Stepper driver signals across a 3.5KV isolation barrier

[eem2am]

Hello

I need to drive a stepper motor from a microcontroller across a 3500V isolation barrier.

-Using a NJM2673 chopper stepper driver

(i.e. the micro is isolated from the rest of the circuitry, its on the secondary of the offline SMPS)

Do you know the cheapest way?

Is it opto’s or coupled coils?

 

[FvM]

First you should specify the control signal frequency range (Waveform, pulse frequency). Obviously, "coupled coils" can't transmit digital logic levels without a DC restore circuit.

 

[eem2am]

-microcontroller output is square wave, and it is at 10KHz

 

[Mr.Cool]

analog devices makes "coupled coils" for exactly this purpose. it has integrated technology to handle even DC signals, so you can hold an ON signal indefinitely for example. the working voltage is 500V and the isolation i forget, but it was high.. maybe high enough for you. they are smaller than opto couple chips too which is a bonus. don't know about the price.

 

[Siniša]

This dual opto is about $1CDN in single quantity at Digikey, but there are virtually tons of optos with specs that satisfy your requirements. 5kV rating is not rare at all. Milling PCB bellow opto to extend isolation distance is good idea for HV.