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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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How inverted buck-boost Boosts & Bucks

I am struggling to see how the "inverted buck-boost" converter works the same as a "4-switch buck-boost" converter. In my mind, a 4-switch buck-boost is simply connecting a buck and boost together, ...
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21 views

SMPS 5V without load, fluctuation on load TOP258PN

I am using PI Expert Online (this) to design a smps circuit for 5V, 2.5A output. I already have TOP258PN IC with me so built circuit for that. Change from schematics: I am not using choke and using ...
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22 views

TPS55165Q1 does not work in boost mode

I need a power supply that delivers 12v with an input between 8v and 35v. That's the reason I bought a couple of TPS55165Q1 from Texas instruments. I've made 3 different PCBs with a similar circuit. ...
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45 views

Where should I put my switch - on the enable of my SMPS or the power input?

I'm designing a simple board with a FitiPower FP6717 step-up converter chip (Datasheet) and a mechanical switch (SPDT) to enable or disable the output power. My design for the boost will be very close ...
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76 views

Is this an appropriate smps design? [closed]

I am an engineering fresh graduate with an interest in PCB design. I have been learning KiCAD which is really fun and I enjoy it alot. A friend came to me with the reference circuit attached here and ...
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46 views

Headphone Noise from Laptop SMPS

I have been facing an issue that has been a mystery to me for quite some time, and I wanted to see if someone here can potentially give me more insights on this so I can understand why it is happening....
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56 views

Would this switching power supply work?

I'm trying to design an integrated power supply to use in IoT projects that I'm working on, some including microcontrollers like the ESP8266 or ESP32. In previous projects I've made, power supply ...
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56 views

SMPS: Current Mode Instability (aka “sub-harmonic oscillation”) - Can we ignore it?

Currently I am designing a Constant Current charger for a capacitor which charges it from 0 to 350 VDC using a peak current mode controller. As we expected from simulation, I see there are sub-...
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48 views

Would a compact welder use MOSFETs or IGBTs

Want to know why some welders for a given output are much bigger than others. Already found one of the big reasons is needing to run on 120V instead of 220V How much space does a 220V AC input power ...
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66 views

Inrush Current problem?

I have a 360W 36V Switch Mode PSU which I am using in a garden lighting system I have designed. I'm in the UK so it's running off 240V therefore can supply about 10A. Each section of the ...
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94 views

How much space does a 220V AC input power supply save compared to a 120V one?

For a given output voltage & current, how much space is saved by using 220V instead of 120V input? Specifically, I want to know is it expected for 220V only welders to be much smaller than ...
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22 views

What is Crossing, Overlapping in SMSP Transformer's electrical parameters? [on hold]

Some cheap ready made smps transformer sell on Aliexpress provide details about Primary's, Secondary's, Third's turn, and inductance on primary side. Some give No crossing, some give crossing, ...
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71 views

SMPS voltage drop in 230v ac to 5v dc flyback

I am building a SMPS circuit from a switching IC. This IC has feedback and enable pins for timing and current calculations respectively. Transformer Data: (10 pin 1-5, 6-10) primary: 1-3 - 60 turns, ...
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64 views

Conditioning input power supply on PCB

I have had issues in the past with using too close of an input power supply to the max rating of my main power regulator causing failures. For example, I used a 24VDC supply with a regulator with an ...
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38 views

Buck Converter - Closed Loop - Effect of decreasing inductance and increasing capacitance

Output voltage as a function of output current is plotted from oscilloscope data for a closed loop buck converter. Switching frequency is kept the same in both the cases. CASE 1 : Inductance = 2....
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49 views

Choosing power supply for device [duplicate]

This question is not Duplicate I am building a device which has a Raspberry Pi 3b +, custom Atmega328-PU or AU circuit (homemade Arduino), ws2812 SMD LED Arrays. Here, Raspberry Pi will provide ...
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44 views

Weird current in Push-Pull converter for high voltage multiplier

I have a push-pull converter driving a Villard-type voltage multiplier. The converter is built as naive as it could be: Two stacked MOSFETs with free wheeling diodes for the push-pull half opposing ...
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2answers
95 views

How find the optimal frequency of a high frequency transformer

I have disassembled a "Chinese" power inverter, I found a High-Frequency Transformer, with no label on it. I would like to make an inverter using this transformer to generate the High voltage to feed ...
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1answer
40 views

Regulate 0-6V output

I need to control output from 0-6V at max 1A (~0.8A). Looking at the datasheet for LM25010 it looks I could control R1 and R2 feedback resistors and achieve just that. Is it possible to get that ...
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37 views

SOT23-3 part identification - marking 12A1G

I have a SOT23-3 device with marking 12A1G. It is used to power Wifi module in a smart dimmable LED driver. Can you share details of this chip? It is used as a control with integrated MOSFET in a non-...
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2answers
39 views

Isolated Power Supplies for Inverter Gate Drivers

I am using a 3-Phase IPM IGBT Inverter Module in motor driver. This module has built-in gate drivers which require 4 Isolated power supplies for their operation. In all I have to design 5 Isolated ...
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58 views

How can I get this 12v motor to run smoothly, and is it set up safely?

This is my first attempt at electrical engineering, so I'm sorry if this question seems basic, I couldn't seem to find answers anywhere. I want to wire a 12v motor to an on/off switch and power with ...
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49 views

210v DC CV/CC supply

I have an old variable power supply that consists of a multi tapped transformer, a bridge rectifier and a choke. The transformer has two sets of taps on it, 6 coarse and 6 fine, giving 36 voltage ...
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65 views

Switching regulator not suppressing variance in input?

I am having a little problem with my switching regulator, based on a AP65211A and here is my schematic: Parts: ...
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2answers
54 views

Hold-up time in SMPS

I know the definition of Hold-up time in SMPS, and how to calculate the bulk capacitor. But I am wondering if someone can explain me how we define the hold-up time (sometimes 10ms, sometimes 16ms,...)?...
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92 views

Why does voltage change with load in buck/boost converters?

I recently learned about buck and boost converters. Both are switched-mode power supplies. Until recently, I had the impression that the duty cycle and input voltage determine the output voltage for ...
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30 views

Is the input voltage on power adapters RMS voltage or peak AC voltage?

For example, would a laptop power adaptor with a voltage input of 100-240V ~ be safe to use in a country with 230V RMS wall voltage? Thanks in advance!
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sawtooth generator for MCP1630

when using MCP1630V to design a buck converter in voltage mode control, is it preferabale to get sawtooth generator from the drive output pin or from the oscillator input pin? From the timing diagram ...
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1answer
78 views

Switching power supply toroidal heats more than 100ºC. Is it normal?

I’ve got this 48V 10.4A generic chinese switching power supply to power my mini lathe’s controller and stepper motors. The two steppers draw when working just 1.5A max each. And the controller 0.5A. ...
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2answers
73 views

Why the replacement of 7812 with R-78E12-0.5, DC/DC makes the circuit not working?

I have this simple surge protector and soft start inside the PSU. My transformer is out of its specifications yields 21.3V after bridge rectification. And 0.1A load (12V fan for cooling pass ...
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22 views

Limiting current in a NCP3020A switched DC/DC buck converter

I want to design a 12VDC to 5VDC converter using a NCP3020A. As my application has nothing special, I should follow the topology of the Typical Application circuit, and reapply the formulas in the ...
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22 views

Buck converter design using MCP1630V

I have already designed a buck converter with the following specifications using an MCP19035: Vin=14V, Vout=1.8V, Fc=63kHz(Crossover frequency), Vref=0.6V, Iout=10A step load High IOH=7.5A step ...
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41 views

MCP19035 buck converter controller

I'd like to design a buck converter using MCP19035, I've gone through the datasheet of this component and and the design procedure using it. In the datasheet, it says that the component provides Two ...
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33 views

How do voltage and frequency fluctuations affect switch mode power supplies?

I have a high power (6000W) sub-woofer amplifier which has a switch mode power supply. This amplifier only worked few hours before it stopped working and it looks like an issue in the power supply. ...
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28 views

Solar panel voltage with buck converter and mosfets?

If the input voltage of the solar panel as Vin in the picture below. if Vin is in the range of 10 V to 37V.The average voltage value in the node in yellow during switch 1 is on and switch 2 is off is ...
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1answer
44 views

COB lights using 4 aaa batteries

I bought a few COB lights from Harbor Freight, they look like light switches. I would like to hook them up to a wall mount power supply, I think they are wired in series. Also, I would like any ...
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1answer
120 views

RT6224D-based step down circuit yields 0V - why?

We received a set of prototype boards. They have a DC power supply input feeding into a step-down converter, which is built around an RT6224D. It is supposed to deliver 5.0V. The circuit is almost ...
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1answer
45 views

Gain deficit and phase margin at crossover

I went through an exercise of the following specifications: A voltage mode buck converter working in CCM mode works with: \$V_{in}\$ min = 10V, \$V_{in}\$ max = 20V \$R_{load}\$ min = 2.5 ohm \$R_{...
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1answer
24 views

Switching Regulator[AP65211A] Issues: Higher Voltage then expected at minimal load, drops to 0 with small load

I normally just use linear regulators in my designs and this is why... Switching Regulator in question: https://www.diodes.com/assets/Datasheets/AP65211A.pdf Circuit: Board Layout: The problem I ...
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2answers
73 views

Does polarity of scope probe matter when measuring ripple of the power supply module?

Measuring ripple of 28V/12V power supply module across +/- output pins. Does the probe tip have to be placed at +pin and probe gnd to -pin, or it can be reversed? Having inverted readings when ...
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0answers
27 views

SMPS mains hum on guitar rig

My guitar rig consists of Guitar -> Audio Interface (Steinberg UR22) -> Laptop (via USB). I listen to the (processed) audio using headphones connected to the audio interface. ISSUE: When the ...
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1answer
113 views

What is the minimum and maximum voltage that can applying at input?

I have a status circuit (got from google ) as shown Could you please tell me what is the max/min voltage that can possibly apply at the input(safe limit)? If it exceeds this range what happens? How ...
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1answer
87 views

device suitable for generating AC voltage?

I want to test my circuit with different types of inputs. Is there any device or equipment that I should buy for generating voltages? I would like to be able to adjust the voltage and current by ...
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2answers
53 views

Direct connection or using capacitor when shorting PSU's DC negative terminal to earth terminal?

I have read and then observed that for reducing the 50Hz related noise, tying the -DC terminal of an SMPS supply to the earth terminal woks well in some cases when. Below shows a direct path by a wire ...
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0answers
30 views

Ripple in output voltage

I am working on an Active Clamp Forward converter. Schematic is given here: Specs: Output voltage-5V Input voltage 26..42V frequency=500KHz Output power=10W It is working fine in open loop, but in ...
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1answer
60 views

SMPS electrical noise issue

1I'm using class 2 medical graded SMPS in our device. So earth connection not recommended. When connecting SMPS to load (contains capacitive touch LCD), touch function is affected by SMPS noise. When ...
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1answer
31 views

Is there a minimum current drain to use LM25011 of TI?

Using LM25011 as switching voltage regulator to power a board with wide range of current drain rates. Input of 24v; Output of 5V; Drain current between 5mA and 1A. Is this component suitable to this ...
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1answer
56 views

Topology choice for wide-output-voltage-range SMPS

I'm intending on building a off line (230VAC), 50W, isolated, constant-current switch mode power supply. This by itself is not a big challenge with the plethora of application notes and examples ...
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1answer
32 views

how to switch to backup battery when power fail?

I have a project running with MCU supplied with a 24V power supply regulated via an SMPS to 9V also, I have Li-ion battery pack 9V how to connector these two sources to run the MCU with battery pack ...