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.

242 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
4
votes
1answer
210 views

How to cure SMPS output to get upset by a switching device

I have been having ringing spike issues at the output of SMPS power supplies. I don't know what is this phenomenon is about but it is definitely related to switching devices on the same electrical ...
4
votes
0answers
410 views

4 switch Buck-Boost, boost not reaching designed current

I am working on a power supply that regulates the voltage coming out of a 3S LiPo battery. The buck portion of the circuit works fine and outputs 5+A with acceptable ripple. The Boost portion instead ...
3
votes
1answer
83 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....
3
votes
0answers
93 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 ...
3
votes
0answers
70 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: ...
3
votes
2answers
62 views

What capacitors are proper to use for input of AC DC converter?

I am trying to build an 120 AC to 15 DC @ 200 mA converter using a Power Integrations LNK3206P. Using the full bridge rectifier setup on Table 10 from application note AN-70, Cin1 and Cin2 should each ...
3
votes
4answers
4k views

SMPS output voltage too low - what to look for?

I have an old switching power supply for HP 712/60 workstation (+5V, +3V3, +12v). It was working about ten years ago when i've last tried to boot the system, but now one of the output voltages is at ...
3
votes
2answers
275 views

Why do I get high DC current in grid tied inverter output?

Edit: Added gating signal waveforms. Changed some of the graphs, I accidentally put a test circuit waveforms the first time. Current is not that high but offset is there and current is high for a ...
3
votes
1answer
571 views

Is it possible to use Microchip's ZCD (Zero cross detect) circuitry in an isolated SMPS?

Let's say you have a device which is fed by AC line voltage and features an isolated SMPS. The switcher outputs 5 VDC, and that powers a PIC micro. I'm curious how is the Microchip's ZCD (Zero cross ...
3
votes
1answer
614 views

IRS2153(1) half bridge giving irregular output

I'm following standard design recommendations for a IRS2153(1) half bridge driver in the following setup: The problem is that the output (measured at the joining net of Q1, Q2, L1, pin 6 and C3 ...
3
votes
0answers
1k views

Can I use a TVS diode to remove spikes in SMPS?

I have an almost working Half-Bridge SMPS that has some ringing in the output like this (not the real output, just and image I found): I have eliminated almost all the oscillation using a snubber ...
2
votes
0answers
42 views

Can a Capacitance Multiplier be used with high voltage outputs?

I am designing an SMPS which two output voltages of 5kV and 2.5kV. My transformer is split into four equal sections, each feeding a FB multiplier, connected in series to form the final voltages. ...
2
votes
0answers
37 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 ...
2
votes
0answers
34 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 ...
2
votes
0answers
196 views

Large negative current spike in N-Channel MOSFET source when turn-off

I am working on repairing a power supply board of a LCD TV (200W power), more specifically, the PFC section (active power factor correction). See schematic (adapted from here): I've replaced some ...
2
votes
1answer
102 views

Questions about a design for an SMPS post regulator filter circuit?

For minimizing SMPS ripple and especially noise, I’m trying to make a small interface which is a post regulator cascaded after an LC filter. I have come across some papers related to this topic and ...
2
votes
0answers
51 views

Can I generate following voltage waveform with single PWM FET?

I am designing power supply which must output following voltages at a maximum of 1.5 A stepped down from a 24 V DC supply. 24 V 13-15 V 0-5 V Waveform for one of the inputs requires following ...
2
votes
0answers
67 views

Need to resolve a trasient on the Output of power supply

I am designing a fly-back SMPS AC/DC topology power supply, i mount the PCB and when i tested it with a restive load (hot air stove 230V@600Watt-50Hz) y see that on the DC output appears a transient ...
2
votes
1answer
114 views

Cuk converter implementation

I have come across this article: https://www.powerelectronics.com/power-management/step-down-dc-dc-converter-eliminates-ferrite-cores-50khz-enabling-power-supply-chip That describes the Cuk DC/DC ...
2
votes
0answers
118 views

55-650V to 5V DC/DC convertor design

For an application I am building I need a custom DC/DC convertor that can convert a voltage ranging from 60V-600V to a contant voltage of around 5V. Using the TI Webench with the paramaters Vin_min = ...
2
votes
0answers
162 views

SMPS Layout, capacitors in parallel placement

I'm laying out a buck converter based on the TPS54308, and the datasheet recommends the following, which I'm trying to replicate: Webench (the interactive design tool by TI), however, recommends 2 ...
2
votes
0answers
465 views

Differerent connection for Y-capacitor (EMI filter)

What is the difference between these two connections Y-capacitor (EMI filter)? *high-voltage side to isolated 12V DC output *isolated 0V DC output rail and a "GND" Could you tell me the raison of each ...
2
votes
2answers
238 views

Momentary switch for power?

The only switches I have every worked with are basic switches with on/off state, but I want to be able to add a power button to my project that is just like the power button on a cell phone. (hold for ...
2
votes
0answers
131 views

Badly designed USB power supply?

Purchased a device from an online retailer (fairly well known and reputable), they ship from internationally and often include a local USB wall charger to replace the one in the box of their goods. ...
2
votes
1answer
266 views

SMPS output noise: Why is it amplified further away from the output capacitor?

Well this is just a general question about switch mode power supplies, but i have recently built a buck converter, and read that it is very important where in the circuit you place your probes, to ...
2
votes
0answers
495 views

Advanced ATX Power Supply Modifications

I know there are multiple tutorials and questions regarding converting an ATX power supply, new or old, to a benchtop power supply for projects. I'm fully aware of how to make the basic conversion to ...
2
votes
0answers
163 views

How does this diode improve the common mode conducted noise?

This image was taken from UCC28881 (page 16) The desciption in the body says: A half-wave rectifier is chosen and implemented by diode D2 (1N4937). It is a general purpose 1-A, 600-V rated diode....
2
votes
1answer
66 views

Relay+SMPS = Noise in RS-485 bus

I designed a board with a microcontroller (Atmega328), 3 relays and a RS485 transceiver. The relays control SMPS LED drivers (Meanwell LPF series). The system consists of 10 boards, each one ...
1
vote
0answers
42 views

Flyback Converter Oscillator

I am posting a small circuit I have found in a commercial power supply. It is a flyback converter transforming AC mains into 12V DC. I am having trouble understanding how transistor T1 is actually ...
1
vote
0answers
50 views

Can MIC4102 be used to drive Boost Converter

I'm trying to design a high-power Buck-Boost converter, which is meant to convert a 45-63V input voltage into a "constant" 48V. The application requires quite high currents (up to 20A continuous). The ...
1
vote
1answer
73 views

Combining non-isolated switch mode power supplies in parallel into a single supply

I'm trying to combine several SMPSs each having a ~350VDC output @100mA each. Background: Purchased an unused batch of small DC->DC SMPSs in good industrial quality. Unfortunately they're too weak ...
1
vote
0answers
14 views

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 ...
1
vote
0answers
30 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 ...
1
vote
2answers
57 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 ...
1
vote
1answer
79 views

How do I connect an LED with floating DC voltage?

I want to connected an LED at the output of 500V DC. This DC power supply is made by 3phase DC rectifier and is floating. I would like to have a display on the front panel of the supply which will ...
1
vote
1answer
65 views

What is the operating frequency of this IC?

It is the LT3751 High Voltage Capacitor Charge Controller, datasheet. I am trying to calculate the required value for the input capacitor for my application, but the datasheet does not clearly ...
1
vote
1answer
131 views

5V Switching Regulator Problems

I have a circuit with two supplies. A 19v supply for stepper motors, and a 5v supply for driving the ATMEGA644, 3 stepper motor driver daughter boards, a bluetooth LE daughter board, and 2 ws2812b rgb ...
1
vote
0answers
52 views

Cant recognise a Damaged component of switched-mode power supply

I was repairing an smps ATX power supply I found a damaged component that I could not it recognise. I thought it's a power switch since it was mounted to a heat sink along with tow D13007 NPN power ...
1
vote
0answers
22 views

Which power converter topology has higher benefit of EMI/EMC?

Which power converter topology can be best suited for EMC compliance for small power converter to be used in LED lighting products. In my context I'm using a 5W non-isolated AC-DC converter which is ...
1
vote
0answers
76 views

2 Switch Forward Converter Volt-Sec/Charge Balance

I am attempting to design a 2 switch forward converter. I understand how to do the volt-sec balance and charge balance when the converter is as shown in the ideal 2 switch forward converter below. I ...
1
vote
0answers
138 views

Reducing AC/DC adapter (SMPS) output voltage

I have a AC/DC adapter P-1650-22 (used to power a notebook) laying around. I would like to use it for other purposes, i.e. as a constant voltage source for LEDs. The problem is, that the output ...
1
vote
1answer
148 views

SMPS Flyback transformer selection

I am trying to design a SMPS for a project (I have to make a custom one for integration purpose). This SMPS have universal input (85-265V AC at 50 or 60 Hz) and an output of ideally 53V (but it can ...
1
vote
0answers
51 views

What factors should I consider when choosing a high amperage power supply?

I've searched around, but I haven't found an answer to this particular question yet. I'm building an elecromechanical project which requires somewhere around 60 Amps at 12 Volts. While this may not ...
1
vote
0answers
27 views

Designing a CCM Boost PFC rectifier circuit

I am working on designing a CCM Boost PFC rectifier circuit, supplying up to 2.8kW at 400Vdc nominal, while taking 230Vac, 50Hz controlled via negative feedback in the average current control mode. I ...
1
vote
0answers
179 views

switching between two similar power sources - solar battery and cr2032

I'm trying to create a circuit powered by two alternative power sources. The first one is a Li-Po battery charged by a solar panel and the second one - standard 3v battery, ie. CR2032. The circuit ...
1
vote
1answer
81 views

Determining Phase Boost needed to Compensate SMPS

I'm attempting to find the Control-To-Output Bode Plot (open-loop) of a SMPS designed around the TPS54160 so that I can design the type II compensator. The first step in designing a compensator is ...
1
vote
0answers
40 views

DC DC converter opamp compensation

I have simple doubt. I am making a closed loop DC DC converter flyback, I am using opamp for compensation. It should be a single input single output network. Input voltage is 24-32 volt, output is 5V ,...
1
vote
0answers
109 views

Optimal duty cycle in Forward converter?

So as far as I understand the Forward topology: The duty cycle set by the controller in CCM mode is constant assuming constant input voltage and constant output voltage. The duty cycle is independent ...
1
vote
0answers
42 views

How to generate and/or improve this power distribution for these 4 subsystems?

I am trying to design a system that is powered through a 28V wall adapter and a 6S cells LiPo battery. The system has a subsystem that takes care of the balanced charge, coulomb counter, charge ...
1
vote
0answers
46 views

Sharing a 5v Supply

I want to deploy a Pi Zero in a weatherproof box. I need to provide 5v DC for the Pi and an 8 channel Relay Board and two 5v DC pumps. I have a 5VDC 5A 25W single output power supply that seems ...