[Hardware] Power Supply for CPAP/BiPAP electronics

Maciej Zarnowski
Site Admin
Posts: 29
Joined: Thu Mar 26, 2020 6:32 pm

[Hardware] Power Supply for CPAP/BiPAP electronics

Post by Maciej Zarnowski »

Hi!

We're almost ready with final design od our VentilAidor v3!
To complete the schematic part we need one thing: power supply circuit. Power system of respirator should be able to run from various power sources. We decided that it should accept 12-36V DC input. We need 50W max output power at 12V (average power consumption is about 20W).
We'd like to ask you, dear community, to help us with choosing the best dc/dc converter that'll do the job.
We're looking for cheapest yet reliable soluton.

Specs:
INPUT 12-36V DC
OUTPUT 4A@12V DC stabilized (propably it should be isolated as well, but let's see the pricing)

Could you please search for proper components (it should be available in large quantities or easily interchangeable with other parts).

We can use integrated converter or build our own using discrete components (we'll design PCB anyway).

If you do the schematic work, please consider using KiCAD for it. If you're familiar with other ECAD software, we'll convert it later (please attach PDF of schematics).

Daniel_ProtonDynamic
Posts: 2
Joined: Thu Apr 09, 2020 2:16 pm

Re: [Hardware] Power Supply for CPAP/BiPAP electronics

Post by Daniel_ProtonDynamic »

Hi!,

Why this kind of input voltage range?
Are you going to use battery supply for this device(LiPo, LiFePO4, PbSO4)?

What about efficiency and thermal behavior of converter?
Chip designs often have much lower real efficiency value than datasheet states. That implicates problems with their reliability.
Do you have enough space for radiator and fan cooling or device is going to be more compact?

And what about PCB layout and devices on board?
You need to consider big noise generated by chip and poorly designed buck converters. That ofcourse will affect functionality of microcontroller and sensor measurment circuits.

Maciej Zarnowski
Site Admin
Posts: 29
Joined: Thu Mar 26, 2020 6:32 pm

Re: [Hardware] Power Supply for CPAP/BiPAP electronics

Post by Maciej Zarnowski »

Device should be able to run from variuos power sources - 12V car battery, 24V truck battery, 19V laptop power supply, 24 or 36V industrial power supply etc.

Power module can be equipped with radiator and fan, but it can't be loud - we have to remember that it'll sit right next to patient.

The electrical noise etc. is why we're asking you to help. We're busy designing other parts of device, so we thought that community might help us with power supply module :)

Thanks for your input!

Daniel_ProtonDynamic
Posts: 2
Joined: Thu Apr 09, 2020 2:16 pm

Re: [Hardware] Power Supply for CPAP/BiPAP electronics

Post by Daniel_ProtonDynamic »

Hi,

Thank you for response.
The easiest and fastest solution in my opinion is to buy standalone converter with built-in EMI filters and basic safety mechanisms (overvoltage/overcurrent protection)

I've found this product in polish supplier TME:
https://www.tme.eu/pl/details/rsd-30g-1 ... mean-well/


However, we can also consider through hole components for PCB and build our own filter with protection/control circuits.

I don't know any electrical and idea schematics of device.
Is this power module should be standalone device or maybe you want to intergrate it with the rest of electronics(control, microcontroller etc.)?
If so, we could think about bigger PCB and more complex layout to design. I can help with it.

Post Reply