Using pic chips in a noisy electrical environments

[senojlr]

Thanks Mat and Sougata. I understand now. I am just an amateur and I really appreciate you guys taking time to help me. I am going to try this on a prototype board that I am working on. Thanks again for the help.

[Charles Linquis]

I recently had an application where the power was very noisy. The PIC had its own power and ground planes, and hundreds of microfarads of capacitance. Nothing worked until I decided to feed the PIC power plane from the main power through a Schottky diode (very low Vf type). I have 100uF and lots of .1uF caps on the PIC side of the diode.

Now, when the power on the "Main" side drops to a low voltage for a few nanoseconds, the PIC runs on the capacitor "battery". The circuit is now perfectly stable, and even though the PIC now only has 4.53V for VCC, it is still above the minimum of 4.2V.

Charles Linquist

[Acetronics2]

Hi, Charles

I also use that solution for a car electronic ignition PIC supply ... and the power Transistor or IGBT is driven through an opto-coupler !!!

No problem ...

Alain