I am working on a circuit design where a heater (10 Watts) load is switched ON and OFF using a relay. The relay is in turn switched ON and OFF from N-MOSFET. MOSFET is switched ON and OFF using a Micro-controller and an Opto-Isolator. Our concern is that in case of MOSFET failing short/closed the relay will always be ON and the heater will stay ON. Is there any way in the switching circuit design to cut off the power in case of MOSFET failing short? Or is there a way that MOSFET always fails OPEN?
Thanks in advance for your time and help.