Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [flyback]

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 generate high voltage sawtooth signals at a relatively high frequency.

4
votes
2answers
424 views

High Step-up Ratio DC-DC Convert (12V-to-150V) - Boost, Flyback, Coupled-inductor Boost?

I am trying to design an on board DC DC converter that generates 150V from a 12V input. I'd like to design it to handle at least a 30-50mA load, but in reality the load will most likely be smaller. ...
0
votes
2answers
196 views

Measure DC component in AC+DC mixed signal in flyback configuration with LTC3108

I wonder how can read Input DC voltage After voltage dropped resistance(R1) That's because this is Self-Ocillation Flyback converter, In here, you can see the VIn is Ac voltage, But I need to know Dc ...
0
votes
2answers
36 views

One single fly-back diode or individual diodes for multiple relays?

Please see my crude drawing: My question is this. If I was to have multiple relays powered from the same rail, but have each one sinking via whatever to respective MCU pins, could I use option B as ...
0
votes
1answer
164 views

Driving a flyback with pure AC sine wave

I am quite confused about flyback drivers. I have a high frequency (up to 50 kHz) AC sine wave generator, and I would like to use it to generate some arcs on a flyback. So I thought I could just wind ...
0
votes
1answer
101 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
votes
0answers
32 views

Understanding flyback transformer datasheet

Please see the below image of a flyback transformer I found. I see voltage/current outputs at each secondary winding. My question however is, how are these determined? I thought the output levels are ...
0
votes
2answers
578 views

Extremely high current in super simple SMPS Flyback

I'm building an SMPS in flyback topology. In order to do it, I use UC3845CB IC. In first step, I wanted to see if it even works at all with pulse transformer that I bought, made especially for flyback ...
0
votes
1answer
478 views

Half bridge DC-DC converter circuit analysis

I was trying to learn how the flyback and half bridge DC-DC converter is working. For Flyback circuit, Understood output waveform is as follows. Keeping this understanding in mind, I was trying to ...
0
votes
1answer
311 views

Simulating Pulse Induction Driving Circuit in Proteus Errors

I've been trying to simulate a pulse induction driving circuit in Proteus to no avail. One issues appears to be with how I am using Proteus and the other seems to be a simulation or setup error that I ...
2
votes
2answers
724 views

Transformer maximum voltage rating specifications

I don't know how to interpret the voltage values found in datasheets for transformers. For example, in the datasheet below: where it says 15v, 50mA near the winding schematic. Is this a maximum or a ...
0
votes
1answer
345 views

Flashing LED circuit using Flyback Topology Flickering Problems

Background: Design an LED circuit that alternatively flashes 40W LED strings approximately 45 times per minute. Approach: I began by getting my hands on Linear Technology's LT3799-1 - Offline ...
0
votes
2answers
35 views

P-Channel MOSFET reverse polarity protection on NMOS array chip

I'm trying to achieve reverse polarity protection for the TPL7404LADR chip which is basically an updated version of the ULN2003 darling transistor array. To do this I want to use a P Channel MOSFET ...
1
vote
1answer
21 views

power supply management IC switching transistor - flyback converter

I have a very simple question : is it better to have the switch (transistor) of the flyback converter, Inside the power supply management IC or outside it? or it depend on the application? Thank you ...
0
votes
0answers
54 views

Flyback Converter Switching MOSFET Breakdown

I am using a UC1845A to control the switching element MOSFET (FCB20N60F) which is used for a typical Flyback Converter circuit. MOSFET's drain is connected to transformer. Rarely MOSFET is not working ...
5
votes
0answers
203 views

Mazzilli flyback driver mosfets keep failing

I've been trying to build a high voltage generator consisting of a high-voltage transformer and a Cockroft-Walton multiplier. I have actually tried several different drivers to drive a high-voltage ...
0
votes
1answer
50 views

Digital DC DC Converter for Power Control

I want to find a way to control a power device from a microcontroller. I must control a power device from the microcontroller, making the voltage to vary betwen 0 and 28 VDC, knowing that the power ...
0
votes
1answer
56 views

Topology choice for wide-output-voltage-range SMPS

I'm intending on building a off line (230VAC), 50W, isolated, constant-current switch mode power supply. This by itself is not a big challenge with the plethora of application notes and examples ...
1
vote
0answers
32 views

Increasing output current from ZVS driver

I bought the ZVS driver as shown in the picture below: After connecting a flyback transformer, I tried measuring the voltage and current at the output. The open circuit voltage is about 12KV. To ...
0
votes
1answer
105 views

Flyback converter primary and secondary sides power calculation

The problem is as below. Input DC voltage is at 12V, transformer inductances are: Lp = 60uH, Ls = 240uH, switching behaviour is controlled by a single NMOS with switching frequency at 60kHz. For ...
22
votes
7answers
34k views

Correct use of Flyback or Snubber diode across Motor or Transistor?

From seeing a few schematics where the flyback or snubber diode has been placed across the transistor C-E terminals (Right Configuration), instead of what I typically seen as the the flyback being ...
2
votes
2answers
1k views

What is the use of the capacitor in this relay circuit?

In the schematic below there is a relay coil driven by a 24V DC battery. In parallel to the coil there is a flyback diode and also a ceramic capacitor. What is the purpose of the capacitor in this ...
1
vote
1answer
93 views

Why would Discontinuous Conduction Mode be desirable for an LED driver?

I saw this press release where DCM was listed as a feature for a new Infineon driver chip. Source: led-professional.com I'm involved in LED driver design for Horticulture where DCM is undesirable....
0
votes
2answers
95 views

Is a current transformer appropriate for a voltage step up flyback converter?

I am designing a flyback converter, input 170V output 1200V at 2mA. I am having trouble finding an appropriate transformer, most do not have a high enough N. Current transformers seem to have ranges ...
1
vote
1answer
62 views

Sizing Flyback Diode

I'm working on a project to run a 12 volt 12 amp DC gearmotor via PWM output from a controller. I am using a Crydom solid state relay to power and motor and trying to figure out what diode is correct ...
1
vote
1answer
209 views

What could be causing ZVS imbalance?

I am using a ZVS driver to test some properties of induction and power transfer. I have never PREVIOUSLY had a problem with MOSFET heating in my designs. Today I changed one coil for another larger ...
3
votes
1answer
68 views

TV flyback transformer replacement without RC snubber?

I need to replace the flyback transformer on my Atari SC1224 CRT monitor. The flyback I removed from this monitor has a model number of Kf4825G, and has an RC snubber attached to it, which does not ...
0
votes
2answers
158 views

Flyback simulation - not regulating at lower load

So I've been trying to simulate a flyback converter with the full load condition of 10v, 10A (100W) at the output at fs = 80kHz. The design equations I used were from "Pulse-Width Modulated DC-DC ...
0
votes
1answer
105 views

Maximum voltage and current input of this circuit?

I am looking to assemble a power supply with an output of roughly 600 watts. One of the components required for such an apparatus is a 40 kVDC, 20 mA flyback transformer that I managed to find and ...
0
votes
0answers
30 views

Flyback, primary inductance selection for wide output current changes

I would build my first flyback converter. Converter would be designed for 2A max and load device would draw about 100-200mA for most of the time with 1.8A peaks. Peaks would take a little longer so I ...
2
votes
2answers
64 views

Coupled inductor/pulse transformer for very tiny power supply

I need an isolated 24V 3mA supply to activate some optocoupler that will be read by some microcontroller. Its power supply will be the microcontroller's 5V. My first instinct was to use a flyback ...
0
votes
1answer
33 views

SMPS Transformer - Different Current Densities for Primary and Secondary

I've seen a design sheet of an isolated off-line 5V/2A flyback converter. In the "Calculating Wire Sizes" step the designer uses 4A/mm2 for primary and 10A/mm2 for secondary. This seems quite ...
0
votes
1answer
110 views

Designing flyback converter - multiple isolated outputs

Can I treat 2 secondary coils with dual voltage output as one with double voltage for the purpose of calculations? This seems to be OK for all formulas based on output power as technically the ...
0
votes
1answer
48 views

What is the purpose of a schottky/zener couple on an isolated flyback topology?

This isolated flyback topology has been generated by TI's webench. It's a classic schematics with a feedback going through an optoisolator. There are, however, two diodes connecting the switching ...
1
vote
2answers
108 views

Advice on choosing components for a flyback arrangement, for switching inductive loads fast

I have a bank of x6 MOSFETs (SUG90090E) connected in parallel, which I am using to switch a current of maximum 30A through a coil (resistance 1R and inductance 1mH), and am looking for some general ...
0
votes
1answer
129 views

Sizing zener and resistor for solenoid flyback

I am trying to drive a vibratory pump from a 220 V boost converter (the common 150 W DC/AC 12 V to 220 V boost converter found on ebay) and a MOSFET switched by an Arduino/optoisolator at 50 Hz. The ...
1
vote
2answers
193 views

PIC32 intermittent resets - revisited

This is a follow-up on a previous question that I have asked before, after making some changes as suggested through valuable inputs by other members, but with the problem persisting. In a nutshell, ...
3
votes
1answer
66 views

Relay coil suppression

I am following this application note for relay coil suppression. It suggests a diode and zener in series to be used for better contact life. I am using Panasonic ADW1212HLW relay. It's a 2 coil ...
1
vote
1answer
83 views

Choosing the right (flyback) diode to stop contacts (points) arcing (sparking) on solenoid (relay)

Clock with a simple electric remontoire, consisting of a solenoid, with an arm, that kicks back the main spring, rewinding it. Solenoid coil data: operating voltage: 12V-15V measured resistance: ...
0
votes
0answers
161 views

Buck-Boost Controller Arduino Nano vs STM32

I have 900W (150W*6Panels) solar panels and 12V inverter (1000VA) which have inbuilt PWM solar charge controller. The distance between pannels and inverter is around >10m and the wires are 6 sq mm ...
0
votes
0answers
34 views

SMPS topology for combination of current controlled rail and fixed voltage rail

I'm looking at designing a LED driving power supply that can interface with a universal AC main input (~90VAC-260VAC) and produce 2 rails at the output; one a current controlled rail, and the other a ...
0
votes
2answers
185 views

With Flyback Diode, still have spike.

I have the above circuit on a breadboard, where my PWM is coming form a microcontroller with its own current limited power supply. the motor is being powered from another output of my power supply. So ...
1
vote
0answers
93 views

Reducing AC/DC adapter (SMPS) output voltage

I have a AC/DC adapter P-1650-22 (used to power a notebook) laying around. I would like to use it for other purposes, i.e. as a constant voltage source for LEDs. The problem is, that the output ...
37
votes
4answers
94k views

How to choose a flyback diode for a relay?

A diode is put in parallel with a relay coil (with opposite polarity) to prevent damage to other components when the relay is turned off. Here's an example schematic I found online: I'm planning on ...
1
vote
2answers
60 views

Row Column Matrix Problem with Flyback Diodes

So I had a simple row column matrix which I am driving with mosfets to power solenoid locks like this: GC is ground via 1.5k resistor C is 24V via 1.5k resistor And these are the connectors: ...
1
vote
1answer
38 views

Coil causing spike and circuit reset?

I built a circuit that pulses a 50-ohm electromagnet when a 'trigger' magnet passes over a hall-effect sensor. This circuit swings a pendulum and simultaneously plays an audio clip as long as the 555 ...
1
vote
0answers
67 views

Hybrid Boost-Flyback Stability Issue

I tried to design a step up SMPS to create ~200-300v from a 24V input with an expected power of ~12W max. Since the project is for a hobby, I chose to attempt a hybrid boost-flyback converter to get ...
0
votes
1answer
357 views

How to determine correct replacement transformer for flyback converter in commercial product

I have an MPPT charge controller that has recently started behaving strangely and upon investigation I found a very hot mosfet and a transformer (below) that has clearly seen more heat than it should ...
3
votes
1answer
94 views

Flyback discontinuous mode, double voltage over the switch

Considering the following simplified flyback schematic. Which has the following voltage current graphs Why is there 2*Vin over the switch when the switch is turned off? And why is that change to Vin ...
5
votes
1answer
203 views

How to safely generate 200V from low voltage supply

Unfortunately, this post requires quite a bit of background if it's going to be useful to anybody (including me). I have been trying to build a relatively high voltage power converter for part of my ...
1
vote
4answers
134 views

Minimum specs before a flyback diode is needed for a relay?

Given a low power signal relay, 3V 140mW coil, controlled by a 2n3904 npn transistor, is a flyback diode required? At what point is a flyback diode needed for any given inductor? Is it total power, ...