Schematic Review

General Discussion
#1

I’m a bit new to this site, as well as to building schematics in general and I wanted to see if someone could have a look at my schematic.

The project is to build a MOSFET relay shied for the Particle Photon. The plan is to have one power supply that will both power the photon and one motor/pump at a time on each channel. I’ve included a DC/DC buck converter in this as well.

Here is a link to the schematic, please go easy on me :grin:

https://upverter.com/djbetterly/5813d68bcf99e645/MOS/

Thank you,
Dustin

#2

Hi Dustin,

I took a look at your schematic, to me it seems that the outputs on the connectors
J25, J26, J27, J37, J42 and J47 are always connected to 12V and GND. If what you are
trying to do is drive an inductive load by using MOSFETS in a commom drain configuration you need to make a few changes to your circuit.

Remove the GND connections from the connectors and place it instead at the source of each transistor. If you want the leds to flash everytime the transistors are ON you should place them and resistors between the D0, D1, D2, D3, D4, D5 signals and GND. But first make sure the PHOTON digital outputs can handle the current demanded by the leds, if not you should use a buffer. Don´t forget to include a Diode to protect the MOSFETS from any inductive voltage spike to do so place a diode with its cathode connected to the MOSFET Drain and anode connected to GND.