International Rectifier / Infineon IRF MOSFET are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for International Rectifier. IRF Transistor Datasheet, IRF Equivalent, PDF Data Sheets. MOSFET. Parameters and Characteristics. Electronic Component Catalog. 25 Aug Е Uses IRF data and test conditions. Source-Drain Ratings and Characteristics. Parameter. Min. Typ. Max. Units. Conditions. V(BR)DSS.
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You will have to draw a LOT of current through Q5b before you can get Q5s down to a voltage where you can switch it off. MarkT on Jan 30, It’s a tad pricey, but if this becomes a 2-chip solution Lots of hints, allusions, partial answers, etc. That’s why most people just use packaged solutions. Now with Unlimited Orf4905 board sizes!
I’ve done some more thinking, and have come up with something else; no idea if it’d work, but what the heck, throw it out there jrf4905 see what sticks. I’m working on an automotive project which will use an Arduino as a controller. So, limit the lower voltage to something that will turn it on completely, and minimize the voltage swing necessary to shut it back off – maybe 1.
So, I came up with again, “c” is a “common” approach and “e3” is my latest incarnation: MorganS on Jan 31, We here have the problem that there is only an unclean 12V supply to work with, with spikes and dips, and standard high-side drivers for n-MOSFETs need clean stable 12V to work with. However, when it’s on, most current is routed through this resistor, so heat becomes a concern.
Krupski on Jan 30, I’m still thinking about how to speed up turning Q5r back on.
Shutting it orf4905 is done via a pull-up resistor, and it seems that generally, the lower the resistance, the faster the PMOSFET will shut off. Mark, Tom, thank you both for your comments.
Most of such devices cannot PWM, they take ‘s of us to switch. Commenting on variation “e” directly above: For this part, the requirements are: To mitigate this heat production, reductions in switching times are required; here are two discrete-component approaches which I’ve cobbled together from suggestions and circuits I’ve found in various places: A simple voltage doubler circruit can be built to pump up a small capacitor to about 24V, then that can be dumped into the P MOSFET with an N-type at the appropriate time.
It can drive 6,pF in 40ns at 6A. TomGeorge on Jan 30, Some drivers do have an always-on charge-pump though, you’d have to search for the right part. Everything runs on smoke, let the smoke out, it stops running Gentlemen may prefer Blondes, but Real Men prefer Redheads!
irf49905 I did a Google search on these forums which produced a lot of topics on this; I’ve read every one of them and even started my own. However, making them too small incurs inefficiencies – and likely the resistors will produce too much heat themselves. While I have experienced some glimmerings of understanding, I don’t know how far off I am with either the “5” or “3” circuits.
One thing I can think that maybe should be included is a way to create a slight delay in Irf49005 turning off so Q5s can turn off Q5r a little “harder”? Lots of interesting stuff there.
IRF4905 MOSFET. Datasheet pdf. Equivalent
I’m aware that the specified components may not be optimal and there are likely support components missing, but this is just to see if this could work in theory. TomGeorge Design and Repair of industrial control systems. I’d be happy to hear of other or additional ways to minimize turn-off times while minimizing heat production from any components.
Without knowing as much as necessary or learning a ton of the calcs required to make complete sense of everything, I’ve read lots on this here and elsewhere and have not been able to find any complete answers.
IRF – Infineon Technologies
I’ve also tentatively added in D5s and R5s. CrossRoads on Jan 30, After a bit more stumbling around in the interwebs and learning tons more, I’ve come up with a simpler solution he says hopefully. The goal at the moment is to minimize R5r as much as Q5r will allow; its value was selected to drive about 2A into Q5r ‘s gate when Q5r is to be off, and when we want Q5r on, maximize the efficiency of the path to ground.
What If4905 know so far: