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.

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Secondary voltage spike in flyback transformer

simulate this circuit – Schematic created using CircuitLab I am using a TNY264 IC to make a custom flyback transformer. (U1 is the TNY264.) The primary to secondary turns ratio is 10 with the ...
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2answers
2k 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 ...
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239 views

Methods for increasing output power and efficiency of a ZVS flyback driver

I have built the following ZVS driver: I am using this circuit at a resonance frequency of 150kHz. My hope is to be able to modify this circuit for wireless power transmission. With that being said, ...
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1answer
225 views

Flyback converter can't power load

I'm working on a Nixie tube clock and I'm having issues with the power supply. It's a flyback converter based on the LT3757 and the Coilcraft DA2032-AL flyback transformer. I designed to work with an ...
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1answer
139 views

FAN6754 flyback converter-overcurrent problem

I have a design 193V output voltage and 700mA current, but when the current drawn from output, the auxilary winding voltage fall down, and IC shut down PWM gate signal as you can see in the attachment ...
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590 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 ...
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144 views

55-650V to 5V DC/DC convertor design

For an application I am building I need a custom DC/DC convertor that can convert a voltage ranging from 60V-600V to a contant voltage of around 5V. Using the TI Webench with the paramaters Vin_min = ...
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1answer
2k views

High voltage (2-6 kV), high frequency (20-50 kHz) power supply how to achive

I need to make a high voltage (2-6 kV), high frequency (20-50 kHz) power supply in order to generate cold plasma (in Ar gas). I use a fly back circuit (found in web) could allow me to to that. The ...
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69 views

Flyback diodes instead of a resistor in series with a capacitor in parallel with the inductor

Why do people use flyback diodes instead of a resistor in series with a capacitor in parallel with the inductor? Wouldn't it be just as good? It would also have the benefit of working with motors that ...
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2answers
63 views

BJT Collector-Emitter Breakdown Voltage

I'm developing a flyback converter with the FT838NB1 IC, and I got some doubts about the Collector-Emitter breakdown voltage of the integrated NPN switching transistor. IC datasheet link: https://...
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1answer
61 views

Safely probing low voltage isolated DC/DC converter rails with an Oscilloscope

Lets say you have a flyback with a 20V dc input and 2 secondary side outputs, 5V and 12V. The 20V power in is provided by a benchtop power supply. What is the safe way to measure the input and output ...
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1answer
49 views

Determining error in output voltages of a flyback converter

I'm currently designing a flyback converter and I just want to know how the error tolerances are calculated for a multi output flyback converter. I calculated the required primary number of turns: ...
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27 views

Flyback converter Transformer calculation verification

Kindly verify the transformer design for this wide input power supply using LM5022 i am designing the power supply for my solar inverter in which output of solar panel (750Vdc to 800Vdc) directly fed ...
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61 views

How to Determine Input Capacitor Value for Peak Power Requirement

For flyback SMPS, how do we know that our input capacitor value is sufficient for some peak power requirement? I understand that bigger input capacitor will have more advantage on this peak power. ...
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1answer
267 views

Reduce Flyback Reflected Voltage Ringing?

I have a step-up flyback design with the following parameters: \$V_{in}=24V\$ \$V_{o}=150-350V\$ \$P=15W\$ \$N_{ps-ratio}=1:7\$ The transformer is not ideal with 1:7 and the inductance is a bit off, ...
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121 views

Actual Saturation Current Limit & Air Gap Based on Core Datasheet

I'm estimating actual peak current limit & air gap height based on the actual transformer core parameter in the datasheet. This flyback transformer is designed based on 24V output with 50W rated ...
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1answer
789 views

Measure leakage inductance of flyback transformer with multiple secondary windings

I have a transformer consisting of one primary winding and 3 secondary windings. Now I want to measure the leakage inductance at the primary side, so I need to short the secondary windings. Most of ...
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34 views

Simple Synchronous Rectification of Unidirectional Motor?

I'm trying to drive a high current, low voltage motor (24V 100A cont.). It previously used a very large and overpowered H-Bridge (16 FETs). The system only can rotate 1 direction, and is required to ...
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121 views

Using schottky diode near reverse breakdown region

I am currently using a 1N7070 schottky diode as the output rectifier for a flyback converter. The designed reverse blocking voltage is 70V. However, due to leakage elements I am seeing a transient ...
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1answer
69 views

What is the effect of doubling the airgap in a flyback converter?

If I understand correctly it would flatten the hysteresis curve. So it would allow to store more energy and it would also decrease the permeability of the core. Would it have another effect or will ...
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150 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 ...
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2answers
723 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 ...
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150 views

Flyback Converter with multiple DC outputs

I am trying to understand how (step up) Flyback Converters work, since I need to design one myself. I am not at all new to electronics and I understand the fundamentals behind them, but I am totally ...
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203 views

Possibility of hybrid forward-flyback topology

Within the context of isolated converters, the flyback topology is nice in its simplicity as can be the forward topology, in spite of needing a second primary reset winding. However, both make poor ...
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1answer
281 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 ...
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236 views

UCC28C44 flyback start-up problem

I have a problem with a design of a flyback converter for a power supply. I am using UCC28C44 PWM IC. Converter should star up with at least 200V and VDD should be charged to 14V when 15V should ...
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721 views

Flyback Converter Design Help

I am unsure whether I should edit on my previous question or create a new one. Please give me your feedback on the proper way of doing it here.Back to the question, I have struggled for the past few ...
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194 views

Flyback diodes for motors wired in parallel

When driving two DC motors wired in parallel, do they each require their own flyback diode or can they share a single diode?
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465 views

Flyback transformer for offline switcher ac-dc PSU

I am designing a 5V 3A SMPS circuit using Viper22a (60 kHz switching frequency) and transformer design is turning out to be the most difficult part of it. Actual load will draw less than 10 watts but ...
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363 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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746 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 ...
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194 views

How can I add redundancy to the flyback diode protection across an inductive load?

Dear StackExchange users, I want to add redundancy to a flyback diode system that is protecting an N channel MOSFET from flyback of an inductive load but I don't know how to accomplish this! I am ...
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21 views

LT Spice simulation error: 'Time step too small'

Could someone get this up and running? Tried all the possibilities but it does not seem to work still. Here I am just trying to simulate the linked circuit here .. PMP7763 design reference
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17 views

high voltage isolated dc/dc converter watt selection problem

I am a beginner circuit developer. I used a TI WEBENCH POWER DESIGNER, to make all-in-one battery management system power design. POWER DESIGNER made a recommendation like the picture. Specifically, ...
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75 views

how this equation is obtained for calculating input capacitor of a fly back presented in UC3842 datasheet?

i know that it refers to stored energy formula for a capacitor according to voltage variations. but i dont have any idea about the specified part. where did this part come from? https://www.ti.com/lit/...
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45 views

Flyback power supply - 132 kHz radiated magnetic field issue

I request your expertise on a radiated magnetic field around 132 kHz (low frequency) on a Flyback power supply. I'm using the LNK3694 driver with a switching frequency around 66 kHz. Using a circular ...
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55 views

Self-Oscillating Flyback Converter

I am trying to design a self-oscillating flyback converter using the circuit below as a reference. I understand the ton time depends upon the values of Rst, Cf, and Rf and the switching mosfet, M1 ...
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39 views

What is the stuff hardened on an old flyback transformer?

I am restoring some vintage old Mac computers with the integrated CRT display. These have a flyback transformer on their analog board. Part of this device is some hardened brown/orange material at the ...
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1answer
31 views

Deviation in the switch current in a flyback converter

This is the current waveform of the switch and the Vds of the MOSFET. Ideally, the current should fall off in a normal fashion with the switch turns off. Here, the current fall stops and becomes flat ...
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63 views

Transient Spice Simulation of Flyback Converter

I have created a simple model of a flyback converter using the PWM switch model by Vatche Vorperian. The simulation should be transient showing the switch events. In the picture below you see the ...
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47 views

DCM flyback converter

Recently,my research will focus on DCM flybck but I don't have any theory on DCM. I don't know how to start I want to model the small signal model. Do you guys can suggest me some paper or book let me ...
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2answers
49 views

how to choose diode for PWM of high amperage solenoid?

I'm making a pulseable solenoid circuit via PWM at around 20 hz. THe solenoid is a heavy industrial type that pulls a whopping 18 amps. My snubber circuit gets hot and burns up as the current is too ...
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62 views

Trying to damp transformer output ringing of Flyback Converter when primary FET turns on

I have a flyback regulator with some output ringing spike problems. It is a 70-130V input with 6V regulated output and 75V unregulated output based on the LM5021 flyback IC. When going from no load to ...
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55 views

Spark Gap Circuit Creating Unpredictable Current Spikes, What is Causing This?

I have recently been messing around with bug zapper / spark ignitor circuits as a way to learn more about high voltage electronics (This is my first foray into high voltage territory other than a few ...
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64 views

Secondary snubber in flyback converter

I am designing a flyback converter. Input = 180-240 Vac Output = 15 V, 0.4 A The secondary output seems to be oscillating when the diode is turns on. Oscillating frequency is around 27 MHz. I am using ...
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71 views

SMPS Transformer Primary Winding Ringing

We are working on a 24V 4A flyback SMPS design. But when we analyze the primary winding of SMPS transformer, we are determining very high voltage oscillations(ringing) up to 350V. But our DC bus is ...
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67 views

Below given circuit, when given 24V DC supply for 30 seconds, the IN5408 diode shorts out at a rate of 1 in 5 cases

With circuit given below, when given 24V DC supply for 30 seconds, the IN5408 diode shorts out at a rate of 1 in 5 cases. This is an EMR circuit. What could be the possible cause for this issue?
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63 views

SMPS transformer secondary voltage drift

Please see the simple SMPS buck circuit below (24V to 12V) Notice the load on the 'first' secondary coil is about 100mA (marked 'fb' This coil is used as the feedback to the MC43063 to regulate the ...
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36 views

Does a spinning plasma vortex work with ac?

I am making some plasma arcs with this flyback transformer and I power it by passing the exposed wires of my charger to a halogen ballast. I've seen people online make spinning plasma vortexes I was ...
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43 views

Reduce capacitor charging time

i am using flyback converter to charge a capatior 250uF 300V how can I reduce the charging time to 1 second OR how to increase current. 28V DC input voltage transformer output Voltage is 300V PWM ...