Require High speed, High voltage at detecter optoisolator

[Murugesh_89]

Hi,
I am using 3.3V operating microcontroller. I want to run the servo motor. The open collector input of servo drive requires the 24V pulses.

Also i want to optically isolates the microcontroller part from the servo drive section.

Can anyone pls give me any Optical isolator( High speed, Vcc max rating: 30V at the output/detecter side) part number for this?

Thanks..

 

[FvM]

Not clear what you mean with "open collector input"? If you are talking about an active low input with 24V pull-up (next best fit) to be driven by a NPN o.c. output or switch to ground, what's the input current?

24V inputs are rarely high speed, standard opto couplers are able to switch at least with several kHz, isn't that sufficient?

 

[Murugesh_89]

Hi,
Given here the "open collector input" image..



The datasheet of servo drive specifies that "max. input pulse frequency of Open-collector input is 200kpps." Will the standard opto couplers suits this?

 

[betwixt]

200K pulses per second is fairlty slow in electrical terms, most opto-couplers will work at that frequency.

It isn't a ll clear what you are asking about though. There is no such thing as an 'open collector input' so giving it a voltage rating is meaningless. From what I can tell from the diagram, it is trying to tell you the module has 24V present at the input pin and you can pull it to ground with an external open collector output.

So why are you asking if a standard optocoupler is suitable? There is already one in the module. If you need absolute voltaic isolation you can use the transistor side of a standard optocoupler in place of the transistor in the diagram. Any type that has VCEo > 24V should work.

Brian.

 

[Murugesh_89]

If you need absolute voltaic isolation you can use the transistor side of a standard optocoupler in place of the transistor in the diagram. Any type that has VCEo > 24V should work.

Brian.

Well exactly. I wanted to have a optocoupler( output transistor side ) in the place of transistor in the diagram.

Thanks for your detailed answer

 

[betwixt]

You don't need one in that case, you already have access to an isolated input across pins 36 and 37.

If you leave out the link between pins 35 and 16, you can drive the internal optocoupler LED from an isolated source and it doesn't have to be 24V, you can use anything from about 2V upwards.

Brian.