# Questions tagged [control-loop]

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### Operational amplifier using power supply current as output [closed]

I have come across a circuit (I am not allowed to share it) with an opamp that uses a special output. The opamp's output is loaded with a resistor and has no other connection. It is the current drawn ...
• 535
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### Buck loop transfer function

I saw two types of buck loop transfer function from two sheets, and the difference is the second type didn't consider H(s) from compensation network. Here is the first type, error-amp with ...
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### Differences in current loop transmitter

I'm studying loop powered transmitters (the 4-20mA thing), because I need to make one. I've found two different reference design which mostly use the same technique but with some slight difference. ...
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### Please help me clear up this confusion regarding gain margin and phase margin and unity feedback

I understand the physical significance of gain and phase margin. However, I would like some clarification regarding the mathematical aspects. Videos such as the following: https://www.youtube.com/...
199 views

### Grinding on PI/PID controller at specific PWM

I've modified a previous PI controller of a design team on that is working on high speed motor applications to include the D, which didn't solve this issue. The PID loop takes actual speed, and ...
51 views

### what is the open and closed loop function of this system?

i found this in the text book. i solved by: 1- found the closed loop function of just the part of B(p) and its "feedback", let's call it B'(p). 2- after that i did H(p) = A(p) / ( 1 + A(p) * ...
151 views

### Comparator as operational amplifier

Using an operational amplifier as a comparator was asked quite a lot times here, but how does it behave the way around? I've a really cheap one in my circuit with low hysteresis and a MOSFETt push/...
• 133
1 vote
95 views

### Is it possible to find the voltage gain of the constant gain block of this control system?

I'm looking at the following circuit and I don't know how to find the gain of the constant gain block. The only information I'm given are the Bode plots (magnitude and phase) of the two transfer ...
• 31
1k views

### How to prevent algebraic loop in the control loop simulation?

I have been developing a simulation of the field oriented control of the three phase induction motor. The simulation is developed in the Scilab/Xcos (v5.5.2) which is a free of charge Matlab/Simulink ...
• 935
1 vote
41 views

### Solving PLL Loop BW Transfer Function

𝑍(𝑠)= (1+𝑠.𝐶2.𝑅2)/(𝑠.(𝐴3.𝑠^3+𝐴2.𝑠^2+𝐴1.𝑠+𝐴0) C2 = 0.0000001F R2 = 1000 Ohm A0 = 0.000000106034 A1 = 1.27859848E-12 A2 = 4.5011166848E-18 A3 = 4.31278848E-24 G(𝑠)= (𝐾𝑝𝑑.𝐾𝑣𝑐𝑜.𝑍(𝑠...
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### Closed loop equation initial value

I am doing math for a closed loop equation. I know the transfer function for a closed loop system is: (Image copied from "Loop Gain and its Effect on Analog Control Systems" by Gabino ...
• 59
579 views

### Nyquist stability criterion for positive feedback

it is known that the stability of a system with negative feedback may be analized through the Nyquist stability criterion, which is based on observing the number of turns around the point (-1;0) in ...
• 3,290
343 views

### PFC controller - How does it work?

I would like to better understand how a PFC controller works, especially PFC which work in CCM mode. I found the following documentation from International Rectifier: https://www.infineon.com/dgdl/an-...
• 2,014
3k views

### Confusion regarding root locus. Open loop or close loop?

Which transfer function ,open loop or close loop do we use/need as a pre req to perform root locus analysis? I have also attached a snapshot of the relevant webpage of university of Michigan. I have ...
• 477
1 vote
787 views

### MOSFET as heating element for a RaspberryPi

I developed a PID autotuning algorithm that I want to test outside of a simulation environment. For this purpose, I got temperature sensors to send data to a RaspberryPi. Now I need something to ...
• 115
148 views

### Trouble understanding Loop Filter in a PLL

I'm currently trying to understand the function of a loop filter. But where I'm stuck is that I know the output of the charge pump is a series of current pulses whose width is proportional to the ...
846 views

### What does Dominant pole/Pole mean related to capacitors and filters or Electronics in general for intuitive understanding

I am trying to understand the feedback compensation techniques of DC-DC Buck converters. And I drift to more and more small questions which make me want to understand the basics of poles/zeroes/...
• 3,422
195 views

### Poles and Zeros of a Transfer Function

I am trying to understand the physical meaning of poles and zeros of a transfer function. Can someone help me how to understand the Figure 2b in the link below? What does the height of the cone ...
• 3,422
1k views

### 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 ...
• 3,422
710 views

I have a actuator capable of measuring motor current and position via an encoder on the output shaft. The motor is a brushed DC motor running through a gearbox. My questions is in regards to the use ...
1k views

459 views

### Where is the pole introduced by the RC circuit?

I've implemented a circuit under a suggestion which solves stability issues when driving a MOSFET with an high capacitance, using an OpAmp. Now, the circuit suggested is this one, in which is modeled ...
• 1,290
9k views

### How to achieve very accurate/fine rotation with motor

I am running an experiment where I need to rotate a lightweight dial (<5 grams, so very low torque requirement, and fairly slowly), but need to do very accurate, fine steps of 0.03 degrees. ...
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83 views

### Software control system. Which one is it?

I wrote a software which replaces a discrete closed loop PI control circuit and now I was wondering what kind of control system is this equivalent to? This code drives the PWM which regulates the R_DS,...
3k views

### How to improve current control loop in power supply?

I'm working on MCU programmable bench power supply. Its range is 0-50V and 0-3A programmed in 10mV and 10mA increments. It will be published as open hardware and source code that anyone can use it if ...
• 179
748 views

### Step response to feedback loop with disturbance

When using step response to a feedback loop with disturbance. Why do we analyze the step response of the disturbance D and the step response of the input R separately. Instead of considering them ...
1 vote
722 views

### loops with C18 Compiler on mplabide for 18f4550

I am facing trouble with glowing multiple LED simultaneously on a 18f4550 micro-controller under the same " while(1) ". I am new programming. [C18 compiler with Mplab ide.] I was able to alternate ...
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601 views

### Confusion in feedback for switchmode dc/dc converter

I have a slight confusion in how the feedback pin works. The "$V_{ref} \times (1 + R_1 / R_2)$" seems like a shortcut to me, and I have trouble understanding how to feed a voltage in to it, to say ...
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