rise time and the settling time? Is it due to the introduction of a slow pole?
Much thanks!
- 25
1
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0
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526
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Type 3 Compensation on Full Bridge DC-DC Converter with SG3525
I'm trying to build a 48V-400V full bridge dc-dc converter. I'm using sg3525 as pwm IC and trying to get isolated feedback from output and planing to do it with TL431.
When I study on it people are ...
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1
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0
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Using a suitable Compensator problem - Control Theory
Problem:
\$\,\,\,\$ A system is described by the open loop transfer function $$\frac{k(s+2)(s+7)}{(s+5)(s^2+2s+5)}$$
Design a suitable compensator in order to have \$w_n =\sqrt{10}\,rad/s\$ and \$\eta=...
- 205
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48
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Feedback 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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0
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140
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Cancelling optocoupler pole in an isolated voltage mode controlled smps
I am designing a 600W halfbridge converter with a voltage mode controller(TL494). I am using a type 3 compensator with TL431 as shown in the image below:
where:
The capacitor C2 constitutes the ...
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622
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Using UC3844 and TL431 to compensate a forward converter
I am designing a forward converter capable of providing 5A at 30V at the output. For the compensation part, I am thinking to use UC3844 in combination with TL431 to achieve peak current mode control.
...
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0
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118
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How to plot uncomensated loop gain in LTspice
I want to plot an uncompensated loop gain of a dcm flyback dc-dc converter. I know that I can derive the control to output transfer function and then plot the uncompensated loop gain but that just ...
- 180
0
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1
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107
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Feedback loop design (buck converter): Output capacitance- effective value or nominal value to be considered?
In this TI datasheet of TPS62180, it was mentioned that the LC filter combination should be selected from a set of predefined values. I understand this is usually the case for an internally ...
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28
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What is the term Flc in LM27402?
Hi while going through LM27402 IC, inorder to find compensate components of cc1,cc2 and so on, there is term called Flc, can anyone explain what it is?
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191
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IGBT Temperature Drift: How to Achive Stability?
I remember the BJT transistor circuits are designed to compensate for the fact that the parameters of the transistor change with the temperature. I could not find similar ready-to-use solutions for ...
- 191
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0
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250
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How to find the compensating gain required for the 2nd order control system to have 5% overshoot
I have a unity feedback control system with $$G(s) = \frac{1.247}{s^2+9.76s+23.8}$$ in the forward path. Now Imagine, I added a static gain K in the forwards path to make the %overshoot 5%. How can I ...
- 27
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0
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143
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Ratio of zero-pole in a lead compensator
I have a transfer function of a lead compensator designed for double integrator in the form
$$G(s)=\frac{2025}{s^2}\frac{s/39+1}{s/139+1}$$
The zero frequency is 39 rad/s and pole is 139 rad/s. I just ...
- 103
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0
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56
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Isolated Type 3 Compensator
I'm trying to build a full bridge dc-dc converter and planning to apply a type 3 compensator(voltage mode). When I check the isolated feedback type 3, I've read some comments indicate that it's hard ...
- 319
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0
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261
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Using frequency-compensated resistive divider as digital level-shifter
We have all seen the "frequency-compensated resistive divider" circuit in, for example, 10X oscilloscope probes:
simulate this circuit – Schematic created using CircuitLab
Has anyone tried ...
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1
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63
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Sensor Error Adjustment
I have been asked to improve the high end accuracy of a pressure sensor (Without modifying hardware). I have collected data from 30 samples and found a trend to the error. My question now is if it is ...
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0
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148
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How to determine these resistors in 2-pole 2-zero feedback loop compensation
I'm trying to build a 2-pole 2-zero feedback loop compensation for controlling a full bridge dc-dc converter. It's my first time doing this and I'm following the book power supply cookbook. Book is ...
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Slope compensation of MAX17498
I want to use MAX17498 in boost mode.
I have a problem setting the slope compensation. The slope (as I understand) is the gradient of the inductor's current ramp. The unit is [A/s] or [A/us]. However,...
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256
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opamp constant-gm bias circuit
I try to incorporate the constant-gm bias circuit (Figure 6 in Improvements_in_biasing_and_compensation_of_CMOS_opamp) into the PFC (positive feedback frequency compensation) opamp, but it resulted in ...
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207
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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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0
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371
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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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