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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123 views

LDO vs switching regulator

We've currently got a PCB that needs to power a modem and a microcontroller. The PCB is powered via a battery (12V - 30V range). The modem and the microcontroller have separate power lines. The ...
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44 views

Oscillation on an 4 phase 12 to 24V 20A boost inverter

Oscillation on an 4 phase 12 to 24V 20A boost inverter I’m using 2 pieces of LTC3787 to make a 12-24V inverter. I made a 4 layer board from it to have enough ground to make sure all will be stabile. ...
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103 views

SMPS gives “electric shock”

I built the following circuit, a reference VIPer22A circuit. It works fine but I have a little problem. It gives an electric shock on the secondary side. It's not a "line" shock (sticking your ...
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59 views

Troubleshooting a power issue on a DIY board

I built a board that combines a number of sensors, an ATmega2560 and a TPS62125. The board worked, I was able to measure 3.3V coming out of the buck regulator, and was able to program the ATtmega via ...
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58 views

What is too noisy for a switching power supply

I built a buck converter to take a ~12V battery source down to 3.3V to power an atmega2560 running at 8MHz. Here's my scope output looking at VCC when it's running (at this point, I'm measuring an ...
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315 views

Why would a switching power supply fail with a battery supply?

I have this power supply circuit I have been using for a couple of years: I have put it on a lot of boards, and ranging input voltages up to 50 volts (as long as the capacitors are rated that ...
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1answer
35 views

Relationship between switching frequency and controller's crossover frequency in buck SMPS

Context: tuning the control loop of a buck SMPS. I specicifally have a TI TPS40200-based circuit in mind, but I think this applies to SMPS design in general. Quoting from Type 2 compensation network: ...
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34 views

How to fix current leakage in a laptop at the mains? [closed]

See this previous question: current leakage in a laptop Kind of reopening this case, I expect that some fix at the power supply side would fix this, like connecting the neutral with the ground, OR ...
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19 views

How to rectify the power line for leakage current based electrical shocks? [duplicate]

In May 2014, I had purchased Samsung LCD TV with two pin mains cord. I used to get electric shock like feeling when I touched the metal body part of it or the HDMI port (any other connected ungrounded ...
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1answer
48 views

Do I need to isolate the output voltage feedback in SMPS?

I almost finish with my Half-Bridge SMPS design. I'm now designing the output voltage feedback to the controller stage. The controller stage drives both MOSFET transistor through an isolation ...
2
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1answer
69 views

Where can I find a stable AC to DC switching power supply?

I've purchased multiple 3V switching power regulators form Amazon and they all have spikes in the ripple. Here's an O-scope capture: The spikes increase frequency depending on the load. Are these ...
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137 views

Inductor selection for a switching regulator

This is somewhat related to this question, but hopefully a bit broader. I'm selecting components to fill out an lm2734. This regulator will take a 9-12V (11.1V nominal) input down to 5v @ 1A max. ...
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1answer
73 views

How to the calculate the value of capacitor placed in series with transformer to avoid flux walking in a buck converter? [closed]

The dc value of current in primary increases(in -ve direction) as time passes, so I need a capacitor in series with transformer, but don't know what value capacitor should I use. filter capacitor = ...
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1answer
70 views

Transistor Level Shifting in Buck-Boost Converter

Ive been reading some of the LT application notes on Jim William's Analog Circuit Design book, and there's something I don't quite understand. I'm attaching a scan of the circuit in question. The ...
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50 views

Weird computer SMPS issue

I am using a off the shelf 550 watt computer tower SMPS to run my 3D printer. It's imperative that this power supply be robust to ensure that my printer doesn't go haywire or turn off mid-print. I ...
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3answers
163 views

DIY current-limited 40A+ power supply to emulate LiPo batteries

I want to do some experiments developing brushless DC motor control hardware, and maybe wiring my own motors for my own edification. LiPo batteries aren't convenient enough, and I want ...
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1answer
61 views

Help Running Xmas Lights On 6V AC Flying Saucer

first time here. First I will explain what I have then ask for a solution to my problem... I have a fiber optic UFO display that has a slow turning electric motor to revolve a color wheel to light ...
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1answer
71 views

Constant Current Square Wave through LED

I am running a somewhat powerful LED, on the order of 3.5V 500mA, off of an ~11V battery using a constant current switched mode power supply from Ebay that uses the LM2596. What I need to do now is ...
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1answer
60 views

How create a low-voltage boost (~4v to 5v)

I am looking for a circuit that will go from a Li battery that has a voltage between 3.6v and 4.3v up to 5v - and I have seen similar questions such as this and this, but those just recommend ...
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1answer
73 views

What is the ideal way to handle data pins D+ and D- on a USB power adapter to be compatible with fast charging on devices?

I have found that many USB wall chargers use a resistive voltage divider to set the D+ and D- pins to a specific voltage, usually between 2 and 3 volts. Other USB wall chargers short the D+ and D- ...
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1answer
73 views

SMPS : Average Current Control Vs Peak Current Control

Please correct my understanding. I understand that in peak current control mode, the slow outer voltage control loop generates a current command to the faster inner current loop. This current command ...
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177 views

Why would the output voltage of a 5V SMPS (USB charger) increase with load?

I've been using a USB voltage/current measurement device to evaluate power consumption of USB devices and performance of USB chargers and batteries. Most of the USB power supplies I've used are ...
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1answer
38 views

Inductances in flyback transformer

I am simulating flyback dc-dc converter in multisim software tool .. I want to know the difference betweem primary inductance and magnetising inductance , also secondary leakage inductance?
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2answers
88 views

Can I power Ardiuno using buck converter IC 3485 or any other buck circuit?

A buck circuit lowers the voltage by generating pulses at a certain duty cycle. Is it okay to give this pulsing voltage to Arduino? Can Arduino work normally with this? I have 12V battery and I want ...
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1answer
97 views

Why is a resistor put before the gate of a transistor?

In most of the H-bridge driver circuits I've come across so far, there's a resistor in the path of the signal to the gate/base of the mosfets/BJTs, like in the images below why is it put there ? ...
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16 views

Noise in Inductor Current : Buck Converter [duplicate]

Source DC: 300v DC Output DC required : 160v DC Load Current : 7A DC Buck Converter Topology : IGBT as switch @ 8khz 1.1 mH Ferrite Core Inductor Measured Inductor Current ...
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213 views

High EMI PCB track under transistor or diode package

Can a high EMI PCB track under a transistor or diode package (in this case TO247AC) be a problem? To get a better understanding: Is there any advantage on putting these tracks on the other side ...
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122 views

Spikes in Inductor Current : Buck Converter

What could be the reason of such spikes in inductor current at each Switch ON-OFF. ?? This spikes are also getting affected in load current. Please help me to reduce / remove this spikes. ( ...
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1answer
203 views

LM3485 current limiter (\$R_{adj}\$) value selection

I have what I believe is a working buck converter design centered around the LM3485. It's intended to be a Raspberry Pi power supply. The schematic is at Pi Power schematic, which I copy below. ...
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2answers
62 views

Using triacs to switch more complex equipment than just motors and lights?

Obviously triacs have been well known to be used in applications which don't really require a perfect sine wave to function. However, what about say a triac to switch on and off more complicated ...
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62 views

Stray-inductance and capacitance of non-isolated heat-sink

I read an application-note that says the heat-sink (when not electrically isolated), is one of major source of EMI. Well I think this can be corrected at some point by good EMI filters and a good case ...
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2answers
73 views

Switching regulator PCB layout

I'm putting together a buck regulator (first time around) based on the lm2374 chip. TI provides gerbers of a recommended layout for this chip family, but my configuration differs a bit. I've read up ...
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234 views

What is a good power electronics textbook?

I really want to learn as much as I can about power electronics, switching mode power supplies, and overall analog design. Unfortunately my universities computer engineering program is still ...
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74 views

What is an auxillary winding in a flyback transformer?

I am researching about SMPS, specifically AC/DC flyback converters. In the datasheet for the switching controller (Fairchild FSCQ0765), it refers to an auxiliary winding. What is that? All the ...
2
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1answer
62 views

Catch diodes in switch mode power

I am wondering about catch diodes in the context of switching power supplies. I have read all the books that are the norm in designing a SMPS, but all of them don't or barely touch the subject. My ...
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1answer
78 views

calculating total power consumption with LDO vs switching regulator

I'm just getting somewhat familiar with voltage regulators and am trying to make sure I'm understanding a bunch of parameters correctly. Scenario: I have a project that spends 1/3 of its time ...
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414 views

Deciding capacitor value to use in my circuit

I have a power source which supplies 1A at 5V. I am using a switching regulator which supplies 1.3A at 3.3V. The load requires a burst of 2A without reducing the voltage across it than 3.2 V for 477 ...
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1answer
95 views

How can I modify the charging circuit of the solar powered system using super-capacitor with or without battery (diagram is attached)?

I 'm working on a device which according to the below diagram, has a solar panel witch gives at most 10v voltage and 30mA current (average 9v and 20mA) and also it has a 6v lead acid dry battery with ...
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32 views

Battery Charge Regulation Application

I'm building a switched mode power supply unit to take electrical energy generated by solar panels and store it inside a Lithium Ion battery pack. Some specifications: 1. The solar panel open circuit ...
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1answer
117 views

Switch mode power supply connected to the diesel generator makes bad voltage oscillation

GEKO diesel generator has 60 kVA electric power. Our switch mode power supply connected to this generator via passive filter DL-50EA3 and 6-pulse bridge rectifier (see the schematic). In this ...
3
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1answer
226 views

Assistance required to design a Powerbank

This is essentially a Q & A tutorial set - as provided for in SE rulez. I am trying to build a Power Bank* on my own. Can anyone assist me in designing a circuit or suggest ones which may form a ...
2
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4answers
394 views

How to make a step down DC-DC converter fail safe?

I'm planning to power some high power colored LEDs with a buck converter, using a microcontroller to control the switching to maintain a constant current. I'm also considering a simpler, switched ...
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1answer
86 views

SMPS input voltage

I find lots of SMPS, with a PWM current mode control IC in the input AC variation range of approx 1:3. From 85V AC ~ 265V AC at its input. Which parameter restricts this is it minimum 'Ton' possible? ...
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110 views

Switched-mode constant current supply with Schmitt Trigger

I'm planning on building a small constant current power supply for charging lithium-ion batteries on the go. While they normally use constant current AND constant voltage, I've elected not to include ...
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3answers
139 views

Power 4.5V Lego motor by 5V PSU, how?

It's a long story. Please bear with me as I try to describe what I intend to accomplish. I've got a Raspberry-PI controlled Lego Technics (pre-Mindstorms era stuff) construction. It uses a couple of ...
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0answers
46 views

How to add a desirable phase shift in the input from 3-phase ac mains?

I want to build a 12 pulse rectifier circuit. I know delta-wye or wye-delta transformers can be used to add phase shifts equal to the multiples of 30, but I don't want to use transformers. Is there ...
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2answers
135 views

Flyback SMPS Transformer choice

In several projects so far, I have been using old "fashioned" transformer based power supplies. However, this time around I want to use a switching mode power supply. The supply will be used to power ...
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2answers
89 views

300W Boost converter design

I am designing a boost converter. I know maybe the specs I want would suit better in another topology like Half-Bridge or Full-Bridge but the boost topology is simpler and inductor winding is simpler ...
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1answer
52 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 ...
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2answers
279 views

Manual transformer winding - dots convention

I've already seen this and this. But I can't decide how to correctly wind a SMPS transformer. This is the transformer: I mantain the same turns direction (CCW if you look at transformer from the ...