Electronics > Projects, Designs, and Technical Stuff
Analog optocoupler
Doctorandus_P:
Does the frequency response have to go down to DC?
Can you use a simple transformer?
And why would you want an analog signal on the secondary side?
It's much more common to have some signal conditioning and feed an analog signal to an ADC and then push a digital data through an isolation barrier, and never convert it to analog anymore.
T3sl4co1l:
What is the common mode voltage, DC and AC?
If it's nearly zero (common ground, just noisy), use chokes (CMCs) and diff amps!
Tim
ricko_uk:
Yes. Thank you Tim! :)
fcb:
HP/Broadcom/whoever still make an optocoupler used for video isolation - it’s pretty linear and there are some nice app notes. HPCN4582 or some such.
There used to be a nice optocoupler with two photodiodes in it (2nd was used to linearise the LED) - it was designed for DC accurate circuits.
Zero999:
I tried Googling for HPC4582 but couldn't find anything.
How about using a digital isolator and PWM? Here's an application note from Silicon Labs.
https://www.silabs.com/documents/public/application-notes/AN614.pdf
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