Galvanic isoltion

if you are working with either a control voltage or serial data, a fiber optic transmitter/receiver combination would provide the most isolation.

In the past, I have used this combination to remotely trigger a high-voltage power supply with good results and no fried circuitry at the trigger source.

Sometimes coupling the two 0V rails across an isolation barrier with a very high voltage capacitor can achieve the desired result. What are you trying to do?

What I have to do is to put galvanic isolation in a circuit where the voltage is chopped. I need this isolation to avoid the common mode noise. Now, I'm looking for different alternatives such as optoacoplers, isolation amplifiers... etc.

Can someone give me something like a list of the components or different ways that give galvanic isolation?

1.) Transformer.

2.) Optocoupler (with or without length of fiber). Difficult to achieve accuracy unless converting to a digital steam.

3.) Capacitor (won't get rid of common mode noise).

4.) Mechanical linkage (just joking).

5.) Radio (just joking).

Why don't you want to use a transformer?

Because I've to work with high frecuencies (f> 100kHz). Although I just find some that can work with much more.

But I prefer something smaller and less heavy, thanks.

http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&keywords=pulse+transformers+isolation+and+data+interface&x=20&y=14

Hi FrederikoII,

sorry, but your questions should have a bit more substance to give you the right answers.

1. What kind of a signal do you want to want to transmit, analog chopped (= different magnitudes) or digital (only one level, and if yes, which one, because digital is no longer 5V but nearly anything between 1 and 18V DC) ?

2. Whats the maximum frequency you need to transmit ?

3. Whats the distance (only inside a chip or more) ?

4. Whats the isolation voltage you need (not only the test voltage for xxx seconds but permanently allowed at which pulse shape) ?

5. Which I/O-capacitance will be allowed ?

6. If analog, which accuracy ?

7. Environmental conditions (e.g. optical RX/TX may be temperature depending which influences (5) ?

Regards Uwe

Regards.

Then "Opto-Isolator" is the option.

In open-loop control only single unit will work.

In Close-Loop control two are required.

Have a fine day !