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Isolating a board from actuator and position sensors

Question asked by rdowning on Mar 16, 2011

Brian, I had a customer ask this recently.  How can we help?


I have a processor board that needs to be isolated from an actuator and position sensor.  From the processor board I need to provide 5V of isolated power at about 1W to the actuator. The switching regulator that I built with an optocoupler feedback seems to be fine for static loads but when the motor runs the output voltage does not stay stable and bounces around by several volts.  The problem is that the load current on the isolated 5V changes from 50mW to 1W when the actuator runs at a rate of 10ms/cycle.  Using a simple open loop switcher and linear regulator is not an option because the efficiency loss.  I am looking for a simple isolated 5V to 5V regulated DC supply that is less expensive than a module. Also, the  FPGA on the processor board has a standard SPI port to communicate with the actuator and position sensor that also needs to be isolated.  I don’t have a lot of space on in my PCB.


Message was edited by: rdowning