Optocoupler, DC-DC converter, regulator

Thread Starter

Gpand

Joined Dec 11, 2023
82
I need an Optocoupler with DC-DC converter and regulator in a board or with chassis (with everything built in).

It has to pass 1mV from 0 to at least 20,000Hz (2 differential inputs and common/ground, 1 channel is ok) with no ripples or distortions or noise.

Usually what noises are present in optocouplers?

It needs DC-DC converter with output to the Optocoupler with less than 5mA and regulator to power the DC-DC converter.

Have you seen any finished product like this? If not, and need to build it. What components of best quality must one need?

I don't have much experience soldering so prefer a ready made product or you make me one (and I'll pay you for the service, thanks).
 

crutschow

Joined Mar 14, 2008
34,454
Optos don't have significant noise.
You description doesn't tell enough to allow us to give an informed answer.
Show us a schematic of the circuit so we know what you are referring to.
 

Thread Starter

Gpand

Joined Dec 11, 2023
82
optocoupler dc.jpg

The application is biopotential signal of 1mV to 10mV differential + and - with common (or ground), one channel only. The optocoupler will move the biosignal across the isolation barrier, and the DC-DC converter is needed to provide power for the isolated side while maintaining the isolation. The DC current of the input circuit of the optocoupler must be 5mA or human safe so in the event the optocoupler has fault and the isolation is broken, huge DC current from device (battery operated) wouldn't get into the skin (which is abraded so resistance is not very high).

The biosignal output must be similar to the input with no gain , no distortion and noises introduced. What optocoupler, DC-DC converter can be used for this purpose? Frequency range can be 2500Hz, doesn't have to be 20000Hz. What is the frequency response of a typical optocoupler?

Since the application can be used in any input in any generic device. Isn't there any finished product like it?
 
Last edited:

ericgibbs

Joined Jan 29, 2010
18,854
The biosignal output must be similar to the input with no gain , no distortion and noises introduced. What optocoupler, DC-DC converter can be used for this purpose? Frequency range can be 2500Hz, doesn't have to be 20000Hz. What is the frequency response of a typical optocoupler?

Hi Gp,
A typical opto coupler will not faithfully reproduce an analogue output signal, especially at those low bio voltage levels.

You need a preamplifier stage for the bio signal and an analogue opto coupler, similar to an HCNR200.

E
 

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