Multiple Voltage Regulators

Hello everyone,

I am fairly new to the arduino MCU world and I have some questions.
I have a project which I wanna power with Li-ion Batteries.
In my project I will use the Arduino Nano 33 BLE(needs 4,5V-5,5V), a low-power ECG module (that works on 1.1V), a Biometric Sensor hub( that needs 1,8V to work, and 3.5V to 5V for led).
These are 3 different voltages. Can I power them through 3 different voltage regulators each starting from the power line? Is there any standard problems I will have to face when 3 different voltage regulators start from the same power line?

Thanks in advance for your time!
Orestis V.

From what you wrote 3 regulators and level shifters should work well. Proper regulator filtering would be a good idea.

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Yes.

Since the OP didn’t mention level shifters I am compelled to reiterate:

Your real problem will be ensuring that the logic levels of the various things you are hooking up are compatible OR properly routed through level shifters.

Level shifters can take many forms, google is your friend here.

a7

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Just choose small (compatibly with the current you need) DC-DC converters, and then filter very well their outputs, don’t use linear ones cause they waste a lot of power in heat, especially if the output voltage is much small than the input voltage …

Hi,
Welcome to the forum.

Please read the post at the start of any forum , entitled “How to use this Forum”.
OR

Can you post a basic diagram of how you envision connecting your components, even a hand drawn block diag to show power supply wiring.

Thanks… Tom… :grinning: :+1: :coffee: :australia:

Hello everyone,

I am sorry for responding late but I was working on my project.
In my project I will use Arduino NANO 33 BLE, MAX86146(for PPG and HR),KX122 (needed for MAX86146), MAX30003( for ECG) and MAX30208(for temperature). I would post their datasheets but from the guide you posted I understand that is not the right way.
For my power, I have decided to use 2 MCP1700 and 1 MIC2877 voltage regulators.


I have some questions.
1)On the MIC2877 regulator what I am supposed to do with the EN pin and the PG pin?
2)There are some triangles(ground signals) in my schematic, am I supposed to ground them or power them?
3)On MAX30003 it is stated in the datasheet that I.C. pins should be connected to the AGND. I did not understand if this internally on the board or I should ground them all together.
4)MAX86146 needs an Accelerometer in order to make correct measurements. I know that Arduino Nano 33 BLE have an integrated IMU, which I understood that I can access through the I2C, but MAX86146 is designed to take the Accelerometer measurements through SPI, that is why I added the KX122 Accelerometer, is there any way to take this measurements from the IMU of Arduino board?
5) This device will be placed on the wrist(Device 1). There will be another device placed on the leg(Device 2), which will have a GPS and another MAX30208 for temperature measurements.
Can Device 2 send data through BLE to Device 1, and Device 1 send data through BLE to an android phone at the same time? To rephrase that, can one device receive and send data through BLE simultaneously?
6) I power my Arduino NANO 33 BLE board with 5V through the VIN pin, is this correct? I understand that there is a integrated regulator on the board that takes 4,5V to 21V and brings it down to 3,3V. Have I misunderstood that?
7) The MAX30003 has an external oscillator which needs to be connected to the MCU. I know that Arduino NANO 33 BLE has an internal oscillator, can I access that oscillator through Digital Pins?(that is the dotted line)
In this research I did not check the power consumption at all. If the power consumption is too high, I will probably try to work with the MAX20360 for power management.
Feel free to add any comments or suggestions or point out any mistakes!
Thanks everyone in Advance.
P.S.
The png might be a little too small, but if you download it and zoom everything seems pretty clear!

Hi,

This might help.

But as it has a DC-DC converter I think your connection should be okay.

Tom… :grinning: :+1: :coffee: :australia:

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Hi,

Connect it to Vin via a 10K resistor.
Tom… :grinning: :+1: :coffee: :australia:

HI,[quote=“orvasson, post:8, topic:850713”]
2)There are some triangles(ground signals) in my schematic, am I supposed to ground them or power them?
[/quote]
They are all connected together and to the Lipo gnd/neg lead.

Tom… :grinning: :+1: :coffee: :australia:

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Hi Tom,

Am I supposed to do that for the PG pin also?

Thanks for your time and responses!

Hi,

That is an output pin and if you like connect it to a 10K pullup to the 2877’s output pin.
It is used to signal that the 2877 is functioning and outputting current, you don’t have to use it.

Thanks for setting your questions out in point form, makes them easier to read and respond.

Tom… :grinning: :+1: :coffee: :australia:

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Hi,

I am not very familiar with the 33 BLE so you may need to wait for someone more informed to advise you.

Tom… :grinning: :+1: :coffee: :australia:
PS. There is a 33 BLE section in the forum, you may have to ask there.

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