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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37 views

LM7805 drops input voltage of SMPS

I just finished simple digital ADSR for my modular synth. EXT 5v Gate ->1k->digital pin (with 100k pulldown) of ATTINY85->pwm out->LOW PASS->OUT. ATTINY is powered from LM78L05. Problem is, that if ...
2
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0answers
26 views

Switch utilization in dc-dc converters

In the book, Power Electronics, by Need Mohan at the end of chapter 7, it is this image: Relating the output power and the power that the transistor is handling, I want to reproduce this plot for ...
2
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2answers
38 views

LC circuit of buck converter in nRF8001 datasheet

In the datasheet of the nRF8001, they specify in the reference schematic (page 51) the LC circuit to use with the integrated DC/DC converter (see below). Why is there a small inductor L5 in series ...
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0answers
54 views

High-current (20A) low-voltage (~4V) power supply question

I recently kicked my smoking habit with the help of an e-cigarette, or (shudder) "vape" as the cool kids call it. I've grown weary of constantly recharging batteries, so I thought I would build a ...
0
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3answers
47 views

TPS54231 input voltage sensitivity quite high?

I've spent this evening blowing up TPS54231s. Even a couple of TPS54331s. (note that C31 is currently DNP) The input voltage is specified as 17-24 VDC, and this circuit's worked admirably well at ...
5
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4answers
203 views

What is a flyback?

Trying to find this answer is so difficult that I can't even tell whether What is the difference between a transformer and a coupled inductor? is asking the same thing. Some reading suggests that a ...
0
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1answer
43 views

ZVS Driver design and initialization

I'm fascinated by zero voltage switching (ZVS) drivers. So I've been playing with simulations of them in Falstad. Two things I don't understand: How is the oscillation initiated in an actual ZVS? ...
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0answers
44 views

A question about SMPS transformers

The circuit above illustrates an SMPS power supply. The SMSP transformer primer is fed by a chopped DC which is a high frequency varying voltage. I marked this primer part Vprim in red as you can ...
1
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0answers
31 views

Constant power supply with high-voltage “restrike”

I'm still playing with electrolytic chemical reactors. After looking at the results from a constant-current circuit I'm realizing that what I really need is a constant power supply because, depending ...
0
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1answer
48 views

DC fan current requirements

Very basic question here that I thought I knew the answer to until last night, but now I am very confused. I picked up some 12v DC squirrel cage fans for a chassis I am building. Here is the Mouser ...
0
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3answers
76 views

Switch mode PSU minimum load

Alright, I know I am going to get a lot of flak for this, but let me reassure you that I have already spent the last few days reading on Google while going back and forth from the bench to test ...
0
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0answers
27 views

Switching power supply [duplicate]

I am currently working on a project of electronic being powered by DC power (7-40V) from car. The device is supposed to run properly (with several load of total 3-4A at 3.3V) when the car is turned on ...
0
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0answers
26 views

+24v to -24v/200mA Through hole inverter [closed]

I need a through hole switching inverter, which converts +24V DC to -24V DC and can provide 200mA of output current at least, all inverters that I found are a surface-mounting type and I need a ...
-3
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0answers
55 views

PCB layout of SMPS module [closed]

We are using a SMPS module with the following specifications [input] 240Vac [output] 12V @ 0.7A Enclosed Attached is the bottom view of Module as per datasheet. Pin 5 is Line Pin 6 in Neutrul ...
3
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7answers
378 views

Role of Electrolytic Capacitors and whether they can be replaced by Film capacitors in battery operated power converters

In battery operated power converters such as motor controller ( half bridge or full bridge ) bulk capacitance is placed across Vdd and Gnd . I thought this was unnecessary since the input is DC and ...
1
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1answer
63 views

How to choose MLCC cap values for power supply decoupling?

I've read that it's best to use several MLCC caps with different values to filter out as much the varied frequency noise as possible. On the output of the voltage regulator, I see some noise in the ...
-1
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1answer
31 views

Specifications for a flyback transformer

I'm building an SMPS that takes in 110/220V AC and outputs +/- 3.3V DC. The chosen topology is flyback and as is the case of flyback transformers, I need to get one custom made. I have the Np:Ns and ...
0
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0answers
40 views

Oscilloscope builds charge on ground even when it is connected to mains ground

I have a following situation - my scope (UT4102C if that matters) builds some charge (quite painful to touch) on its ground (BNC connectors outer hull) even when it is connected via proper IEC cable ...
0
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0answers
50 views

Buck converter control

I'm using a buck converter to power a resistive load, the requeriment I've is to increase the current progressively, to do this I'm using a uC. Converter specifications are: Input voltage: 28V ...
4
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3answers
109 views

SIM900 Conducted Emissions Fail

I'm currently having trouble getting a product through EMC. Radiated emissions were comfortably under the limit, but conducted are failing badly. Here are the results: The noise appears to be ...
0
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2answers
46 views

SMPS voltage ripple

I'm using the MC34063 for my 35 VDC -> 4VDC SMPS. Here is the circuit (modelled in LTSpice): Edit: However, using a MC34063 calculator and setting Ipeak = 0.5A, L1 = 37 uH C3 = 12.5 uF Which, ...
3
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2answers
96 views

What R, C values to use in an RC Snubber to reduce output ringing in switching regulator?

I am using a simple buck switching converter (AP3211) to convert 5V-12V to 3.3V. The issue I am trying to resolve is the output ringing. I see a 800mV P-P ringing on the output, with a frequency of ...
0
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0answers
26 views

What are the risk of overload a inductor in buck converter?

I've a buck converter working at 100kHz simulate this circuit – Schematic created using CircuitLab So far I have tested the circuit for a 4A output current, but I may need to work with ...
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2answers
69 views

Can i connect a dc power supply rated 20v,6 A to a system which needs a power supply of 8-32v and 1.5A? [duplicate]

Can i connect a dc power supply rated 20v,6 A to a system which needs a power supply of 8-32v and 1.5A? My concern is about current. Will my system only consume max of 1.5A from supply instead of 6A? ...
3
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2answers
121 views

How to keep a 9 volt micro-controller ON when where is no electricity for some minutes?

I want to keep an DCcduino clone of arduino uno ON where there is no electricity for 5-10 minutes with a 9 volt battery. Is there any way to do it without ups because it costs too much?
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2answers
160 views

Is my 600W boost broken or malfunctioning?

I'm asking this mainly as a sanity check and to distinguish between whether I've just done something wrong or need to buy a new one. I have a "600W" boost converter based on the UC3842A SMPS w/ CC ...
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1answer
27 views

Wiring a eTopxizu 12v 30a Dc Switching Power Supply to USA 240 volt plug?

I have a eTopxizu 12v 30a DC Universal Regulated Switching Power Supply. The power inputs are marked Ground-Neutral-Load. It has a switch on the side that adjusts it from 110 volts to 220. When I ...
0
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0answers
25 views

switching power supply causes DC motor to bounce

I am attempting to operate a 24 volt 6 amp average current DC gear motor with a Mean Well DRP-480-24 switching regulator power supply. When I connect it to a motor driver the output cannot operate ...
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0answers
68 views

Identify ic from 24v smps

Pls help me identify the ic used in a 24v smps. It has marking IFA=W03, 6 pin DIP, plastic package.
0
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1answer
25 views

Where can I get knowledge on transient mode boost converter for SMPS?

I am working on boost converters for switching mode power supply . How can I get knowledge on transient mode boost converter ? As I know there are different topologies named CCM , DCM and TM which ...
1
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5answers
96 views

Switching power supply only works when warm

Update With the multimeter and a steady hand, I've found the 3843B PWM controller Vcc pin is 12V when the supply is on, and 8.2V when it is plugged in but cold. Datasheet says it needs 8.4V Vcc to ...
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1answer
55 views

Voltage spikes with ZVS full bridge

I am designing a DC/DC converter. I chose the fullbridge topology. The requirements are as follows: Vin = 75 - 125 Vdc Vout = 200V P = 600W Fs = 100 Khz The basic schematic is as follows: I use ...
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0answers
41 views

Function Transfert Closed Loop PI regulation

i have a transfer function and i need to calculate the PI coefficient in closed Loop Transfer function H(s) = -3.766/(1+ 3.766*10^-3 s) PI transfer function ...
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1answer
59 views

SMPS buck convrter with PWM controller circuit

Hi there I am designing a buck converter run on PWM circuitry for a uni project to drive a MOSFET switch and keep my output voltage constant. The specs are: input voltage of 20v DC +/- 4 output ...
0
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3answers
78 views

N-Mosfet switch circuit strange behavior laboratory power supply

I'm dealing with an N-Mosfet switch circuit to control, through PWM, the temperature of a heater resistor. The mosfet is a IRFS7430-7PPBF. The load is driven at 12V and has a power rating of 80W. ...
0
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1answer
50 views

Inductor's self-resonant frequency: Do we want it to be high or low?

Inductor selection always confuses me. There is a spec for inductors as self-resonant frequency. For example, on digikey, as SR frequency of inductors increase, the price may increase or decrease. But ...
0
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2answers
69 views

Grounding dc project to clean RF noise

I'm doing a home automation arduino / RFID project and using a 12v DC switch mode power supply to power it. This supply will be plugged in to a wall outlet. The project however will have some ...
0
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0answers
23 views

What's the peak voltage of the sawtooth generated by the ic SG3525 or UC3525? Does it depend on the Ct capacitor?

P.S. I need this information in order to make a closed-loop FlyBack CC-CC converter. The Tm transfer function is related to the sawtooth peak voltage: Thanks!
0
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0answers
26 views

Decreasing Voltage of Power Supply Laptop Charger to Solve Another Issue: RIght or Wrong?

I have recently bought a laptop universal charger, and as soon as I plugged it in, the mousepad of the laptop started lagging. The Power Supply Charger is registered as 70W. The laptop requires 65W. ...
1
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1answer
83 views

How come SMPS regulators doesn't show current limiting circuit?

for example the LM2678-ADJ is a famous buck converter, there are also many others. I have googled and looked through other regulators, there are many schematics in the datasheets of how you make the ...
-1
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0answers
28 views

Can I put two identical switch-mode power supplies in series to use a higher input voltage?

I have two identical switch-mode power supplies that are rated for a maximum input voltage of approximately 22V. I have a 36V battery that I want to power these from. I was wondering that if I put ...
0
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0answers
25 views

LNK304 noise comes when using it's output

I've built a power converter with LNK304 for 230VAC to 5VDC. The schematic I've used is in the datasheet: http://www.mouser.com/ds/2/328/lnk302_304-306-179954.pdf at page 4, figure 5. First of all, ...
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2answers
80 views

Can a SMPS LED driver glow 6 Watt LED bulb and same Driver is able to glow 0.5 Watt LED?

LED : 150mA * 3.3v =0.5 Watt 6 Watt LED (0.5 Watt* 12) : Which one is best method to arrange LEDs Parallel or Series. At a time only one LED will glow, Either 6 watt LED or 0.5 Watt LED. ...
1
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2answers
90 views

Reduce noise in Buck converter:

I'm making a buck converter, this is the circuit I've: The average voltage at the output is ok, but I'm getting lot of noise at all nodes of the circuit: I'm using as a main source a 30V 5A bench ...
0
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1answer
63 views

How does an SMPS initialize?

This may sound a nonsense question for some of you but I was trying to visualize how an SMPS initializes. Below is a block-diagram taken from a particular SMPS datasheet: ...
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4answers
176 views

How is galvanic isolation established in an SMPS?

I can understand how an isolation transformer can establish isolation; but since SOME SMPS supplies dont have transformers and they have rectifiers instead; I wonder how the AC and DC ends are ...
23
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1answer
981 views

Unusual chemical reaction on PCB (SMPS circuit)

I have a PCB with smps circuit on it 220V to 5V (using Viper22a). Here is the schematic: And here is the board layout: In the yellow circle region, I am seeing some sort of white deposition in a ...
0
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0answers
31 views

Firing of mosfets

I am designing a converter topology for that i need to mosfets.The switching frequency is 200KHz. Both the mosfets need to be fired one without a delay and other with a delay of 0.2 micro seconds. The ...
0
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1answer
28 views

Limit the current of a fixed voltage via MOSFET+PWM

I have a SMPS which I would like to current limit. The current limiter should have a negligible voltage drop when not limiting (say, <0.5%). I thought of inserting a MOSFET and a hall-effect ...
0
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2answers
65 views

How to control output voltage on a Buck Converter

I'm fairly new to electronics and I have copied the Buck Converter (LM2678) in the picture attached to convert 24V to 5V. After trying it I have actually converted 24V to 9V and my question is if I ...