Questions tagged [switch-mode-power-supply]

A switch-mode power supply (SMPS) switches been fully-on and fully-off states quickly to maintain voltage regulation. They offer lower power dissipation and run cooler than linear regulators that continually dissipate power through a transistor.

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25 views

buck small signal modelling

I have a synchronous buck converter and my inductor current looks like this:- To add voltage-mode closed loop control, I need to do the small signal modelling of the converter. I am a bit confused if ...
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What could have been the fault on this power supply? [closed]

I have a cheap digital TV decoder that suddenly stopped working.It is a single device with its power supply on the same board as everything else. I knew it was still drawing current because of the ...
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Input impedance of a buck converter

I found the control to output transfer function and the line to output control transfer function and verify it by simulation. It fits :) (all this work is coming essentially from what I have learnt in ...
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Isolated discrete GaNFET driver implementation for flyback converter, 500kHz [closed]

I am about to embark on a project of making a discrete GaNFET driver. It should be isolated with a signal transformer. Do you have any suggestions for literature or designs? Below is my current ...
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84 views

Practical vs. theoretical buck converter

I am currently looking at open loop buck converters. I am running it with the following: Switching frequency (f) = 62500 Inductance (L) = 100e-6 Input voltage (Vi) = 5 Output current (Io) = 0.06 ...
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38 views

EMI Filter for Buck Converter

I'm trying to design an EMI filter for a buck converter and I'm following steps on: AN-2162 Here is the question: At page:6, for the Cf capacitor; two different capacitor values are calculated and ...
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43 views

MC34063 Output Voltage Sagging

I am working on a project where I have used MC-34063 boost supply on 3 pcb's and all the 3 places I have the same issue ie output voltage is steady on open circuit, but soon as ANY load is connected, ...
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34 views

Factors that effect what current a Synchronous buck enters the Discontinuous mode

Statement 1: The current at which the Buck SMPS moves into Discontinuous Conduction Mode is not fixed and changes due to different factors. From what I understood, a Buck SMPS enters discontinuous ...
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I'm working on a switch mode power supply project that only uses discrete components [closed]

I do not want to use any IC nor microcontroller, I've successfully made a boost converter within these parameters but my problem is a buck converter, like how do I output a stable voltage without a ...
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32 views

Block current flow out of powered USB hub when supply is off

I have a custom computer setup with a standard 5V SMPS module powering many attached devices: an Ethernet hub, USB hubs, Raspberry Pis. (To eliminate the need for 6+ wall-warts) I have a basic eBay ...
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40 views

Why offline regulator output diodes have a high voltage rating?

I am currently having a look at AC to DC offline buck regulators - regulators which convert AC mains voltage to smaller DC, without any isolation transformers. Two examples are AP3917 from Diodes Semi,...
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How do VAC ratings of flyback transformers translate to VDC ratings of flyback converters?

I am trying to design a 40-50W flyback converter but I am struggling to select an appropriately rated transformer. While most flyback transformers are rated in AC volts, plenty of flyback converters ...
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42 views

Can I use an isolated DC-DC module with breaking its isolation?

I'm in need of a DC-DC module on a project. The DC-DC module I have is here. This is an isolated module but in my situation its input and output is going to be on the same ground. Will it cause a ...
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SMPS isolation and earthling shock [duplicate]

I have a laptop, which comes with an SMPS charger. The laptop charger is a very common type. I know there are some earthing issues in my home. I need to fix that. But SMPS isolate mains from the ...
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44 views

How can I silence this noisy SMPS board?

I have a receiver and it's SMPS board is making a constant hissing sound which is noticable from a few steps away, so I'm sure it's not normal. The source is probably the ferrite transformer on it, ...
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I need help for design high voltage buck converter

I have a 500 Vdc from rectified 3 phase power and then I will make output to 220 V phase to phase 60Hz power. But 500 Vdc doesn't stabilized and Its need to step down to 220 Vdc stabilized. So, I use ...
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Impact of PFC output impedance on the regulation of a converter

I have determined the transfer function of my converter operating in closed loop configuration. Nevertheless I saw on the web that the transfer function is not the same if my converter follows a PFC. ...
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97 views

LM2576 simulation not working at datasheet frequency

I'm designing a buck converter with TI's LM2576. This is the functional block diagram of the IC, extracted from the the official datasheet Output node voltage will be a square wave, and inductor ...
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44 views

line regulation factor with 2 zener diodes

i want to calculate the line regulation factor of this circuit You can check below my work. is it right or not ? Correct me if i'm wrong Can we consider that Z1 has a similar function as the ...
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1answer
67 views

What could be the cause of high leakage inductance on my custom flyback transformer?

I've built a flyback transformer by hand for a circuit I am making and after shorting the secondary I have found my leakage inductance is very high. The primary inductance is around 2 mH, while the ...
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117 views

Excessive hysteresis in LM2577 step up converter

Update: The conclusion I'm coming to at this point is that I believe the IC is damaged. My reasoning is that the device simply is not responding to the control input in a meaningful way. It turns ...
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1answer
50 views

How to prevent Current Limiting Circuit failing short?

I am utilizing what I believe to be a fairly typical current limiting circuit at the input of a DC/DC converter. I am driving the converter from a battery so I can never exceed a certain current or I ...
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65 views

Alternatives to switching power supply

I designed an analog board using a ±12V switching power supply as the input source. Now I am wondering to desgin the 2nd version of it and enhance some aspects including eliminating a few tens mV ...
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60 views

Required voltage rating of PCB terminal blocks with high voltage power supply

I have designed a power supply with a 3kV output. I need connect it to external heat-sinked load. I have purchased some 15kV twisted pair cable to do this. I am unsure the best way to bring this ...
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39 views

How can I prevent my switching power supply from sudden voltage increases?

I'm currently using a 3kW AC/DC converter which gave 48VDC output(Switch mode power supply). The device is capable to deliver up to 62.5A current to the load. My application is a cyclic movement ...
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51 views

Flyback transformer temperature rise - reasonable value

I had build an flyback converter based on UC3845 and some high voltage mosfet - it works fine, however I've got one problem with it. (but i'm not sure if that actually is a problem) The core for the ...
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50 views

Can I use a laminated silicon steel transformer core as a low frequency boost converter core?

Since laminated silicon steel is used in low frequency transformers, can't I also use it as an inductor in a low frequency boost converter, at maybe 100Hz, theoretically shouldn't this work as well as ...
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Measuring high voltage, floating, negative voltage potential

I need to measure a floating high voltage in my DC/DC converter. See image below of the schematic which outlines in very basic terms the output of my converter. I am able to measure the -6kV with a ...
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77 views

Current limiting rectifier with capacitve reactance (isolated)

[UPDATE] I have answered my own question with links to experimental data and theory. Please expand on that answer if you can for the reference of future readers. Thanks for replies so far and ongoing....
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42 views

Does an iron nickel core work at high frequencies?

I have a toroidal Iron nickel core, which upon research I found was used in an amplifier transformer, I couldn't get much info in it but I want to know if I can use it in a boost or buck converter ...
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Flyback converter design using the LM5021

I'm trying to design a 24V output flyback converter using the LM5021 (with rectifier and filters included). This 24V will be used in a buck converter to decrease to 0-12V 3A with one transformer or 6A ...
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Can we go with a square wave disturbance for power supply impedance measurement?

How does a power supply impedance measurement instrument work? Create a sinusoidal load disturbance and measure the o/p voltage disturbance-> take the ratio-> Repeat for the entire freq range? ...
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Adding an adjustable constant current option to a LM5175 circuit

Disclaimer: I'm no electronics engineer and I have no experience in this kind of circuit! I do occasionally design simple analog circuits and PCBs, barely messing with opamps. Context: I'm about to ...
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122 views

What's The Purpose of One Additional Diode Here

I'm trying to build a AC/DC buck converter and I've found an application note from ST. Two diodes are connected series at input to rectify the AC, but one is enough to have a half wave rectification. ...
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64 views

Energy of flyback with multiple outputs

Where does the additional energy for flyback with multiple outputs come from? It appears that I can add as many secondary outputs as I want, but the primary voltage is Vin, and the primary current can ...
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SMPS feedback loop - stupid question about frequency

I am studying stuff related to switch mode power supply control loops. There is one thing I don't understand - it is the overall frequency concept and how should I simulate such things. For example, I ...
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PCB Review - LM5164

What you guys think about my LM5164 power board? Tried to copy the demo board version, 15-100Vin - 12Vout@1A.
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About generating positive and negative voltage from the same power supply

I have searched the internet on how to get positive and negative voltage from the same power supply and I found the attached circuit. When I measure between the points A and B, I get +5V. When I ...
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447 views

Understand average time current curve of a fuse

When I made my buck-boost converter (12v input) (1-20v 4A output max) I choose a 7A fast blow fuse at the input in base to the calc 80w/12V = 6.66A. Suppose my dc-dc converter drives 5A to output (...
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“shark teeth”-like PCB feature in high voltage section of modern HDTV

I found this tooth-like non-masked, solder-covered trace pattern on modern single board HDTV. It's in the 120VAC "HOT" section of the switch-mode PS. Looks like some sort of spark gap or ...
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Is HP 6623A Linear or Switching power supply?

I have an HP 6623A DC power supply and i wonder if its Linear or Switching power supply. I see in the manual it says linear, but i still wonder. Why i am asking: I am asking this, becouse after ...
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58 views

Hot-plugging power kills switch-mode converter

We have a small IoT device, that runs of an external 24v DC power supply brick (https://www.rapidonline.com/tt-electronics-t6367st-24vdc-60w-installation-smpsu-85-3795) This 24v supply connects to the ...
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Paralleling switch mode dc/dc converters for redundancy

I have a use case with 6 converters, 1 primary and 5 redundant. At the moment the system is configured to enable the next converter in an error daisy chain in case the supply voltage of the previous ...
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28 views

Can a MOV properly discharge a X-Capacitor?

I created an AC-DC SMPS with a EMI filter that consists of a X-Capacitor and Common-Mode Choke. IEC 62368-1 requires that capacitors be discharged below ES1 (60V) within 2s of being disconnected. As ...
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74 views

Small signal Forward converter

I am back again on this subject. I found the control to output transfer function (Iout/Vc) of my forward converter (current mode) which is particular as it is without output capacitor. Actually it is ...
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1answer
52 views

Determining capacitor value in a flyback converter

I have a dead audio mixer power supply (Soundcraft MTK 22) which I am trying to bring back to life and learn more about flyback converters in the process. This particular supply runs on 230VAC and ...
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46 views

What is the control Input of the small signal current mode PWM switch

I am trying to simulate the open loop transfer function of my system. My system is really classic. A converter (the plant transfer function), a sensor and a corrector which is a simple Integrator (1/(...
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31 views

Calculating RC snubber network current?

I'm trying to pick the components to use with this DC/DC Buck-Boost Converter. At page 13, the datasheet says, that for input voltages higher than 4.5 V I need to add an extra 2Ω/1nF RC snubber ...
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49 views

LM3478/LM5155 configuration on a wide input and output voltage range

In my last question I mentioned the case of obtaining different output voltages from a single switching regulator. I ended up running a successful simulation of such setup in LTSpice using MC34063 and ...
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Can you help identify the controller of smps

Found on smps it is probebly the controller - but couldnt find it on google Looks like it is writen 9202 834p4

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