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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21 views

Duty cycle generator (PWM Modulator)

Below is a circuit used to control duty cycle in SMPS, and I have some question about this design: Why the designer has connected the output of the error amplifier (Type 3 in this circuit) to the ...
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72 views

Buck-Boost Converter Modeling

I wanted to perform AC analysis for a buck boost converter using SIMetrix/SIMPLIS for simulation, using this simulator the designer does not need to the average model to get the frequency response of ...
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50 views

Where do we place a Pi filter?

I have used pi filters in the past with the USB powers and it worked great. This time I need the pi filters to smooth out the 24V supply from a regular SMPS power adapter. There is a load switch/fuse ...
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17 views

Designing high bandwidth current sensors for inductor current sensing

I am designing a high-frequency current sensor, suitable for sensing +/- 20 Amps at frequencies of 200kHz. This is being used in average current mode control application in an isolated forward ...
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44 views

Turn off MOSFET with diode - PWM controller Maximal output current

Here is my circuit (and I know that this circuit does not cause any problems at least for the moment): For turning on, the maximal current from the pin "OUT" is limited by the resistance ...
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40 views

Bulk Capacitor for Full Wave Rectification

By using notes from C.Basso Bulk Capacitor Calculation, I managed to plot the ripple curve for bulk capacitors for offline converters. This bulk capacitor location: Assume that my system is AC/DC ...
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36 views

Type 3 compensator design

I'm about to simulate a voltage mode buck-boost converter. To stabilize this converter, it is well known that we should use a type 3 compensator. The configuration of that compensator is given below ...
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22 views

Leading edge Vs Trailing edge PWM Modulator in SMPS

How does the leading or trailing edge affects voltage mode PWM modulators in SMPS and how to be aware of that? If we take the following modeling equation of voltage mode buck-boost converter: Which ...
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2k views

What is the purpose of this copper plate inside the SMPS transformer?

I took apart a laptop PSU, and inside the transformer there is a small copper plate electrically connected to a pin of one of the secondary windings which is grounded on the PCB: The plate is about ...
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39 views

Help needed in selecting the power architecture for my project

I had some trouble in finalizing the power architecture for my upcoming project. In a brief summary about the project, I am using a GPS device to acquire location of the vehicle and control two ...
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27 views

DCDC power supply replacement [closed]

I'm using MP2359 for my hardware projects for a while now. It has a lot of advantages, that's why I kept it for my designs: Layout design is matured, provides power for 5+ years now in multiple ...
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36 views

Li-ion battery charging circuit [duplicate]

Please I have some couple of 3.6v 3Ah cylindrical li-ion battery, but since I bought them, charging it became a huge problem. I first connected a single one to a 2A infinix phone charger (made in ...
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53 views

Simple self oscillating flyback converter [duplicate]

Please am studying about switching power supplies, starting from the simple ones. I've just concluded on joule thief and blocking oscillator, now am progressing to Self oscillating flyback converter(...
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41 views

Unstable behavior of Dc-Dc converter

I am currently working on a high voltage boost converter based on Dos4Evers 555 timer based one https://www.dos4ever.com/flyback/flyback.html (12v to 140-220V). I am running into an issue with the ...
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Forward converter - How to measure the equivalent leakage inductane of this model?

Here is the schematic that I found in an old AN from UNITRODE. https://www.smps.us/slup199.pdf Here is the equivalent schematic showing the magnetizing inductance and the leakage inductances: This ...
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59 views

High Voltage Half Bridge Drive

I am working on a project to produce high voltage output. Since I supply this circuit directly from mains I have some problems. Here is my representative circuit: I am controlling transistors from a ...
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77 views

How to make multi type voltage input? 24AC/DC to 24DC?

Task: Input voltage: 24V AC or DC (Client disides what to input into divice) output voltage 24V dc output current 1.25A. Buck-boost converter is a simple and expensive solution. I need some how to ...
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40 views

Design of a boost converter with large variation in output current and low output ripple

I'm working on the design of a 24V to 30V boost converter that needs to have an output ripple of less than 100 mV with an output current between 0 and 2 A. The output is used to power a controller for ...
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105 views

Multiple output Flyback - Stacked transformer - Cross regulation - TL431

Suppose I have the following output stage of a flyback: simulate this circuit – Schematic created using CircuitLab The schematic is a bit simplified but the idea is here. Do not pay attetion to ...
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44 views

Synchronous boost light load operation and general SMPS terms

What are the differences between the skip cycle, pulse skipping, diode emulation, and forced PWM at general DC DC converter light load operations? How do they work and when do I want to use them? Page ...
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1answer
52 views

Capacitor ESR Calculation

I'm trying to perform esr calculations of this capacitor(1uF): https://alconelectronics.com/wp-content/uploads/2020/06/KP-6-JUNE-2019.pdf to do that I need to know dissipation factor and at the bottom ...
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29 views

Can I replace p6ke110a with 1N4148 in my smps circuit

I am building an smps circuit using TNY280. I would like to know if I can use 1N4148 in place of p6ke110a to protect TNY280 from flyback voltage from transformer as they both have almost same specs
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Design (Block diagram/topology) of high-current (I>100 A) power supply

I recently watched this video about the design of a high voltage (300 V) commercial power supply. I reckon that the block diagram is essentially a bridge rectifier followed by a DC/DC convertor like ...
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69 views

Why SMPS call for multiple input capacitors

Implementing a LM2677 SMPS, the reference recommends 4 identical 10uF input caps for my design. I understand some of the reasons you may want to use multiple capacitors instead of a single one, and ...
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58 views

Type 3 compensator design for Buck-Boost converter

I'm practicing a design of a type 3 compensator for a voltage mode buck-boost converter, so I went through the book entitled "Switch mode power supplies Spice simulation and practical design"...
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45 views

High voltage, high current variable

I managed to make variable voltage and current for dummy load using IGBT with PWM control from Arduino, I plan to use the output as a variable power supply. The output from IGBT is a square wave so I ...
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34 views

Creating A High Voltage Power Supply

I am currently building my own high voltage power supply running off of a 10v input and a 360v output. The circuit will use a 555 timer switching at a frequency f that will drive a MOSFET to power a ...
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105 views

SMPS Transformer Area of Product

I've calculated the area of product needed for transformer, it's 71cm^4, but in core datasheets there is not value with cm^4 unit for example: https://www.tdk-electronics.tdk.com/inf/80/db/fer/...
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95 views

Is it okay to use a 200W PSU as a replacement for a 500W one?

I had a strong PC which is no longer functional at this point. One day while i was using it, it made a click sound and turned off abruptly. It also gave some kind of burnt wire smell which made me ...
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42 views

Bode plot display in matlab

I would like to display a bode plot of a buck-boost converter using Matlab, so I got the figure shown below, If we look closer to the phase plot, we see that it starts from 360°. My wish is to make ...
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42 views

Modulator gain in DCM mode of Buck converter

I am referring this document in Fig 19 the modulator gain is calculated by the formula that results i.e 112.73 with Duty cycle in DCM as ...
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39 views

Calculation of switching transformer at 100kHz

I am not able to desgin transformer for switching frequency 100kHz. It´s easy to desgin usual transformer for 50 Hz. But I´m totaly out when comes to switching transformers. What material should I use?...
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2k views

Tantalum Capacitor Explodes When Engine Starts

I designed a circuit using a SMPS voltage regulator based on the tps65261rhbr triple synchronous buck converter. The circuit is rated for up to 18V. It is connected to a 12V lawnmower battery, which ...
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89 views

Buck Converter PCB Planes

I have a question about PCB copper planes with buck converters. For reference, I'm using the LM2673/LM2679. The parts are identical in layout, utilizing the DDPAK/TO-263-7 with the PCB tab being ...
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42 views

SEPIC converter : why average secondary inductor is the output current?

I can't get the reason the why the average secondary inductor current is the output current. Simulation confirms it's true, as well as documentation. But I haven't found any clear explanation. Sorry ...
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25 views

Use two 250V series cap in APFC instead of single 400V

I have a EVGA 500W PSU with an APFC which is causing spike noises, presumably from the APFC or main switching as they both run in sync controlled by the CM68000TX combo apfc switching PWM chip Noise (...
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38 views

How to connect a second battery to my UPS?

I have a UPS, its battery seem to be dying. Earlier it was giving a backup of 30 min, now it has come down to 10 min with the same load. I purchased a battery of the same capacity 12V 7amp, I was ...
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41 views

Laptop adapter + DC buck/boost converter or buck convereter only?

I have an old laptop adapter, with 19 V - 4.74 A DC output ratings. Suppose I need to draw 3 A @ 11.1 V for one of my circuits. I have been doing some research about dc-dc converters and have some ...
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66 views

Oscillator made from an RC network

I would like to understand how the oscillator of this PWM controller works, and what would happen if I do not apply an RC network but directly a PWM signal generated from a microcontroller for example....
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40 views

Slope Compensation - about the slope value

I read an article on EDN about slope compensation written by Sergio Franco. Here it is : https://www.edn.com/slope-compensation-in-pcmc-dc-dc-converters/ It takes the case of a buck converter. It ...
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79 views

Precautionary Discharging Capacitor went Terribly Wrong | SMPS [closed]

I wanted to check the fuse of SMPS pictured. In order to safely conduct the procedure I followed the discharging procedure as provided in many tutorial videos i.e (connecting the end of the ...
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184 views

DC Gain of the System

I'm trying to design a feedbcak loop compensator and I'm following the instructions on power supply cookbook. Book has calculations for DC gain like equations below: in my situation Vin: 40V-60V and ...
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38 views

Troubleshooting Switch Mode Power Supply

I am trying to troubleshoot switch mode power supply from HP workstation. I have done visual inspection and didnt find any anomalies on the capacitors. I reckon that the culprit might be the fuse as ...
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70 views

Why the television manufacturers (Samsung, Sony, LG, so on) exceed the voltage capacity on led strips (backlight) on TV's?

I dont understand why manufacturers always exceed voltage to backlight tv (led strips). For example i'm fixing a TV with some led burn out. This is the backlight : There are two LED's strips. Each ...
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25 views

PI Filter After Bridge Rectifier - Inductor at Positive Line or Negative Line

I was reading the InnoSwitch-CE Family Datasheet for a design I'm currently working on. At the Circuit Board Layout Recommendations section, it's stated that the inductor should be placed between the ...
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1answer
87 views

Simple 300-400VDC/100A power supply for EV charging from 400V 3-phase/32A

I would like to purchase or build a simple AC-DC power supply, with 400V/32A 3-phase input, and DC output adjustable (by a microcontroller which I would add) between 300-400VDC and upto 100A (not ...
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What is the parameter WDIS (Package power dissipation) in the attached load switch datasheet?

Can anyone confirm what is exactly meant by WDIS? How is it different from maximum power dissipation based on thermal resistance calculation? http://www.silego.com/uploads/Products/product_499/...
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32 views

Have a surface mount device 6G80 package SOT23-6 not able to find datasheet/ or even basic information

I have a cheap power supply that I am trying to modify. The 6G80 appears to be a regulator (driver) chip that drives an N-MOSFET. I do not have an oscilloscope with me, so I am unable to tell if it is ...
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62 views

Maximum AND minimum duty cycle in SPICE converter simulation

I am modeling a Push-Pull Converter in LTSpice and implemented this for a simple voltage feedback PWM control. This works great and I have added a bit on the end that allows for a maximum duty cycle ...
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39 views

Can switching adaptor perform constant current mode?

I want to ask about wall adapter (switching) with 2.5mm jack let's assumed its label as 9V 2A. I saw many tutorial even some product use normal adapter (2.5mm jack) with BMS module to charge Li-ion ...

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