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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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2
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2answers
2k views

SMPS minimum rating / type calculation - how?

Looking for some help in defining the specifications of SMPS required to power an embedded project around (rather surprisingly, may be), Intel Atom motherboard. The plan is to run the system fan-less (...
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1answer
1k views

How might I wire a split pi converter to transistors as to maximize output voltage?

I was looking into various dc-dc converter designs, and I was interested in the split pi converter. As a start, I just want to maximize the output voltage. I know in theory, the output voltage could ...
6
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1answer
7k views

Cleaning up a 5V Switching DC-DC converter for low noise 5V output

I have a project that I have to hook to a 5V bus coming from this DC-DC switching converter. I need to clean this up to use with a logamp (LOG114), photodiode, and ADC (ADS8519). I would also like ...
3
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2answers
171 views

how switch mode regs work - am I correct

Hi I just watched a video tutorial explaining how switch mode regulators work. I want to confirm I've understood correctly. The inductor used in a switch mode power supply is there to provide power to ...
3
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2answers
1k views

DC supply for control circuit of a DC-DC converter?

I have a switch mode DC-DC converter assignment which is supposed to convert 36-72V input DC voltage to 9V DC voltage. The circuit I'm working on contains a control circuit (implemented with a custom ...
6
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5answers
2k views

Determine efficiency of converter

I would like to determine as accurately as possible (ideally within an error limit of +/- 0.25% or better, but I guess that's nigh impossible) the efficiency of a converter, using a simple method. I ...
0
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2answers
852 views

Computer SMPS is working with high electric shock spreading [closed]

Sir, I have a ATX SMPS, today its working and connected LCD monitor will be blinked anonymously, i touch the cabinet I get a electric shock from the cabinet, also CPU working and Its have high ...
4
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3answers
8k views

LM2596 Voltage Regulation Problem

I am trying to implement a switching voltage regulator from 7.2V to 5V with LM2596 by HTC Korea. Since I don't need an adjustable regulation, I chose typical application circuit from the datasheet ...
6
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1answer
9k views

Why do we need 100nF cap in the output of an SMPS?

I was looking at Micrel AN-53 and I have noticed that in a circuit in the first page (circuit is below), at the output of an 400KHz, 27V, 7A, 180W boost converter, there are two 680 uF, two 10 uF and ...
2
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2answers
1k views

How can I improve this SMPS design?

In: 21-32V Out: 12V, 3A Working Frequency: 300 KHz Controller IC: FP5138 from Feeling Technology MOSFET: IXTP44N100T from IXYS Schottky Diode: MBR20100CT from ON Semi The MOSFET and the diode ...
6
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1answer
2k views

Type 2 compensation network

I'm working through the excellent text on SMPS design "Switching Power Supplies A to Z", by Sanjaya Maniktala. Right now I'm reading the section on the feedback loop and stabilization. As a first-...
1
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1answer
808 views

Help with design of current load sense circuit

I'm having a bit of trouble figuring out a suitable method to sense when some LEDs in my Garage Door Opener are on. This is a continuation of this project I asked for advice on recently. However I had ...
2
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1answer
733 views

How do I determine the requirements of a switching FET?

A part we're using in a half-bridge LLC soft-switching DC-DC converter is getting hard to find (STW20NM60, 600 V, 20 A, 0.25 Ω, 192 W), and I need to find a replacement. What parameters do I need to ...
2
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1answer
1k views

Criticize SMPS PCB Design

Yes, it is me again with a PCB Design. I am learning a lot thanks to you. This time, the specs are; 10-32 V input 35V 4A output Boost converter The controller IC is LM3478. Schematic & PCB: Q1 ...
2
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1answer
2k views

SMPS PCB Design Critic 3

Can you critique my design? After finishing my 5v part, I've added the 35V part, too. 10-32V to 5V 1.2A SMPS Buck Regulator, the IC is IFX91041 from Infineon. 10-32V to 35V 4A SMPS Boost Regulator,...
3
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5answers
8k views

Can two ATX SMPS be connected in series to get +10 and +24V DC

Can two ATX SMPS be connected in series to get +10 and +24V DC (from 5V and 12DC output of each SMPS) Needing lots of current at 24V with atleast 5A so cannot use -5V or -12V inside SMPS as negative ...
2
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1answer
1k views

SMPS PCB Design Critic 2

Thanks for your patient help, I am learning a lot. This is my (final, I hope) re-designed layout. What do you think? 10-32V to 5V 1.2A SMPS Buck Regulator Design. The IC is IFX91041 from infineon. ...
21
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6answers
26k views

Can the noise of any switching PSU be attenuated if I put linear regulator before the output?

A friend told me that noise of any switching PSU can be attenuated if I put linear regulator before output. Is that true? For example, if I want to power a +-12 V op-amp for an amplifier, I can ...
9
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3answers
4k views

SMPS PCB Design Critic

Oldest versions of this post can be viewed through this link. This is my re-designed layout. What is your view again? 10-32V to 5V 1.2A SMPS Buck Regulator Design. The IC is IFX91041 from infineon. ...
6
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2answers
802 views

Crosscoupling in SMPS PCB layout

I have been reading this application note from National and I have a question about this phrase: ... traces carrying switching currents/voltages must also be kept away from ’quieter’ traces to ...
7
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3answers
7k views

Why is SMPS controller IC failing?

I'm back to diagnosing power supply failures, in an LLC resonant SMPS based on the L6598, from a 400 V PFC supply with ostensibly 400 W output. I'm new to SMPS, and learning this all as I go, and the ...
1
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2answers
4k views

Switching Regulator: How to determine maximum inductor current?

I am trying to design a buck/boost converter with LTC3780 chip from Linear. My spesifications are: Vin = 6 to 32V Vout = 24V at 100mV ripple Ioutmax = 2A Frequency = 300kHz However, in the ...
9
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2answers
16k views

Calculating Power Loss in Switching Power Regulator?

I am new to the construction of DC/DC power supplies (still a university student) and have built basic supplies using simple linear voltage regulators. I have recently discovered the world of ...
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2answers
922 views

Step up DC voltage from 12-24V to 60V

I need to provide a 60V/1A power source from a 12-24V input, -40 to 85 degC temperature range. Parametric searches for DC/DC converters at a couple online vendors don't seem to be turning up much. I'...
3
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2answers
4k views

Adjustable SMPS using MC34063?

Is it possible to construct an adjustable output switching power supply based on the MC34063? I read over the On Semi datasheet and app notes but didn't see any examples of an adjustable output ...
22
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6answers
4k views

What are some common/popular/go-to switching voltage regulators? [closed]

So I've used the popular linear regulators (7805, LM317, LD1117, etc), but I'd like to learn more about switching regulators. Are there any "must have" switching regulators out there that are as ...
3
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5answers
3k views

Variable resistor that can handle hundreds of watts?

We have some big resistor test loads, like 8 Ω 250 W loads for simulating speakers: Are there also big variable load resistors for testing power supplies? What are they called? If not, what do ...
2
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1answer
2k views

Setting correct operating frequency for LLC resonant SMPS

I need to figure out if an LLC half-bridge resonant SMPS is designed (more or less) correctly. I am not an SMPS designer, and neither is the manufacturer, so I'm just reading a bunch of app notes and ...
3
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4answers
1k views

Building SMPS using L4960: How does the choice of inductor affect circuit operation?

I've decided to conquer my fear of switched-mode power supplies and build one. Right now, I have a L4960 regulator. Its datasheet recommends use of a 150 μH inductor rated at 5 A. My problem is that ...
3
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2answers
763 views

What probems may arise with a 200V rated relay conducting 1000V 1A?

I am going to use a DPST relay to pass a 1A 1000V DC signal of an ESD Human Body Model simulator circuit through it. I have see many relays, they share a property like maximum DC switching for ...
1
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3answers
1k views

Switching Voltage Regulator with WiFi Ethernet Controller Bad?

I a working on a circuit that has components that need 3.3V and 5V. My power input is 12VDC and can not be changed. The 3.3V components use about 510mA of current and the 5V components use about 155mA....
9
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4answers
3k views

Different ways to digitally control an adjustable SMPS

I want to make a battery powered, adjustable SMPS for use in situations when I cannot have an outlet near me, so I would like some more information or suggestions about this topic. The SMPS chip I am ...
5
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4answers
3k views

Short circuit protection for a boost converter

Is it possible to add short circuit protection to a boost converter? My initial instinct was no, as the switch does not directly control the input to the inductor and this means the minimum output is ...
5
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4answers
384 views

Obtaining 15 V from a single lithium polymer cell

I want to get 15V output from a 1 cell lithium polymer battery which has a voltage range of 3v-4v. I am thinking about using a 34063 to accomplish this. But will this work over a 1v range or do I ...
3
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3answers
3k views

Buck converter with feedback loop

According to this site in a buck converter with voltage mode control the duty cycle is set directly by comparing a voltage ramp to an error voltage. I agree with that. But this is where my headache ...
0
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3answers
273 views

Is there any way to acquire -12 V from +12 V?

Is there any way to get -12 V (DC) using only: +12 V DC Ground OPAMPs Resistors Capacitors Inductors Diodes
6
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3answers
1k views

Choosing output filter inductors for switching power amplifiers

Class D PWM switching power amplifiers use an LC filter at the output to filter out the switching harmonics: Other than the inductance value, what properties are important for this inductor? What ...
6
votes
1answer
11k views

TL431 as a comparator?

One of the things I've noticed in a few power supplies is the use of a TL431, a voltage reference, as a comparator of sorts. It seems to be set up in a configuration where when the voltage across it ...
6
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9answers
4k views

Would this work? Using a computer SMPS as a DC-DC converter

I have this crazy idea of using a computer SMPS with active PFC boost to take high voltage DC battery banks (144V+) and drop it down to 3.3V, 5V and 12V. Here's my thinking: the power supply ...
4
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2answers
1k views

Should I select components based on peak current, RMS current, or average current?

I am designing a SEPIC supply around an LT3757. The MOSFET will have ~6.5A pulses with a strange ramping pattern (see image), but the RMS current is only 3.38A and the average current is 2.60A. ...
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3answers
871 views

Using a digital potentiometer with a SMPS?

Is it possible to use a digital potentiometer with an SMPS, to adjust the voltage? I'm looking at one with a 2 MHz -3dB bandwidth. What does this mean for a 300 kHz switcher?
2
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1answer
494 views

Critique my SMPS buck design, take 2

After getting some helpful critiques from my original post; Critique my SMPS buck design I worked on my design and made a few major changes. L1: 3.3uH 2A inductor C1: 10uF 25V ceramic cap C2: 0....
16
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1answer
14k views

How important is self-resonant frequency for an inductor when used in a fast (~3MHz) buck SMPS?

I'm using the LM2734Z, a 3 MHz buck regulator. It's really fast which means it has a small inductor. One of the things I'm wondering is how important is the self-resonant frequency of the inductor? I'...
7
votes
3answers
1k views

Critique my SMPS buck design

I'm using an LM2734 buck regulator to get +3.3V at 400mA. The datasheet is unclear on how to lay out the supply, so I tried to follow some common sense, keeping all power traces short where possible. ...
5
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5answers
25k views

How much current do you require in Arduino and embedded systems projects?

How much current do you require in Arduino/Sanguino or other embedded systems projects? After responding to the LM2575 inductor question I started to take a closer look at the TI power DC-DC ...
8
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3answers
2k views

DC boost for low voltage?

I have a project where I'd like to convert a 0.5 V, 800 mA supply (a solar cell) to at least 3 V with as much efficiency as possible. I've seen DC boost converters, but all the ones I've seen are ...