A flyback diode is a diode used to eliminate flyback, which is the sudden voltage spike seen across an inductive load when its supply voltage is suddenly reduced or removed. A flyback transformer, also called a line output transformer, is a special type of electrical transformer designed to ...

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Flyback protection for electromagnet

I have an application where I need to automatically swap the polarity of an electromagnet. The question is how to deal with the flyback voltage as the field collapses. Typical diode is polarity ...
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3answers
215 views

Isolated DC/DC flyback/SEPIC

As far as I understand the flyback topology, it can be used in both buck and boost converters. What I am not sure about is: Does it also work for the case where buck-boost is needed, i.e. \$V_{\text{...
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1answer
127 views

Is a flyback diode necessary for a small sg90 servo motor?

I am powering a small sg90 servo motor (see datasheet) directly using a 12V battery and a simple circuit to step down the voltage to the appropriate one for the servo. I noticed the servo has some ...
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1answer
63 views

Choosing the correct flyback diode (if necessary at all)

I came up with this simple circuit to drive a couple of PC fans ON and OFF from a Raspberry Pi's GPIO pin: Probably I need a flyback diode somewhere, but at this point I don't know where and how to ...
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1answer
81 views

Step up SMPS with unrealistic voltage output with a 100W LED COB load

I got some 100W LEDs to make a lamp, realized with a boost converter I could use an old ATX power supply and bingo I'd be fine. It worked at first, until I didn't like the color so I decided to ...
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1answer
48 views

How to check pin outs for FBT

I bought a flyback transformer recently, 5908-05008, CF68A. However, when I try searching online for this model, there seems to be no pin out diagram or any information at all. Most of the FBT I saw ...
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4answers
100 views

Television flyback transformer: does it do 2 tasks ie. horizontal flyback and E.H.T.?

Television EHT transformer is also called Flyback-transformer? E.H.T. (Extra High Tension) generates the cathode ray; ie. acts in same direction of the main pathway of running electrons, i.e. "...
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4answers
647 views

Using a large resistor instead of a flyback diode

In a video lecture a professor is explaining how to prevent an electric arc caused by the switching operation in an RL circuit. Here is the section (at around 18:26) where he explains it: https://...
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1answer
47 views

How can FETs act as flyback diodes

Considering a 3 phase inverter using MOSFETs without body diode or GAN as transistors. How can the FETs safely emulate diodes? I mean I understand the transistors in question must be able to conduct ...
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1answer
69 views

Use Transistor As Mosfet [closed]

I want to make mazilli ZVS Flyback driver based on this tutorial www.instructables.com/id/ZVS-Driver I needed IRFP250 mosfet for making it I cant find it locally.In the schematic picture they said ...
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1answer
85 views

Can I place my inductors in parallel to make a Flyback?

I would like to build a flyback and I've tried simulating my circuit in LTSPICE, in which I coupled a PCH-45X-824 inductor (820µH, 986mA pk) with a 744139 WE-SI inductor (1.124mH, 3A pk). It works ...
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1answer
37 views

Multiple output flyback converter simulation in Advanced Design System

I am trying to simulate with Advanced Design System (ADS) a multiple output (one primary winding, three secondary windings) flyback converter (see the image). But I cannot find a component in ADS ...
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2answers
135 views

How to connect flyback diodes on a h-bridge [closed]

I'm using a SN754410NE h-bridge to drive two DC motors (4.5V each) with Arduino. After testing the circuit and the code, I made a standalone Arduino on a perma-proto breadboard. My problem is that ...
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1answer
59 views

Designing an High Amperage, Low Voltage AC Voltage “Breaker” for Model Train

I’m trying to build a simple circuit that acts as a "voltage breaker" – meaning that if a voltage exceeds a certain threshold, analogous to a (current) circuit breaker it will open a circuit. There ...
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4answers
292 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 "...
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2answers
78 views

Buck converter after 50Hz transformer

I plan on designing a variable power supply (1-50V, isolated), able to provide a power of about 50W. For efficiency's sake, linear regulation is out of the question. The natural thing would be to ...
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2answers
59 views

Dealing with FreeWheel Current

In the schematic below, I would like to know the best way to dissipate the FreeWheel Current in the very shortest time possible. simulate this circuit – Schematic created using CircuitLab
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1answer
40 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 ...
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1answer
48 views

Power supply - Boost voltage over distances

I'm looking for a good power supply design to boost the DC voltage and convert it to AC so it can be transported over a long distances with low loss. I have drawed a example picture: The only thing ...
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1answer
38 views

Working with freewheel Current

Andy aka, rioraxe and Daniel thank you very much for taking the time to respond to my first question. In the schematic below, an A/C voltage is induced in the inductor. The MOSFET is used to control ...
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3answers
137 views

Correct placement of freewheel diode

I have two questions on placement of freewheel diode in a H-Bridge circuit: 1) In reference to the general H-Bridge circuit below, wouldn't it be safer to place the freewheel diodes directly across ...
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2answers
50 views

Flyback across PMDC motor

A PMDC motor M2 is connected to a constant regulated voltage source. To protect the regulator chip from the flyback voltage, a diode has been added. From the same unregulated voltage source another ...
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1answer
54 views

Error amplifier in dc dc converter chip

I am trying to design a dc-dc converter using the UC3844 IC. The working is clear to me. But the datasheet has an application circuit that is a bit confusing for me. The datasheet. The circuit in ...
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1answer
44 views

Flyback transformer selection

I am designing a flyback converter using the PA3855.004NL transformer. Now, the datasheet screenshot is as shown below - . There is a value of 4.33 in the primary of the transformer. Is it the ...
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0answers
51 views

selection of transformer for flyback converter

I am designing a flyback converter. Now, necessary parameters are as stated - Vin(voltage to primary) = 17-32V, Vout(voltage to secondary) = 12V, Iout = 3Amps. Now, based on the above requirements, ...
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2answers
274 views

Direction of winding (clockwise/anticlockwise) in flyback transformers

Here is a circuit of offline switching power supply based on Viper22a IC: In this circuit and many other similar circuits, they denote the starting of a winding by a "dot". However they never ...
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73 views

Calculating flyback diode values

I'm designing a small herb garden automation system as my first hobbyist project in electronics engineering. I'm still very new to this stuff. I have two general questions but am supplying my early ...
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1answer
79 views

Flyback converter

I am designing a flyback converter based on the UC3844 chip. As a starting point, I went through an eval board that is given in the Microsemi website. The schematic of the design is as shown below - ....
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1answer
118 views

Flyback converter for a step-up application (4VDC to 48VDC)

From what I have seen, flybacks are used for step down applications, are step-up applications possible? More specifically, is converting from 4VDC to 48VDC possible using a 1:8 transformer? I'm ...
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2answers
78 views

How signficant is leakage inductance in a flyback converter?

In designing some flyback DC-DC converters (to give us isolation), we have been simulating potential designs in LTSpice, which has gone well. (Isn't LT great at documentation? Pretty much perfect ...
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1answer
96 views

flyback converter transformer selection [closed]

I am trying to design an isolated dc dc converter. Now, my input is approx 20V and I need an output of 7V at the final output. I understand that I need a PWM controller that is approx 100kHz or so. ...
0
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1answer
34 views

Diode preventing coil from latching?

So I've come across a case where an input from a little 5v I/O system will trigger the coil of a reed switch but not it's direct equivalent that has a built in flyback diode and changing the resistors ...
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2answers
178 views

long wire kickback voltage problem

the long wires acts as inductor which shutdown and sometimes damage my microcontroller(IC1), for the AC part ill be implementing an optoiso along with triac and snubber circuit (lemme know if you have ...
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2answers
206 views

Can a “distributed gap” powdered-iron or ferrite toroidal core be used for a flyback converter's coupled inductor?

As just about all of us who deal with switching power supplies know, flyback converter designs use an air-gapped coupled inductor instead of a transformer. Typically, this gap is an explicit gap in ...
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1answer
1k views

SMPS schematic - transformer calculator

I found this schematic for a simple SMPS. I want to use it to build a 24V/2-3A power supply for a soldering station. How are the turns on the transformer calculated? For the primary I can use $$...
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2answers
183 views

Current flow in a simple flyback topology

I'm continuing my learning about flyback converters, and trying to understand the current flow and the magnetic fields involved. For instance when the mosfet is on current will flow through the ...
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3answers
215 views

bi-directional flyback diode for relay spike protection

A flyback diode is used to protect circuits against the reverse voltage generated by removing power from a relay coil. Like this: simulate this circuit – Schematic created using ...
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2answers
115 views

Danger of Saturation of Primary Coil in a Flyback

I was reading a book, "switching power supply design - Abraham Pressman", specifically the section about flyback converters. One part I'm not quite sure I understand is where he says that the ...
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1answer
83 views

is a 555 timer flyback driver lethal?

i have always heard on websites that the 555 timer flyback driver is not lethal. i know that the common ZVS driver is lethal but would the 555 flyback driver be able to deliver a deliver a lethal ...
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1answer
115 views

High Voltage Power Supply Design

I need to charge a 1000uF 400V capacitor bank off of a 7V LiPo battery within roughly 5 seconds, and have the circuit be as small and light weight as possible. With a constant voltage supply and a ...
5
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1answer
1k views

Transformer and IC heating in Viper22a SMPS design

I have designed an SMPS using viper22a IC. This gives an output of 9.8V and on adding a 10 ohm load resistor, voltage drops to 9.6V, thus giving an output of almost 10 watts. Here is the circuit that ...
2
votes
1answer
93 views

Fuse resistor type

I want to build a flyback SMPS based on "TNY274". About the fuse before bridge, I don't know what kind of resistor should I use for correct operation! Metal oxide film or Metal film or Thick and thin ...
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2answers
172 views

Freewheeling Diode in Bidirectional Motor

I want to drive Brushed 12Vdc, 4A motor using two relays to achieve direction control. But what is the best way to connect freewheeling diode to it, I came up with this circuit. Is it the right way ...
3
votes
1answer
184 views

Check for if I've picked the correct flyback and zener diodes for a solenoid valve driver

I want to use an arduino power driver shield which contains the RFP30N06LE MOSFET to drive the 12V version of a solenoid valve which has a power consumption of 2.0 Watts (so 167 mA current draw I ...
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2answers
101 views

why L6565 has input range of 80v-240v? Why not 12v-240v?

L6565 Data sheet specifies that input range starts from 80v to wide range. Why the range does not start from 12v? Is it possible to make it to input from 12v and up?
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3answers
193 views

Flyback Transformer Troubleshooting

We have been trying to figure out for weeks why these flyback transformers keep failing. They are these specific transformers http://www.pca.com/Datasheets/EPC3205G-X-LF.pdf We are running them at ...
0
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1answer
78 views

Question about fly-back diode

I read an article from wikipedia about freewheeling (flyback) diode which is used to drive a relay. I understand it but I have four questions. Would you give me a hand, please ? 1- Why does the coil ...
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3answers
97 views

L6472 step motor driver and flyback diodes

I plan to use the L6472 step motor driver but I'm not sure if I should use flyback diodes connected to the driver output side. The step motor will be bipolar with the following specs: The L6472 has ...
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0answers
116 views

Fly-back converter

I'm trying to get 2 isolated outputs (5V and 3V from 12V DC supply) using a single flyback converter by adding one more secondary winding on the flyback transformer. Following is the Simulink model I'...
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0answers
186 views

Flyback Transformer Active Snubber Design

I'm using a flyback transformer along with the LT3750 controller by Linear to charge a capacitor. I'm wanting to increase efficiency and improve the circuit. I began with looking into an RC snubber to ...