I am using heater circuit for bio-medical application ( to achieve 37 degree Celsius for blood samples ). I am using opto-isolator P781F to isolate control circuit ( Micro-controller I/O pins - H1G shown in schematic) and heater.
Link for opto datasheet: http://www.farnell.com/datasheets/90914.pdf
My schematic is as shown below:
H1G= I/O pin from LPC2138 controller
Heater = 12V,23 Ohms Silicon Heater
But, I am little worried as I have connected controller I/O pin directly to cathode of LED of opto. So, is there any loading issue I can face, what parameter will come in picture to check I/O pin source/sink capacity with OPTO pin.
Will this cause any loading or impedance problem? Do I need any buffer circuitry from controller I/O to opto circuit.
Thank you in advance.