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We need to design a power supply for a 3.3 V WiFi-device. But there are quite some current spikes during WiFi startup. Using the design below there is a risk the 5 V (250 mA max) supply (not mine) will "fold back".

I thought of adding a large capacitor but am not sure how to do this. I found the Richtek RT8032 which seems to do what I need but it is eol. TI and Analog seem to have a lot but nothing exactly what I need.

enter image description here

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  • \$\begingroup\$ Ask a question and it likely gets answered. Right now it is difficult to understand what is the question. \$\endgroup\$
    – Justme
    Commented Jan 22 at 11:41
  • \$\begingroup\$ Capacitors work only for a short time. It looks as if you need to find out what the actual current requirements are, and to design a supply that is able to handle that. \$\endgroup\$
    – CL.
    Commented Jan 22 at 12:03
  • \$\begingroup\$ Energy out < energy in. If you can't supply enough of it from your 5 V supply, you need to take it from somewhere else. Please measure current consumption over time and calculate how much energy you need to store in your capacitor. If more than ms of time, you may be better off with a battery. \$\endgroup\$
    – winny
    Commented Jan 22 at 12:51
  • \$\begingroup\$ Calculate the duration of the current spikes and then calculate a capacitance. As they get longer you'll end up with even higher capacitance. Higher capacitance is not always good i.e. it may lead to instability of the supply that you put the high capacitance across. \$\endgroup\$
    – Rohat Kılıç
    Commented Jan 22 at 12:55
  • \$\begingroup\$ the question was for help with this design but that got deleted \$\endgroup\$
    – boddeke
    Commented Jan 22 at 13:15

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