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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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5answers
181 views

Spec says 7-24V, can I use 25V?

I'm building an IoT device with a Wemos D1 Mini. It should control a relay, and also measure the temperature. The thing is, my only practical power source comes from my garage door opener which I ...
2
votes
1answer
132 views

What could cause my boost converter to output below its nominal voltage?

I'm very new to electronics and I'm building things and experimenting as a learning opportunity. I've put together a boost converter circuit and it works OK, but I've noticed that under larger loads ...
0
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1answer
33 views

SMPS Transformer - Different Current Densities for Primary and Secondary

I've seen a design sheet of an isolated off-line 5V/2A flyback converter. In the "Calculating Wire Sizes" step the designer uses 4A/mm2 for primary and 10A/mm2 for secondary. This seems quite ...
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0answers
183 views

Make a constant current source using a 700VDC supply at 4A

Goal: Charging a capacitor to 700V I want to charge a capacitor(any value) to 700V using an SMPS (buck converter.) to prevend inrush current. It's important that the system could charge the ...
1
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1answer
150 views

Boost converter drawing too much current

I am trying to play around with some SMPS boost converters, in order to power my Nixie tubes at around 170V (boosting from 20V to 170V). Yes, I know that there are already existing power supplies that ...
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0answers
45 views

Slope of the Inductor current

this forum is very helpful in the term of power-electronics. I got a question about LT-spice simulation. I want to compare the slope of the inductor current in two circuits.The only difference between ...
-2
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1answer
69 views

Cordless dremel hard wire [closed]

4.8 v cordless dremel. I've got a bunch of different supplies laying around all different volts none exactly right what would be most comparable battery = 4.8v-.7Ah. Supplies I have close maybe ...
0
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3answers
113 views

Inductance value of an Isolation Transformer

There is a small isolation transformer 'L1' of 1:1 ratio as shown in the image. A 0-24V, 75kHz square wave is applied from push-pull mosfets stage at the 'V_SW' input of the circuit. I want to find ...
2
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3answers
226 views

32.768kHz crystal making audible noise

I am doing a project to record and log the voltages of an 8 cell lithium battery. The project is based on an STM32 microcontroller, and logging is done on an SD card. I have made the first version of ...
0
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0answers
67 views

High side N-channel Mosfet Switching output port short circuit protection

I have designed High side plus low side isolated combined N-channel switching using mosfets for high power switching through Mosfet. The power handling of the design is 24v/70Amp. The design is ...
0
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1answer
246 views

Decoding circuit with transformer topology

I am studying a circuit used for mobile adaptor, where AC to DC conversion is done through bridge rectifier ABS210. Transformer is used for isolation along with IC LP3783 (Offline PSR Driver) and ...
4
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1answer
386 views

Feedback in LM2574

I wonder what is the purpose of 'R66' at the feedback terminal of LM2574? I have seen its datasheet but I cannot find info about this. Instead of a single resistor there is a voltage divider shown in ...
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0answers
38 views

Which power source/elements are better for a spot welder?

I'm going to build a spot welder for the batteries of my RC models, but started thinking which power source is the better choise: 12V car battery with higher start current (500A+) Transformer which ...
9
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2answers
1k views

What's the goal of diode and resistor in parallel on SMPS?

While reading schematics diagrams from several switch mode power supplies of LCD TVs, I noticed that the pin which delivers the PWM pulse to the gate of a MOSFET has a diode and resistor in parallel. ...
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0answers
23 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 ...
0
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1answer
178 views

Why does duty cycle seem relevant when calculating inductor current in boost converter circuit?

I've been working hard to understand boost converters and the role of inductors in the boost converter circuit. I found a pretty good list of basic calculations from Texas Instruments and I started ...
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1answer
87 views

How do inductor specifications impact their effectiveness in a boost converter circuit?

I've been trying to understand how to select an adequate inductor for a boost converter circuit. I'm a hobbyist so I'm not always sure what to look for, so I haven't been able to find something that ...
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2answers
54 views

Recommendations for 24V to 5V AC/DC converter [closed]

I'm working on an ESP8266 thermostat that should be powered by the 24V AC from the furnace. I'm looking for a converter to 5V DC that would be small enough to fit in a smaller enclosure and not ...
0
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1answer
63 views

different types of smps [closed]

I need a 12v 5A power supply for a heating element. I found out there are two main types of smps: first one is mounted in a metallic case and usually cooled by fan (in some websites it is called "...
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0answers
559 views

sg3525/ir2110 feedback problem

i use this schematic to build a half bridge power supply. but i have some problems and need some helps. the first problem is feedback.i think this feedback is not good beacause with this feedback ...
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1answer
111 views

Linear power supply vs SMPS (losses in transformer)

We know that, in a power supply, there are always losses taking place. If we have a linear power supply, the major source of loss is the core loss in the transformer. But in an SMPS, where we have a ...
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3answers
190 views

Is ripple of LC filter constant?

How LC filter ripple becomes independent of load. Does it remain constant or it varies with the load? I know that capacitor filter has low ripple in low load, and with high load its ripple increases ...
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0answers
19 views

Do I consider a downstream devices input capacitance when choosing the output capacitor for a switching regulator?

I am designing a circuit in which I chain together a few switching regulators. Each regulator defines specifications for capacitors to be placed on the input and the output. Do I need to consider ...
2
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1answer
133 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
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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 ...
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1answer
152 views

How does a non-isolated SMPS work?

My understanding is as follows: For an isolated SMPS, we first rectify the input ac voltage, then convert it to a square pulse using a switching regulator. It is then stepped down using a transformer,...
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1answer
79 views

How can I isolate the output of a SMPS

What options do I have for isolating the input and output of a switch-mode power supply? I think one method could be to use a transformer. I have read that many SMPS designs use a high-frequency ...
0
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1answer
97 views

Two PWM signals from TL494

I need to generate two open-loop PWM signals with different duty cycles for my converter. The frequency is 20kHz. I did generate one signal. Should I use another TL494 and connect it to the same ...
1
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1answer
235 views

SMPS Error Amplifier Behavior

In case of switch mode power supplies, we uselly use "Error Amplifiers" (Type 1,2 & 3), my question is: The output voltage of this amplifier (Verr), is it the DC error of the Vref and Vout (i.e: ...
0
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1answer
54 views

selection of power supply ( Linear power supply vs SMPS)

we know that, depending on the specification of our system, we design our power supply, which may be either a Linear Power Supply, or an SMPS. But, if there are no constraints of size, efficiency, ...
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1answer
81 views

smps block diagram and working for isolated topology

I have seen in most of the block diagrams of SMPS of isolated topologies, that the input AC voltage is first rectified and filtered to DC voltage. Then, it is passed through a high frequency switch to ...
1
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2answers
103 views

Do Battery Powered devices require bulk cap at power input?

I am in the process of designing a +5V power supply for a hand-held 2xAAA powered device. When using TI's webench simulator tool to simulate a switcher power supply that I am considering, I noticed ...
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1answer
94 views

Crossover frequency and resonant frequency

Physically speaking, what is the difference between crossover frequency and resonant frequency? As far as I know, the resonant frequency is the frequency at which the system oscillates. And the ...
0
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1answer
80 views

Properly Grounding Analog/mixed ICs from DC-DC Converter

I am making a PCB with an Array of current DACs, which need ~15V, so I'm using a boost converter followed by an LDO. I've (tried my best) to layout the dc/dc & LDO per best practices but I'm ...
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0answers
120 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 ...
0
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0answers
42 views

SMPS topology for combination of current controlled rail and fixed voltage rail

I'm looking at designing a LED driving power supply that can interface with a universal AC main input (~90VAC-260VAC) and produce 2 rails at the output; one a current controlled rail, and the other a ...
0
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0answers
67 views

OKI-78SR-5/1.5 inductor

I want to use OKI-78SR-5/1.5 but in datasheet https://power.murata.com/data/power/oki-78sr.pdf on page 19 I found Cbus and Lbus value that make me confused a little bit. I think that values only ...
0
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1answer
130 views

Can I use a 12V switching power supply to power a G4 LED bulb?

I'm trying to convert a broken halogen lamp to LED using a commonly available G4 bulb. I have a lot of orphaned universal power supplies from various electronic accessories. Can I use a 100-240V => ...
0
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1answer
134 views

Switched mode Battery Charger CC/CV operation

Shown below is the internal block diagram of a switched mode battery charger IC (LT1510). The LT1510 is a current mode, PWM (pulse-width modulated), positive buck switcher that operates in one of two ...
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0answers
44 views

Subharmonics frequency Vs Switching frequency

In current mode control of switching power supplies, it says that the subharmonics instability equals 1/2 of the switching frequency Ws, Can you please explain this fact?
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1answer
41 views

led SMPS converter

Which type of converter is best for an LED light for getting better efficiency and high colour rendering index? We want to design a converter up to 80 Watts which gives indirect lighting and less ...
0
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1answer
90 views

Can I use a DC-DC step-up module for a small form factor computer? [closed]

I want to design a DC power supply for my Intel NUC small form factor PC using a battery. The data-sheet for the PC: ...
2
votes
2answers
43 views

LMR33630A, my built circuit doesn't match the expected output

Using TI's "power designer", I've taken their 33630A and designed it for a 5v output. My actual circuit has a slightly different value for the divider to raise the voltage up to about 5.2v, otherwise ...
0
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1answer
147 views

12 Volt DC Power Supply set up

Can I connect a 12 volt DC regulated switch mode power supply (good voltage control) in parallel with a 12 volt DC car battery (great amp supply) to supply the extra current need to run my RF-...
15
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3answers
416 views

Maximal operational pressure of tantalum and electrolytic capacitors

I need to design a device that have to operate in an high pressure environment (Nitrogen gas). The operational pressure may vary from 1bar (atmospheric) up to 20..30bar gauge pressure. The regular ...
1
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0answers
189 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 ...
2
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0answers
69 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 ...
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1answer
117 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 ...
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0answers
88 views

AC voltage at the output of SMPS

We have 230 VAC power supply in our lab.A chemical earthing is done for this power supply. I have connected a SMPS (LRS-35-12) to it. The Output of SMPS is connected to a load of maximum 2A. I have ...
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0answers
22 views

Designing an inverter with its DC volt and gnd connectors as multi-pins along the PCB, how do i lay out my decoupling capacitors?

Should I distribute multiple decoupling capacitors along the connector rails? Or Should I have a few large capacitors centralised? Is there a mathematical way to evaluate this? Any other methods ...