MCP1407 should be delivered to me tomorrow so I’ll try with my existing MOSFETs first. Will I need any resistor, diodes? My local store should have these things.
I suggest the following:
- A good decoupling capacitor between the Vdd and Gnd terminals of the MCP1407. I suggest 1uF ceramic.
- A 10K resistor between the MCP1407 input and ground. This is to ensure that the MCP1407 (and hence the mosfet) stays off until the Arduino output pin mode has been set.
- A resistor between the MCP1407 output and the mosfet gate, to limit the peak gate current and control ringing if your layout is less than ideal. I suggest 10 ohms, perhaps less if/when you use fast PWM. If you have a singls MCP1407 driving 2 mosfets, use a separate resistor for each mosfet.
You should position the MCP1407 close to the mosfet(s), so that the wiring (in particular the wire between the mosfet source terminal and MCP1407 Gnd) is kept as short as reasonably possible.
When I asked what is better for me I probably meant what is easier, but reliable at the same time.
I suggest you start with simple on/off control then. You can upgrade to smoothed PWM later.
The driver has arrived today, much later than expected, and on top of that my local store don’t have any capacitors or resistors…
I’m off tomorrow so I’ll be on a mission… only if I knew I would have ordered it online already. Anyways…
dc42, when you say decoupling capacitor 1uF ceramic, do you mean 1000nF or 0.1uF/100nF? My local store only have 0.1uF in their catalogue, but the guy said they’re out of stock. However their website says they have plenty.
Is any of these caps any good? http://www.maplin.co.uk/decoupling-ceramic-disc-capacitors-318
I will be visiting my local RS Components branch http://uk.rs-online.com/web/ to get all this, but I am having difficulties finding 1uF decoupling capacitor there too.
I’ve done my best with the fritzing diagram. I think I need to learn it more :]
PWM control.fzz (24.3 KB)