Design a flyback transformer for charging defibrillator

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Discussion Overview

The discussion revolves around the design of a flyback transformer intended for the controlled charging of a defibrillator capacitor, which operates at high voltage. The charging process is managed using PWM to control the transformer switching via a MOSFET. Participants explore various aspects of the design and safety considerations associated with high-voltage applications.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • Some participants inquire about the design specifics of a flyback transformer for charging a defibrillator capacitor, emphasizing the need for controlled charging.
  • One participant references a paper that may provide useful insights but questions whether the original poster has fully understood it or if they are working on a school project.
  • Concerns are raised regarding the safety of working with defibrillator capacitors, which can store lethal amounts of energy, suggesting that proper guidance is necessary.
  • Another participant notes that the referenced paper does not cover the actual transformer design, highlighting the importance of selecting an appropriate core and determining the winding specifications.
  • Participants provide links to various resources and design guides from manufacturers to assist in the transformer design process.
  • There is a mention of the potential dangers associated with high-voltage applications, with a suggestion that the forum may need to limit discussions on such topics for safety reasons.

Areas of Agreement / Disagreement

Participants express concerns about safety and the need for proper oversight when dealing with high voltages. However, there is no consensus on the specifics of the transformer design, as multiple viewpoints and resources are presented without a clear resolution.

Contextual Notes

Participants note that the design of the flyback transformer involves detailed considerations such as core selection and winding calculations, which may not be straightforward for beginners. There are also implications regarding the risks associated with high-voltage components that remain unresolved.

Who May Find This Useful

This discussion may be of interest to individuals involved in electrical engineering, particularly those focusing on transformer design, high-voltage applications, and safety protocols in experimental setups.

swathy
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how can i design a flyback transformer for the controlled charging of defibrillator capacitor(high voltage). The charging is controlled using PWM which controls the transformer switching using a MOSFET.
 

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swathy said:
how can i design a flyback transformer for the controlled charging of defibrillator capacitor(high voltage). The charging is controlled using PWM which controls the transformer switching using a MOSFET.
Welcome to the PF.

It looks like the paper you attached has a pretty good explanation for your question. Have you read it? Is there some part that you do not understand? Is this for schoolwork?
 
Sorry to be a pain here but is this project aimed ant actually building something? If it is, then you need to be under the direction of someone who is competent to handle very high voltages. By their very nature, Defib Capacitors store enough energy to kill you. I'm not sure what the Mods would think about this? eh, berkeman?
 
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sophiecentaur said:
eh, berkeman?
:smile:
 
sophiecentaur said:
By their very nature, Defib Capacitors store enough energy to kill you.
Yep. And it's mentioned on page 4.
CAUTION: The charged capacitor used in the example can
provide a LETHAL shock.
 
swathy said:
how can i design a flyback transformer ...

That paper stops short of designing the actual transformer.

The Devil is always in the Details. You've got to pick a core and figure out how much wire to wind onto it.

TI has a guide here
https://www.ti.com/lit/ml/slup127/slup127.pdf

core manufacturers have design guides but they tend to be cryptic because the folks who write them are so experienced they have difficulty making their shorthand easy for beginners to grasp.
Magnetics Inc is an old line supplier with an extensive library.
take a look here
https://www.mag-inc.com/Design/Selection-Guide
https://www.mag-inc.com/Design/Design-Guides/Transformer-Design-with-Magnetics-Ferrite-Cores
https://www.mag-inc.com/getattachme...oductDistributionChartWaAc2012.pdf?lang=en-US

hope that gets you started.

Coilcraft has design tools that help you pick one of their standard transformers.
http://www.coilcraft.com/transformsel.cfm
http://www.coilcraft.com/prod_cap_charger.cfm

old jim
 
Last edited:
dlgoff said:
Yep. And it's mentioned on page 4.
Safety / danger would probably also be mentioned in paper on using TNT but PF would still urge caution and probably distance itself from too much discussion. I think it's in the rules.
 
The OP has not been back in almost a week, so I'll go ahead and close the thread for now. @swathy -- send me a Private Message if you would like this thread re-opened for discussion.
 
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