Power Sustainable

Hi, everyone.

I'm currently on a new project, a prototype of a machine using Arduino Mega 2560 as my microcontroller. However the problem is that, I'm curious on how this microcontroller power distribution works. Is it can sustain or not. Here is my circuit for my project.

As you can see, I'm using 10 voltage regulator, each with 5k resistance as analog input A0 until A9. Next, I'm using 10 pullup resistor as digital input each with 10k resistance from pin 22 until 31. Afterwards, there's 10 digital signal output to relay module output (normally low) from pin 32 to 41. Lastly 10 pwm signal from pin 2 to 11. In conclusion, here's the power distribution for the project:
5V from the arduino to the:
-10 x 5k Voltage Regulator
-10 x Arduino input pin parallel to 10k resistor
-10 x Relay output (normally low)

  • Power supply to Relay module(Vcc different power supply with JD-VCC)
    -10 x PWM signal
    -Relay Module power supply

For the power supply of the Mega, I'm using adjustable 5A DC-DC Power Module with 9V to Vin pin. Voltage regulator and pullup resistor is powered by 5V pin from the Arduino Mega 2560. Can it sustain the power distribution? Or should I use seperate power supply for the analog and digital input? Is it permissable to do that at the first place? How?


That should be less than 100ma total which should be okay but is about the practical limit. 9 volts in at 100 ma load is about 400mw dissipated by the 5 volt regulator (9-5)*iLoad.

But - If you’re suppling power externally, it is always best to use a 5 volt supply and avoid the barrel jack input.

PS: you can test your board by applying the 9 volt supply and load the 5V pin with a 50 ohm resistor. Let it run for 10 minutes and check the temperature of the 5V regulator. If you cannot leave your finger on it, it’s too hot and the load is too high. Check it after 30 minutes and if okay to touch, it’s okay to use.

Alrighty, thanks for the reply. So should I lower my power supply?

That may help but it depends upon the regulator ic used and it’s voltage dropout specification. The official Mega uses the MC33269 which has a dropout of 1.0 volt which means it maintains its regulated output of 5 volts with 6 volts input. That would lower the temperature rise but if you’re going with a lower voltage - don’t bother.

Use a 5 volt 1 amp supply and you’re done with supply concerns and power budgets.

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