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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It is likely neither one will work as-is. If limiting the voltage swing to turn it off works, maybe limiting the voltage swing to turn it back on would also work. CrossRoads on Jan 30, Hi, What is the load?
The following shows the conventional way to pull-up a PMOSFET’s gate in “c”and a theoretical way to speed it up irf495 mitigate wasted power in “e”: I’m still thinking about how to speed up turning Q5r back on. So, I came orf4905 with again, “c” is a “common” approach and “e3” is my latest irf49905 Mark, Tom, thank you both for your comments.
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, D5s is there to limit voltage at the gate to 10V, and R5s is there to ensure it doesn’t release too much magic smoke the shown value should keep it to around 0. Everything runs on smoke, let the smoke out, it stops running MarkT Brattain Member Posts: Commenting on variation “e” directly above: Yes you want this, but how do you switch it off?
Automotive PWM control of p-channel MOSFET (IRF) as high side switch
I’d be happy to hear of other or additional ways to minimize turn-off times while minimizing heat production from any components. I’ve come up with a couple of other ways to speed up turning off Q5rbut they were tending to get more complex than I’d like.
Gentlemen may prefer Blondes, but Real Men prefer Redheads! Perhaps a voltage divider which selects resistance to ground – likely through an “inverted” Q5b That’s why most people just use packaged solutions.
Q5r has most everything spec’d at a V GS of 10V, so I thought if we can keep the maximum voltage at the gate to something resembling that, it should be easier to drive it back to ground when we want it back on. MorganS Shannon Member Posts: The goal irf49055 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.
When the main transistor is off, its gate must be about 12V, so the source of Q5s is about 12V and Vgs now is going to be negative – the transistor is driven on hard. Krupski on Jan 30, However, making them too small incurs inefficiencies – and likely the resistors will produce too much heat themselves. One thing I can think that maybe should be included is a way to create a slight delay in Q5b turning off so Q5s can turn off Q5r a little “harder”?
We here have the orf4905 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 jrf4905. This has consequences though; when the PMOSFET is on, all current through the resistor is shunted to ground – which produces more current than wanted via that route, so I thought maybe increasing the resistance when the PMOSFET is on, and decreasing it when it’s off would mitigate that.
While I have experienced some glimmerings of understanding, I don’t know how far off I am with either the “5” or “3” circuits.
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. Lots of hints, allusions, partial answers, etc.
IRF4905 MOSFET. Datasheet pdf. Equivalent
Lots of interesting stuff there. TomGeorge on Jan 30, While I appreciate learning more about the hows and whys of doing things these ways, at the moment I just need to get it to work – preferably as efficiently as possible while itf4905 discrete component count to a dull roar.
Most of such devices cannot PWM, they take ‘s of us to switch. Without knowing as much as necessary or learning a ton of rif4905 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. MorganS on Jan 31, It’s a tad pricey, but if this becomes a 2-chip solution