The number of PVC flying caps

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morris_test
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The number of PVC flying caps

Hi Dialog support,

I would like to minimize the total area of DA9313 design and optimize the cost of external components as well, so I plan to reduce the PVC flying caps from 4 x 47uF to 2 x 47uF.
Could you please let me know what the impact would be ? Do you recommend using that ?

Cheers,
Gordon

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ED_Dialog
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Joined: 2017-09-18 11:54
Hello Gordon

Hello Gordon

It depends. Reducing the flying capacitor value will impact efficiency. Reducing the quantity of capacitor may impact reliability. The flying capacitor must have the appropriate ripple current rating to meet the maximum 20ºC temperature rise requirement.

CFLY per phase must be rated to ≥ 18 μF @ 5 V, IRMS = 8 A. Note that there are two CFLY in parallel per phase, therefore each capacitor must be rated to ≥ 9 μF @ 5 V, IRMS = 4 A.

 

Kind regards,

Elliott Dexter 

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