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Topic: SD card Module power input (Read 232 times) previous topic - next topic

1Blademaster

I bought an SD card module off Amazon (Link here) and it says that I can input either 5V or 3.3V, but whenever I try to input 3.3V with my Arduino Nano it doesn't work. However it does work with the 5V output pin on the nano, but i need to supply power using a digital pin so I can control when it's on or off.

I got suggested to use a 3V to 5V boost converter board (Link here) to increase the voltage from 3.3-5 volts, but this works at 500mA. Will that damage my module in any way? If it won't, would a 600mA board damage my module? If it would, how else would I be able to get 5V out of my Arduino Nano digital pin?

Thank you in advance  :D

pert

However it does work with the 5V output pin on the nano, but i need to supply power using a digital pin so I can control when it's on or off.

I got suggested to use a 3V to 5V boost converter board (Link here) to increase the voltage from 3.3-5 volts
This makes no sense. If your Nano is running at 5 V (which it must be if it has a 5V pin, then the digital pins are also at 5 V. So why do you think that that you would be powering the SD module at 3.3 V if it was powered from a digital pin?

I believe the SD modules will draw more current than the digital pin of the Nano can safely provide. You must be careful to never subject the Nano to its absolute maximum rating of 40 mA on the IO pins or you will damage or destroy it. 35 mA is the most I would ever consider drawing from the Nano's IO pin. So if you want to do this, you will need to control a transistor from the Nano's IO pin, and power the SD module through the transistor.

but this works at 500mA. Will that damage my module in any way?
The current rating of the boost converter only indicates the maximum current it can provide. You just need to make sure the number is sufficient for the current requirements of whatever you are powering from it.

1Blademaster

This makes no sense. If your Nano is running at 5 V (which it must be if it has a 5V pin, then the digital pins are also at 5 V. So why do you think that that you would be powering the SD module at 3.3 V if it was powered from a digital pin?

I believe the SD modules will draw more current than the digital pin of the Nano can safely provide. You must be careful to never subject the Nano to its absolute maximum rating of 40 mA on the IO pins or you will damage or destroy it. 35 mA is the most I would ever consider drawing from the Nano's IO pin. So if you want to do this, you will need to control a transistor from the Nano's IO pin, and power the SD module through the transistor.
The current rating of the boost converter only indicates the maximum current it can provide. You just need to make sure the number is sufficient for the current requirements of whatever you are powering from it.
It said online that it was a 3.3V board.. not sure if that's wrong or not but i've decided that i'll use a transistor instead of a boost board as this also saves space. Thank you :D

pert

OK, that would make sense if you have a 3.3 V Nano. I've never heard of such a thing, and there is no standard Arduino board definition for it (since it would need to use an 8 MHz crystal to run in spec), but it could easily be used with another board definition, or maybe even be overclocked to 16 MHz.

Regardless, the transistor is the way to go. The boost board would still result in too much of a current draw from the Nano's IO pin.

Lucario448

I bought an SD card module off Amazon (Link here) and it says that I can input either 5V or 3.3V, but whenever I try to input 3.3V with my Arduino Nano it doesn't work. However it does work with the 5V output pin on the nano
When the linear voltage regulator (the four-lead SMD IC) cannot be bypassed, I definitely doubt about the claim of working on 3.3 supply voltage.
Those kind of regulators drop voltage even when the input approaches the intended output, maybe so much that the card no longer works reliably.

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