Tagged Questions

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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51 views

Can I build a high-frequency SMPS choke out of an arbitrary coil of wire?

Suppose I want to build a boost converter that runs at 100 kHz, with an input voltage of 600VDC and an input current of 100 amps. (This is hypothetical, I know the semiconductors involved would be ...
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1answer
36 views

SMPS Inductor oversized vs properly sized

I am working on an SMPS for boosting an input voltage to drive a single string of LED's. The input voltage range is from 18 to 32 volts. The output voltage needs to be about 60V and the drive current ...
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1answer
76 views

SMPS regulator blows up, could it be a layout issue?

I have a curious problem which I have been trying to solve for a few days now and I just can not understand what is going on. I have designed a SMPS which takes 24V input and outputs 5V (which is ...
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1answer
71 views

Switching between two output voltage

I have a sensor which generates signal in range of 240mV to 940mv. Now, I use amplifier of voltage for my sensor, which generates output signal in range 350mV to 1000mV. I used rail-to-rail ...
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32 views

half bridge … transformer and devices overheating

I have made a SMPS for Audio Amp with the following Spec Input Voltage range - 100 - 270VAC Line frequency - 50Hz Output Wattage - 550W Output Voltage - + - 50V @ 5.5A These are very basic ...
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30 views

Why is the output voltage of the forward converter is dependent on the duty cycle?

The Wikipedia article "Foward Converter" claims that the output voltage of the forward converter is $$ V_{out} = D \times \dfrac{N_s}{N_p} \times V_{supply}. $$ Where, \$D\$ is the duty cycle. Here ...
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1answer
41 views

Connecting devices powered by separate SMPS without common ground

I have a power over Ethernet design using the SI3402 PoE PD chip to generate 3.3v for a pic 18F67J60. The switched mode voltage converter in the SI3402 is a little unorthodox in that it switches Vss ...
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1answer
40 views

Switching power supply using faraday cage and EMI protection?

Several switching power supplies in the market use this kind of cages to protect the circuit, however, i have this question, A) Is this used as a faraday cage due to the high frequency used by it? ...
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48 views

SMPS: What is current mode instability (aka “sub-harmonic oscillation”)?

In peak current controlled switching power supplies, there is a phenomenon called “current mode instability” aka “sub-harmonic oscillation”. What is that? Can't seem to get a good explanation of ...
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3answers
179 views

What is the advantage of a switching over a linear power supply?

I want to build my own switching power supply. I already know how to make a 10 Ampere Linear supply, and I'm wondering if I should bother. What do I have to learn to do a switching supply? What makes ...
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2answers
63 views

Info on transformers? Where to find?

I'm quite often taking things apart to salvage the parts and use them in my projects. Right now I'm taking apart an old PC-power supply for a switch-mode lab-supply project. The power-supply in ...
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1answer
60 views

Capacitors vs buck/boost converters

I'm trying to drive high power LEDs with a laptop power supply, and wondered if I should use resistors to limit the extra current, or something like this to limit the current. If I did use that ...
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39 views

Switching Power Supply makes speakers hiss

I have a computer with a 5.1 soundcard, that I'm using to run a standard PC 2.1 setup (Corsair SP2500) on the main audio output, and two rear surround speakers I had laying around. The speakers in ...
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1answer
42 views

Using bench power supply to drive ex-cordless driller

Ok, so I perhaps naively thought I was the first person to ever think of this - go figure. Anyhow I managed to get my hands on a couple of cordless drillers which have an expired battery and thought ...
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1answer
69 views

Simultaneous Buck-Boost or Flyback Regulator - Help Selecting Chip [closed]

I have been trying to find a switching DC power supply that outputs a constant voltage of 12VDC, given a variable input between 4V and 25V. It's to my understanding I'd need a buck-boost converter, ...
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1answer
110 views

Boost regulator: Unexpected output voltage

I just finished setting up an LM2577 as a boost converter, and have run into some unexpected issues. For starters, here is the recommended "typical application circuit": My application circuit is ...
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1answer
70 views

Strategies for powering an ATtiny micro controller and 40W peltier from mains

I'm trying to power an ATtiny1634 at 5VDC and a 50W peltier element at 12VDC. The microcontroller will, amongst other things, turn on the peltier via a 5VDC non-latching relay. I want to use an ...
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1answer
65 views

DIY wifi radio radio NOISE!

I am building a mono, internet enabled, WiFi radio and I have a problem. I am running into what I believe may be a grounding issue. When I turn the system on, I hear all kinds of noise coming from ...
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1answer
64 views

Voltage drop when servo activates

Background This is a follow up to an earlier question I asked - I have an ATmega2560 running a number of sensors and servos. There are two separate SMPSs running off a single 12V battery, one ...
1
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1answer
31 views

Troublshooting noisy smps

I had a working design of a buck switching regulator based on a TPS62125. It worked fine, with minimal (<100mVpp) noise. I made some changes to my design, seemingly unrelated to the switcher. The ...
1
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2answers
222 views

Where can I learn Switched Mode Power Supply Design? [closed]

Recently I've had terrible luck buying those little DC-DC boards from China off of eBay. We've been trying to build projects where we have some sort of wobbly input DC off of a car or solar, ...
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2answers
101 views

Linear regulated supply from noisy input voltage

I have been working to redesign a faulty circuit board. One of the problems I have identified is the power supply on the board. The input voltage is nominally 13.8V DC from an AC switchmode ...
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0answers
58 views

How to create a 120V-175V Variable Frequency Generator

I am dealing with a system that requires me to drive a capacitive load at 120V-175Vrms, AC square/sine wave at two frequencies: 50Hz and 2000 Hz @ Ipeak = 100mA. I am currently trying to find the best ...
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2answers
49 views

LTC3603 Regulator shorted out

Basically the LTC3603 seems to have internally shorted itself. I'm using a auto generated circuit, realised with Eagle CAD. I'm trying to design a high current switching power supply with the ...
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2answers
78 views

Is this Half-Bridge waveform right?

This started with my question here there is no need to read it, I put it here for additional info. I'm trying to drive two MOSFETs in Half-Bridge topology and I finally could get the pulse ...
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0answers
47 views

Best Topology For High Voltage Isolated DC-DC converter (12V to 240v , ~0.2A)

I have been searching for a design that can serve as a basis for a supply as above, with the following design requirements. It seems most designs I can find are for low power (<10W) Flyback ...
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2answers
117 views

Generate 10A for stress testing

How could I, a cheapskate hobbyist, generate large currents around 8–10 Amps to run through a short circuit? That is, the objective is to stress test a very low-resistance circuit going ...
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2answers
85 views

Low noise voltage regulation

I have a circuit which currently runs off of either a 12VDC wall wart adapter, or it falls back to a 9V battery if the wall wart adapter is not connected. My circuit currently uses a chip which ...
1
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1answer
49 views

Flyback converter current flow?

If you look at the flyback converter circuit above, the current only flows in one of the coils at any instant of time. What stops the magnetic field generated by the coil in series with the MOSFET ...
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2answers
86 views

What's wrong with this IR2110 pulse transformer driver?

I'm trying to drive two MOSFETs through a pulse transformer. I'm using the "Power Supply Cookbook – Second Edition" book from Marty Brown. According to the book the formula to calculate the number of ...
0
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1answer
41 views

Battery discharge rates and current limiting

In a project I am building, I have a CVCC to control the current and keep it where I want it. (The circuit would definitely use more current it I didn't use the CVCC.) The problem arises because when ...
3
votes
1answer
111 views

Do AC inverter H bridges ever get driven this way?

There's a google competition going on at the moment called the little box challenge. It's to design a very efficient AC inverter. Basically the inverter is fed a DC voltage of a few hundred volts and ...
4
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1answer
70 views

Critique of SMPS layout

Can you guys provide some feedback on my layout for this TP562200 buck regulator? I'm using it to take a ~12V and drive a servo. The supplied resistor values should provide about 5.1V, which is within ...
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1answer
98 views

SMPS design with BUCK converter [closed]

I want to design the SMPS with the following specifications- 5V DC,5Amax,1Amin 12V DC,5Amax,1Amin using BUCK converter. Vin DC=24V
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1answer
39 views

What does voltage output from an SMPS look like when inductor is saturated?

I've built a buck smps around the LM2734X. This is meant to power servos, running off a 12V battery source. Scoping the +5V line using smaller servos, I see a stable voltage, with a peak to peak of ...
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2answers
74 views

How to Mount Power Supply to PCB

How can this 5V 3W power supply board be mounted and electrically connected to a custom designed PCB? Or will it be better to get this power supply board instead due to the right angled pins ...
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1answer
28 views

best way to adjust/set SMPS comp / compensation parts

I’m having difficulties with settings the right values for the comb / compensation for some SMPS circuits I’m working one. Is there a good way to set them right? To make sure of stable operation in ...
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3answers
95 views

Power supply ringing when servo activates

I'm running a servo from a 12V -> 5V buck regulator. The servo has a stall current of about 500mA and a nominal operating current of about 200mA. Here's a scope reading from when the servo starts ...
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2answers
144 views

How does R5 bias the zener in this SMPS circuit?

In the description for the circuit below from this data sheet for TNY268 off-line SMPS switcher, it says R5 is used to ensure that the Zener diode is biased at its test current and R6 centers ...
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1answer
90 views

How to make a 50V regulator?

How do I regulate the output coming from a 50V transformer? At the filter's output, the transformer has 50*1.4142=70.7 volts. But this voltage of course drops as a load is applied, since the filter ...
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0answers
43 views

Why would a buck regulator continue to draw current when EN was off?

I've got a board with two regulators on it a TPS62125 (to power the whole board) an LM2734 (to power servos) For the purpose of this test, the EN pin of the LM2734 is pulled down to ground with a ...
0
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0answers
42 views

What controller for a 400W AC-DC SMPS?

I would like to build a big AC-DC SMPS. I built a little one based on ST's VIPer22A. This is a nice little IC that can give up to a couple watts (my design was 5V 1A). It was easy enough to design ...
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2answers
179 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 ...
1
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1answer
56 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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3answers
138 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 ...
3
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2answers
62 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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0answers
65 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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3answers
333 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 ...
0
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1answer
58 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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0answers
48 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 ...