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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29 views

Switcher discontinuous mode - potential EMI problem

I need to design switching mode power supply with input voltage range of 25V-45V and output voltage 5V@2A. Power supply must be ON while the system is in sleep mode(~1mA consumption). In that ...
7
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1answer
184 views

What does the Y capacitor in a SMPS do?

It seems that a well-designed SMPS has a capacitor connecting the ground planes of the primary and secondary sides of the transformer, such as the C13 capacitor here. What is the purpose of this ...
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2answers
47 views

Replace Li-Ion battery with buck converter?

I have a remote control for a GoPro camera. The remote runs off a 3.7 v li-ion battery. The remote draws about 100 mA. I want to extend its usability by supplying 12 v power. The camera cable takes ...
3
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2answers
58 views

Low cost 30A 24Vto12V stepdown converter [duplicate]

I'm trying to design a 24V to 12V step down converter. Power efficiency is not that important to me, but I want to come up with the cheapest solution possible. I don't need isolation neither. So I ...
0
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1answer
41 views

two switch forward inverted transformer

How does it happen if I use an inverted transformer in a two switch forward converter? please consider practical conditions. regards. ras
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0answers
21 views

the best book to practice [closed]

I am looking for a book that would let me practice the chapters of Principles of Measurement systems by John P Bentley. I am looking for a book that has all the contents of the this above mentioned ...
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5answers
1k views

Why are charge pumps only used for low current applications?

Typically the most expensive (and hard to get) elements in a SMPS are the inductors. Thus I was wondering if it's possible to use inductor-less switching mode power supplies (i.e. charge pumps) for ...
0
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1answer
49 views

flyback converter transformer selection

I am trying to design an isolated dc dc converter. Now, my input is approx 20V and I need an output of 7V at the final output. I understand that I need a PWM controller that is approx 100kHz or so. ...
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3answers
604 views

What does reverse diode on NPN symbol indicate?

I've been scavenging parts from compact fluorescent (CFL) bulb ballasts just for the sheer joy of getting something for free. Plus, I'm all into inductors just now and there are some nice little ...
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1answer
65 views

How calculate inductor discharge time through LED?

UPDATE Overnight I realized I'd been sleeping as I read part of the textbook I've been using or at least didn't quite fully grasp the purpose of inductor volt-second balance. I added the results of ...
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4answers
53 views

Measure indcutor ripple current in a SMPS

I need to measure the ripple current in a buck converter. In general, I add leads to the inductor and use a current probe. My issue now is that the inductor I am using has such a low inductance that ...
0
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4answers
88 views

Short circuit when probing live ATX power supply primary section with voltmeter [closed]

I was probing around an old ATX PSU to inspect voltage levels in the primary section. The first 15 minutes went smooth (bridge rectifier inputs, big caps, Power IC Vcc, etc..) but as soon as I probed ...
10
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1answer
465 views

What does a black bar across transformer symbol designate?

What does a black bar across a transformer symbol designate? This appears in a power electronics context, and in particular in this case with substituting a DC transformer as an equivalent circuit ...
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4answers
96 views

Do I need a galvanically isolated step-down DC-DC converter to power my digital electronic from a battery pack that powers also the electrical motor?

I have a battery pack with lithium ion cells. The battery pack has a maximal voltage of 84V (it goes from 84V to ~50V -> depending about the current state of charge). I use this battery pack to ...
3
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4answers
351 views

Is it possible to eliminate output ripple of SMPS's by using two parallel SMPS's to produce outphase outputs to each other?

simulate this circuit – Schematic created using CircuitLab Obviously it can not be that way. But why? Imagine one converter with a phase detector of its switching frequency, outputs a ...
3
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2answers
64 views

DIY DC Blocking Capacitor for oscilloscope

I'm studying switching converters and want a bench setup that will allow me to reliably observe the various voltage waveforms (output, inductor, switch) on my oscilloscope. I discovered pretty ...
14
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2answers
469 views

How does this wall-wart switcher work?

UPDATE I've provided a full outcome report in one of the answers below with an updated schematic and description of the operating principles as I've come to understand it. I'm studying switching ...
1
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1answer
73 views

What does 'g' in switching converter input voltage \$V_g\$ stand for?

I'm studying switching converters and the input voltage of a Buck, Boost, or whatever is designated as \$V_g\$. I've racked my brain (and also searched Google), but I can't work out what the 'g' could ...
1
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2answers
40 views

Overvoltage protection after SMPS

I have design a switching mode power supply which converts the 5V to 3.3V for microcontroller and some other peripherals ICs supply. The chips is TI's LMR10520Y, a low input range step-down switching ...
0
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1answer
50 views

Can tranformerless inverter topology be used in UPS with a regular battery (12V 7Ah)?

While searching for transformerless inverters in the IEEE site, most of them seem to be about grid connected Photovoltaic inverters. Removing transformers will increase the efficiency at the cost of ...
1
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1answer
49 views

Buck controller MOSFET drive voltage

I am trying to design a switching regulator for LEDs, which uses the LM3405 as controller. This IC uses the BOOST pin to power the internal MOSFET driver, which controls an internal MOSFET. There are ...
0
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1answer
72 views

Buck converter with an IR2110

I'm making a buck converter with the following characteristics: Input voltage: 24V Output voltage: 5V-20V Max current: 5A *Constrains: The transistor driver must be an IR2110 I have the ...
0
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1answer
40 views

How to test a ir2110?

I've this circuit, I haven't connected the transistor yet, I want to check the proper function of the circuit before so I don't burn nothing. What is the correct way to check the output signal, ...
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2answers
39 views

3 different regulators at the output of an SMPS

Hello: I'm a beginner in electronics, so I don't know if my question is a stupid question. I have a chinese commercial SMPS rated at 24VDC 15Amp 360W output and I need to get from this output 3 ...
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2answers
120 views

Ghost? voltage on lamp outlet when turned off (72V/50V) [closed]

I have a < 10 year old house. And today I wanted to use the 2nd lamp outlet in the living room, and even though it was turned off, I got hit by electricity. I am in 230V, 50Hz country (Measured ...
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3answers
58 views

Core loss appearing in buck converter ripple current

I have been told (and have also seen experimentally) that an inductor with a high core loss will introduce "glitches" to the ripple current in a switch mode power supply. I have tried researching ...
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0answers
58 views

Help finding PWM IC with marking on device '0L346' not sure weather it starts with 0 or O. package of device is sot23-6

I was troubleshooting my mobile charger where I found PWM IC faulty. However I couldn't find it's datasheet for ordering information. The device marking is 'OL346' not sure if it starts with numeric ...
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1answer
39 views

What rating should a spade electrical connector have to power an eTopxizu 12v Dc 30a 360w Regulated Switching Power Supply from a US wall outlet?

I'm looking to power a Prusia i3 3D printer with RAMPS 1.4 from an eTopxizu Dc 30A 360 W Regulated Switching Power Supply, at the moment I'm looking at how to connect it (safely) to a United States ...
1
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2answers
87 views

Power Supply for Home Automation - SMPS vs Coil Based

I need to design a power supply for my home automation products. I need +12V DC (1A) and +5V DC (500mA) respectively for two different products. One option is to use a circuit with coil based ...
4
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1answer
125 views

Are these EMI noises?

I have always heard about EMI noises but have not really meet them or measured them. Our system composes a MCU running at 168MHz and a 16-bit DAC which is supposed to provide high-precision voltages ...
2
votes
1answer
47 views

LTSpice SEPIC design low freq ringing

Further to the SEPIC design I asked about in LTSpice SEPIC simulation current spikes, I have a new problem. The output voltage is OK and the inductor current waveform looks much better but the ...
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votes
1answer
71 views

Inverted Deadman Switch (Basic theory, but lost for component ideas.)

Rather than... Intial state current OFF; Foot pressure = current ON. Looking for... Intial state current ON; Foot pressure = current OFF. Looking for ideas on components to modify a foot pedal I ...
3
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4answers
130 views

Help understanding transformer AUX winding

I'm new here and I'm looking for someone to help clarify the AUX winding of a transformer, more specifically in a switched psu. I see schematics where it's being used either as feedback or voltage ...
1
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1answer
49 views

Charging all night and its effect on the charger

I googled about this topic and I found that keeping the charger plugged in the wall for days will consume a very small amount of energy and will not cost too much. And most of smart phones disconnect ...
3
votes
2answers
67 views

Can a “distributed gap” powdered-iron or ferrite toroidal core be used for a flyback converter's coupled inductor?

As just about all of us who deal with switching power supplies know, flyback converter designs use an air-gapped coupled inductor instead of a transformer. Typically, this gap is an explicit gap in ...
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0answers
33 views

Using ZVS circuit as a 12vdc-120vac

I have been playing with this module, Super high voltage. It is very fun, and excited and all, but it has little purpose, so I was thinking about using this module as a 12v-120v inverter, and I found ...
0
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1answer
229 views

SMPS schematic - transformer calculator

I found this schematic for a simple SMPS. I want to use it to build a 24V/2-3A power supply for a soldering station. How are the turns on the transformer calculated? For the primary I can use N = ...
0
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1answer
207 views

SMPS mobile charger design

I have designed a mobile phone charger according to following circuit diagram. Its input is AC220V and gives output DC5V, gives current upto 400mA. fortunately this is working and charging my simple ...
4
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2answers
65 views

Switching regulator efficiency TI LM2678 - measured vs. datasheet

I'm working with a TI LM2678-ADJ regulator (granted, on a breadboard) to power a 40" led strip. Trying to figure out why the measured efficiency is about ~15% lower than what the charts in the ...
0
votes
1answer
41 views

Series Electrolitic Cap life

My country has 230V mains. Many imported SMPS have a 230/115 VAC switch that means that the SMPS cap filter input stage runs like a fullwave bridge here. It means that it runs like a full wave ...
2
votes
2answers
44 views

Can an audio receiver with a 130v-rated switching power supply be modified to be used without a power transformer?

I have a Harman Kardon AVR, imported from the US, which uses an SMPS (130v) that I will use in Asia. Is there a way to modify the component inside the Power supply so that I can use it without a ...
0
votes
2answers
102 views

Generating 5V DC in an AC system without the neutral wire

This is my first foray into AC circuits, I've only worked in low voltage DC circuits before. I am building an AC dimmer circuit with a wireless radio, a bit like this device and I don't quite ...
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votes
1answer
116 views

Schematic of switching power supply 230V to 5 / 3.3 VDC [closed]

I would like to ask you if you have the schematic of the power supply mentioned below. There are various variations but the input is always AC 85-265V 50/60 HZ while the output is, depending on the ...
1
vote
2answers
92 views

How do I slightly change amplitude of the 230 VAC loaded power line?

Let's say there is 230 VAC power line. How can I convert it to let's say 223 VAC? Expected current is up to tens of Amps. I could do one the fllowing: Use 10 bidirectional diodes to convert these 7 ...
1
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4answers
76 views

LT3845 not giving 1.3V

I am using the LT3845 to obtain 1.3V of output. From the formula given for calculating the resistors to obtain 1.3V, I conclude that R5(the one tapping into the Vout) should be approx5.69Ohms and the ...
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votes
1answer
62 views

What kind of transformer was used in this led driver? [closed]

I'm trying to examine the parts of the led bulb that I disassembled. I'm having a hard time distinguishing what kind of transformer is mounted on the circuit. I'm planning to build a driver for my ...
0
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0answers
74 views

Voltage Drop / overheating Power supply

it's my first time on stack exchange . I am a Belgian student in electronics engineer and i work also part time . I am in charge of finding a better way to charge tablets used in restaurants. But I ...
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0answers
36 views

How do “universal” (100-240V) switched mode power supplies work? [duplicate]

There's a plethora of universal AC adapters out there, and I've noticed that most are capable of handling 100-240V/50-60Hz input. I tried to look up some info regarding how the power supply is able to ...
0
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1answer
100 views

Why won't this PC power supply run my BLDC?

I would like to power my Arduino and BLDC to be powered with an old computer power supply. My Arduino needs 5V and my 3 phase BLDC needs 12V. simulate this circuit – Schematic created ...
0
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2answers
56 views

High Frequency Transformer Design and Materials [closed]

I have designed fly-backs and inductors and understand the basics about flux density, saturation and core losses. What I have never been very clear on is design of SMPS transformers. I get the concept ...