Questions tagged [control-loop]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0
votes
1answer
57 views

Steady state error [on hold]

Consider a type 1, first order system, whose open loop transfer function is (K/sT) with unity feedback. To this system if a step input of magnitude A is given, the response will be an exponentially ...
0
votes
0answers
23 views

Li-ion charger (MAX1737) input current limiting

I have been protoyping a 3S1P Li-ion charger for myself and it turned out pretty well except for the fact that I cannot get input current limit to match the expected (calculated) value. In my case (...
2
votes
1answer
56 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 ...
3
votes
2answers
97 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/...
0
votes
2answers
166 views

Cascaded current control

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 ...
1
vote
2answers
456 views

Transfer function of phase change controlled with capacitance

We have an RLC series circuit with sinusoidal voltage source of frequency \$\omega\$. The normal transfer function of current to voltage is: $$ G(s) = \frac{I(s)}{V(s)} = \frac{1}{R+s L+ \frac{1}{s C}}...
0
votes
2answers
203 views

Loop bandwith and open-, closed- loop gain in ADIsimPLL

I'm want to use ADIsimPll to calculate the loop filter properties for a PLL I want to build. I read some things in the programs help topics which I find somehow strange. Maybe you guys can help me out ...
0
votes
1answer
65 views

Any transfer function has the same denominator 1+T

Sometime ago, I came across some theory saying that in a control loop any transfer functions such as ...
0
votes
2answers
121 views

What exactly am I messing up in this control loop?

I am creating a simple control loop for a safety door for a machine. When the door is opened, the machine turns off. When its closed, the machine can operate. The way I have it set up now is that we ...
-1
votes
1answer
114 views

feedback loop for a single stage offline flyback that is powering 2 independent LED strings

I have a design that is a offline, single stage flyback, powering two different LED strings. The output of this converter is about 50W and the output voltage can range from 20V-45V. I'm using ST ...
0
votes
2answers
476 views

How to find the closed loop transfer function of the LT1619 current mode controller

I am trying to figure out what would be the closed loop transfer function of the LT1619 controller. This is the first step I want to make in order to design the feedback loop. What I already know ...
1
vote
3answers
343 views

Interpreting the open loop gain of a linear power supply

This question is related to a question asked earlier regarding a linear power supply build. It turns out that the circuit is oscillating quite badly; an issue not uncommon in feedback circuits. I've ...
0
votes
1answer
456 views

How do I get a closed-loop PID controller from a transfer function?

I have the transfer function below: $$T_c(s) = \frac{s+k_i}{m_0s^3+s+k_i}$$ It is assumed that \$k_p=1\$ and \$k_d=0\$. I am given that \$x_l(t)=[x_l(t),y_l(t)]^T\$ is the trajectory and the ...
1
vote
2answers
453 views

Positive feedback with constant transfer functions

If I have a control loop with positive feedback, the closed loop transfer function expression is: $$\frac{Y(s)}{X(s)} = \frac{P(s)}{1-P(s)H(s)} $$ where \$P(s)\$ is the direct loop transfer function ...
7
votes
1answer
151 views

What is a Jaffe-Rechtin PLL?

Eberhardt Rechtin and Richard Jaffe (both involved in NASAs DSN) published this paper (paywalled) on PLL-design and -performance back in 1955. It is referenced quite often, so I wanted to understand ...
1
vote
0answers
65 views

Digital PLL reference noise rejection

I have a fully digital implementation of a PLL. The problem that I have is the white noise coming from the PFD (you can view it as input jitter). I would like to filter it a lot, but an implementation ...
1
vote
3answers
9k views

Why does the opamp output voltage saturate?

simulate this circuit – Schematic created using CircuitLab Vout = Vin (1 + R2/R1) According to this positive feedback topology - made an error here, it's Vout = Vin(-R2/R1) (edit) Now I ...
0
votes
1answer
669 views

DC-DC boost converter using multisim. Output voltage keeps changing with input voltage

Link to circuit schematic simulation The circuit is from the above link. There is some problem with the control loop. The output voltage doesnt stay constant within the input range of 12-24v for ...
1
vote
1answer
397 views

Loop Bandwidth of PLL

How is the loop bandwidth of a PLL calculated? Is it the area under the Transfer Function vs. Frequency plot?
5
votes
1answer
742 views

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 ...
2
votes
2answers
450 views

Root locus of discrete time system

I have a question about a probably easy task, but I can't find the right K. I have the loop with an adjustable gain element given: $$Q(z) = \frac{H(z)}{1+ K\cdot G(z)H(z)} $$ I have given: $$H(z) ...
2
votes
2answers
167 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 ...
9
votes
4answers
8k 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. ...
0
votes
1answer
80 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,...
6
votes
1answer
2k 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 ...
1
vote
1answer
637 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 ...
3
votes
2answers
446 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 ...
7
votes
4answers
6k views

Does this voltage regulator use “on-off” control, or is it a voltage follower?

In Electronics A2 (GCE), we are currently studying voltage regulators. An example voltage regulator circuit is provided using an op-amp and a power MOSFET. I would judge this to be a voltage ...