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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
255 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 ...
0
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1answer
37 views

Does a DCM flyback always operate in CCM during startup?

In the flyback topology : When dimensioned for fixed frequency discontinuous mode, to me it seems unavoidable that the converter will operate in CCM during startup since v=L*di/dt. And since the ...
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2answers
126 views

Problem in IR2112 use

What is wrong in this connection diagram. I had provided pwm with 20kHz and 5volts. But at the R3 I am not getting results
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1answer
110 views

Dual Power Management with MOS

I am working on a design with 2 12V power supply, one external and one from a battery. The current needed is about 7-8A. I could have use schottky or simple diode to protect one supply from another ...
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0answers
45 views

Is the switching speed of MOSFET comparable to that of a Schottky diode?

Assuming identical voltage and current rating, which is having higher switching speed? MOSFET or Schottky diode? In synchronous buck converter, we replace Schottky diode with MOSFET (low side) for ...
3
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3answers
225 views

Portable 5v power supply to duplicate wall wart

I've got a wifi device that works off of a 5v 2a wall wart. I need to walk around with it to get some signal strength ratings, so I am making it a portable power supply. However, the device won't ...
4
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6answers
2k views

Does output voltage of a boost converter depend on load current in CCM?

In the thread below, there are different opinions whether output voltage of a boost converter operating in continuous conduction mode (CCM) depends on load current or not. Boost Converter Output ...
2
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1answer
61 views

What is the difference between these two half bridge configurations?

I have seen two different half bridge versions. One has an extra capacitor attached between the load and the neutral point of the capacitor divider. What is the difference?
0
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1answer
52 views

SMPS design problem, low available current

I'm having an issue with this SMPS design where the voltage is correct at approx. 19.45V but I'm getting nowhere near the target of 3000mA The zener voltage on D3 is 18V. R3 is a 1K resistor. When I ...
0
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1answer
57 views

Beginner's power supply design

I'm trying to design a bench power supply that can be easily controlled by a microcontroller and is more efficient than a simple linear design (although crazy-high efficiency is not the primary target)...
1
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2answers
131 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 ...
11
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3answers
977 views

Why are boost/buck converters never fully integrated/all-in-one?

Moving from small arduino applications to higher-power applications for work, I've had to switch from using simple linear regulators to switching boost/buck converters any time a different voltage to ...
0
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2answers
132 views

Power Supply for two 50V/12.5A Solenoids

I'm in the planning stages of building a custom pinball table and one of the sticking points is powering the flipper coils. They're 50V DC coils with a resistance of only 4 ohms during the stroke. ...
0
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3answers
204 views

Voltage regulation for Atmega328p

I am designing a circuit containing two Atmega328p. First chip will drive TFT screen with 3.3 V linear voltage reg. Second one will drive BT module, couple of relays, two sensors, SD card module, and ...
0
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0answers
42 views

MIC4830 output voltage too low

I have built the typical applicaiton circuit from the MIC4830 datasheet. I have used the values for 0.4inch2 EL panel running at 900Hz (REL=0.369MOhm, RSW=321kOhm). The input voltage is 3.3V. My ...
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0answers
26 views

Voltage variation and electrical fields Maxwell Equations

I actually know without knowing the reason or the mathematical expression of the physical phenomenon, that if we apply accross a capacitor a voltage which varies in function of the time, it produces ...
1
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1answer
60 views

Is it better to use mains power or an external power supply for a rack mount unit? [closed]

I've seen many rack mount audio units that have an IEC connector for direct mains power, and others that have a DC jack for an external power supply (12V DC for example). What are the advantages and ...
0
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1answer
93 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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2answers
41 views

How does an “auto voltage setting” laptop charger work? [closed]

I recently came across a very interesting device for me, a laptop adapter that claims it adjusts its output voltage automatically: https://www.trust.com/en/product/20194-plug-go-universal-90w-laptop-...
0
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1answer
42 views

MCP1630V a battery charger

To charge a 4 cell Li-Ion battery pack, microchip have developped a circuit (board) that I am trying to understand, (the link for the PDF is here:https://www.microchip.com/developmenttools/...
12
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4answers
4k views

A 1USD 11W led bulb circuit and parts analysis

I know this is not a huge deal, but still I want to do it because for Three reasons: 1, it only costs 1 usd. Yep, this is a very cheap led bulb, and I need to take it apart to see if it's trust worthy....
0
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1answer
158 views

Power supplies with medical safety approval

Regarding the data sheet of this SMPS power supply. In the first page it says: 2 x MOPP Medical safety according to AAMI/ANSI ES 60601-1:2005(R) and IEC/EN 60601-1 3rd edition Then I googled to ...
0
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1answer
221 views

Multiple Voltage Switch Mode Power Supply

Building a multiple voltage power supply for an extremely harsh environment. Will be in a factory type environment with heavy equipment. Looking for a sanity check on the schematic and board and any ...
2
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1answer
130 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 ...
6
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1answer
5k views

Analog & Power Ground Planes Doubts

Working on a new board, I have to face some requirements to ensure the performance of the whole system once is manufactured. PCB is a 4-layer one, and it has both analog and digital components. But ...
0
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0answers
33 views

Making a more efficient replacement for my diode

I am making a boost converter using the LM3481 IC (although it might be considered a sepic topology as well). Typically in a boost topology, you put a diode before the output capacitors so they don't ...
1
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1answer
43 views

Output capacitor current of boost converter

I am simulating a boost converter. The input voltage is 8 V and the duty ratio is 0.3. The load resistor is 1 ohm. I want to plot the output capacitor current. In DTs time when MOSFET is on, the ...
2
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2answers
83 views

Resistor annotated with a frequency

The LT3757 datasheet includes the following schematic: The resistor in the bottom left corner is annotated with a frequency (100kHz). What is the significance of that annotation?
1
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1answer
196 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 ...
0
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0answers
27 views

Line and load regulation testing of flyback converter

I have designed a flyback converter with dual outputs. I have the following queries for performing line & load regulation tests for the same. 1)To perform line regulation on 25 V rail, should I ...
0
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1answer
23 views

Bad Waveform on Output of Buck Converter

I have designed a buck converter (poorly) and have been getting terrible noise. I made a post here where I was given suggestions on how to do a proper layout for my buck converter. This post also ...
0
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2answers
42 views

With a SMPS charging a capacitor bank. What is the power rating of the SMPS?

I'm working on a project to build a 24VDC to 250VDC switch mode power supply for the purpose of charging a capacitor bank. The capacitor bank will be rated at 250V and 180mF. So, the prime power ...
11
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1answer
2k views

Why do some switching regulator require tantalum or electrolytic capacitors instead of ceramic?

I'm looking at this switching regulator: http://www.ti.com/lit/ds/symlink/lm2675.pdf. For its input and output capacitors it recommends tantalum or electrolytic capacitors. It mentions in section 9.2....
0
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2answers
38 views

Low Dropout Regulator Enable Delay

I have a main buck DCDC 5V that feeds to five different LDOs(3.3V). To create power sequencing, I would like to use a resistor and a capacitor at the input of the enable pin of each LDOs and by ...
-1
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0answers
30 views

Designing transformer for uc3842 offline flyback power supply

I need help on how to calculate turns in flyback transformer for the above mentioned power supply. Now I know about designing Half bridge, full bridge and forward converters but I am unable to figure ...
1
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1answer
62 views

Techniques for Filtering a Noisy Buck Converter

I have built a buck converter on the TS30011. Unfortunately, I am getting terrible noise on the output. External Parts Used: Inductor Output Capacitors I have been analyzing my design and have ...
2
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0answers
103 views

Help identifying component in SMPS

I have been working on a Schroff/Cherokee Europe PE1947/23B SMPS (circa 2004?) and have had trouble identifying a component within the circuit. This SMPS features the following outputs: +12v DC @ 8A ...
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0answers
27 views

What's the LC filter arrangement on dual output DC/DC converters?

It's pretty hard to find a filter arrangement for a dual output converter, but I came across the following:- Taken from here. So for the bottom example, is the LC arrangement correct? I always ...
1
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1answer
58 views

Gate driver using switches UC3842 PWM Controller

I have prepared a crude model of boost controller using PSpice simulator of UC3842 IC Gate driver has Ron and Roff as 1 and 100meg respectively (S3 and S5) and Vout will go to external mosfet or a ...
1
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1answer
112 views

Mechanical Switch Causes Transients from AC-DC Power Supply

I'm having trouble getting rid of output transients from this Mean Well PSU right after the AC input is switched. https://www.meanwell.com/Upload/PDF/RPS-500/RPS-500-SPEC.PDF The PSU is a RPS-500 ...
1
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1answer
53 views

SMPS feedback circuit with voltage regulation and current limiting

i’m self learning electronics for a few months now and i choose my first project to be a bench SMPS. Since it is my first circuit design ever i really need some clarification. My SMPS is 2-switch ...
1
vote
1answer
92 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 ...
3
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5answers
3k views

Benchtop power supply current limit on MC34063 switched-mode power supply

I'm currently building a power supply using a MC34063 IC. I have used an external n-channel MOSFET for switching the high current used to drive an LED pair. simulate this circuit – Schematic ...
2
votes
2answers
43 views

SMPS controller duty cycle resolution

when reading the datasheet for some SMPS controllers like the lm25116, I can see that they operates around 1MHz, but nowhere we can find their duty cycle resolution: 8bits, 12bits, 16bits ? So I'm ...
0
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0answers
23 views

Gate Current Calculation and Practical Mosfet Selection

Vnoo3 is the drive voltage, and Ig is the gate current. What I am wondering is: 1) How to calculate the peak Ig on the rising edge of the pulsed gate voltage? For instance, using the spice image ...
2
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3answers
114 views

Energy in transformer air gap

Here is the following assertion : Question: Why is it commonly stated that in a flyback transformer, the "air gap carries most of the stored magnetic energy"? Answer: We can intuitively ...
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0answers
19 views

meanwell psu inrush current and temperature sensor

I want to use a Meanwell PCB mounted power supply on my next project. https://www.meanwell.com/Upload/PDF/IRM-20/IRM-20-SPEC.PDF The spec sheet says that it has an inrush current of 20A/115VAC (I'm ...
8
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4answers
3k views

MC34063A: Why am I overclocking this chip?

I've decided to get some experience with DC-DC converters and I've obtained an Onsemi MC34063A DC-DC converter. From documentation I've got the datasheet, the AN920 application note and the Excel ...
0
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3answers
60 views

Can a single phase SMPS be converted to run from three phase?

If you have a switch-mode power supply that runs off 240 VAC single phase, is it possible to convert it so that it runs off 3P+N (415V phase-to-phase) by only changing the bridge rectifier? I have ...
0
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0answers
58 views

How to prevent voltage droop when discharging a battery?

This is quite an open question, so apologies in advance if you would rather schematics and the like, if you really think this would help I can provide them My problem: boosting from 2x AA Li ...