Read the manual; PICAXE Manual 3: page 8- "Standard Circuits 4 - The Power MOSFET Interfacing Circuit". So, yes, of course you can do this. The main thing is to choose the appropriate MOSFET for the job. You need a "logic level" MOSFET, of which there are a limited number if you are looking for through-hole pinned chips; the choice is much wider if you can handle surface-mounted devices. If you are using pwm then you need to take care to choose an appropriate frequency/duty-cycle that is matched to the characteristics of the MOSFET (in terms of on/off times) to ensure that you do not have a heat problem. Without more parameters it is difficult for anyone to help you further.Hi guys i was wondering if it is possible to drive a power mosfet using the pwm pin on the PICAXE 20M2. Am designing a DC-DC converter, i dont know if is ok i use it?
In my experience a non-logic MOSFET will run hot and inefficiently.Thanks guys. Am using n channel power MOSFET (IRF510) to build a positive Buck-Boost converter. Am just going to try it and see how it works.
Just don't touch the MOSFET then, because driving the IRF510 with only 4 or 5 volts is going to make it real hot, real quick if you have any significant current through it at all. As was stated above, either use a logic-level gate drive MOSFET or use a driver circuit of some sort that will drive the MOSFET's gate with the appropriate turn-on voltage, which is closer to 10V than 5V.Thanks guys. Am using n channel power MOSFET (IRF510) to build a positive Buck-Boost converter. Am just going to try it and see how it works.
What does that have to do with driving an IRF510 with 4 to 5 Volts? That little letter "L" makes all the difference in the world.I'm driving a 200w car cooling fan with PWM on two IRL540's at 2Khz using a 14M2.
The MOSFET's don't even get warm.
Neil.
I built a full SMPSU using a 14M2. Variable voltage output of 0-35V (from a DC in of 36V) at 8A. I found that the problem wasn't the speed of the response of the PicAxe, more that the steps in the PWM were too large leading to the voltage wandering up and down by a few 100mV as it changed the pulse width in an attempt to regulate the supply. If you are not attempting such a wide range of regulation, this might be less of a problem.While the Picaxe PWM can certainly drive a power MOSFET , the IRF510 /Picaxe combination is an extremely poor choice for an SMPS. You will find it will run very hot if fail due to the heat. There are several reasons.
1. High "on resistance". At 540 milliohms with a 10V gate drive the IRF510 will get hot even with good driving driving parameters. It will be even worse with a 5V gate drive from a Picaxe
2. THE IRF 510 has a max gate threshold voltage of 4v. This is not a Logic Level FET. The threshold voltage is the voltage where the FET just beings to conduct, not the voltage where it operates ideally. This FET operates ideally with a 10V gate drive.
3. The Picaxe cannot enough peak current to turn this FET on quickly. While FETS are voltage controlled devices, they do have an input capacitance that needs to be overcome before turning on fully.
4. Generally speaking, a PICAXE cannot process the feedback signal fast enough for a stable control loop.