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Adding a capacitor to protect FAPs when using cheap buck power supplies

Fauxtawn

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Jan 25, 2022
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I plan on building a portable FAP laser. The idea is to use some cheap power supplies in parallel to power it.

Hf5d97e0427a44a4d816a96fc5839dd55K.jpg


However the problems as I understand it are:

1) These power supplies don't like being wired in parallel because one might backdrive the other. - I plan to use Shottky diodes to prevent this.
2) Some say these power supplies might introduce a voltage spike when turned on.

I'm thinking I can use a capacitor to flatten the voltage spike. If this is a good idea, any recommendations on what kind/size capacitor I should use? Thanks!
 



Giannis_TDM

Well-known member
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Apr 27, 2019
Messages
738
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I plan on building a portable FAP laser. The idea is to use some cheap power supplies in parallel to power it.

Hf5d97e0427a44a4d816a96fc5839dd55K.jpg


However the problems as I understand it are:

1) These power supplies don't like being wired in parallel because one might backdrive the other. - I plan to use Shottky diodes to prevent this.
2) Some say these power supplies might introduce a voltage spike when turned on.

I'm thinking I can use a capacitor to flatten the voltage spike. If this is a good idea, any recommendations on what kind/size capacitor I should use? Thanks!
Due to the way that their feedback is done, I suggest that you do nothing of the short, instead, get a low voltage high current constant voltage CPU PSU to add a shunt and a dual opamp and tap into its feedback to turn it into CC.

Look into Marco rep's laser driver for this exact application (or if you can find the dc-dc module, just build his, developed to do this exact thing.)
 




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