I'm using a visualization software in which I created an animated schematic for a part of the free charge controller:
http://everycircuit.com/circuit/4838391810097152
The entire schematic is here: http://1drv.ms/1AiMICL (or here)
Hopefully I have this set up right. I am questioning the purpose of C6 and C9. Why are they there? There doesn't seem to be current flowing between the terminals of C6 or C9. What is the main purpose of the induction coil?
I've worked on this now for a spot and I added the MOSFETs I am curious because in Every Circuit simulation there seems to be current flowing through M3 even though M3's gate is not powered at all in my simulation.
I thought that http://everycircuit.com/circuit/6539292895608832 is a good buck converter. It seems that a synchronous buck adds the use of another MOSFET which is used in an opposing configuration where one is on the other is always off and vice versa. That I understand. The power I see flowing in every circuit is just a small trickle at 16.7 mA however its making it through with nothing connected to M3's gate. I'm not sure how that's happening yet.
It seems to be the use of the ground that is causing the flow of current through MOSFET M3 even though the gate is off. Why is this happening?
Another question I have about this design is the MOSFET:
http://www.jameco.com/Jameco/Products/ProdDS/669943IR.pdf
Every Circuit software wants to know how many nm's or mm's is the mosfet. I don't know what Every Circuit is talking about yet.
Thank you
Best Answer
The circuit in the schematic is a power section of a Buck converter. Read-up on buck converters, because that's the background information that you might be missing.
M3 provides synchronous rectification, which is an improvement on the basic buck converter in efficiency and heat dissipation. As M3 is turned on and off, the current through M3 would be the same as if it were a diode. However, the turned on MOSFET doesn't have a forward voltage drop of a diode.