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Does anybody know the max current rating of the 3.3v and 5 v rail of the new raspberry pi 4? i could not seem to find anybody benchmark this, i have read from someone that the new RPI 4 has a new switching voltage regulator and was wondering is current rating.

If the power source matters i am interested in the normal USB-c port and the POE pins ( Direct to 5v rail)

Jack
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2 Answers2

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You will not find a specification, because there isn't one.

The Pi4 has the same power manager as the Pi3B+ and Pi3A+ so the current limitation would be the same (the PMIC is rated at 1.5A). The Pi3 regulator is rated at 1A and has been tested at 800mA (on 3.3V).

There is no polyfuse or limitation on 5V, so you could in principle draw up to the limit of the power supply, but this would be limited by the copper board traces.

See Raspberry Pi Power Limitations

Milliways
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    I was hopeful that there are some guys willing to break their PIs just to test this, But unfortunately there is non yet – Jack Oct 21 '19 at 21:28
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30mA for 3.3V (GPIO pins) For 5V there is no actual limit because that is directly attached with the power chip. Using 5 V rail is dangerous than using a USB type-C.

Sohan Arafat
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    The regulator's 3V3 rail can support 1.5 A so even accounting for the Pi's own consumption and the regulators total load the claim of 30 mA seems a little unfounded. – Ghanima Oct 21 '19 at 18:52
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    i agree im pretty sure i have device that have drawn atleast more than 100mA from the 3.3 rail, maybe you mean GPIO ? – Jack Oct 21 '19 at 19:15
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    @Ghanima do you want to post that as an answer ? or perhaps you lack information on the 5v rail? – Jack Oct 21 '19 at 19:18
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    Actually I am talking about gpio. yes you are right jack – Sohan Arafat Oct 21 '19 at 19:41
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    @jack sorry, but since my comment is just a fragment I cannot turn it into a well-researched answer. – Ghanima Oct 21 '19 at 20:03
  • I think this answer confuses the GPIO pins with the 3.3V bus pin ON the GPIO rail. The question asks about how much power can be drawn from the converter and power buses -- I think. Mentioning the actual processor-controlled I/O pins will just cause confusion. –  Oct 22 '19 at 20:43