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.
|Published (Last):||13 February 2008|
|PDF File Size:||11.95 Mb|
|ePub File Size:||2.36 Mb|
|Price:||Free* [*Free Regsitration Required]|
It’s a tad pricey, but if this becomes a 2-chip solution 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. Shutting it off is done via a pull-up resistor, and it seems that generally, the lower the resistance, the faster the PMOSFET will shut off.
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.
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”?
IRF – Infineon Technologies
Mark, Tom, thank you both for your comments. Now with Unlimited Eagle board sizes! Everything runs on smoke, let the smoke out, it stops running Hi, What is the load? Gentlemen may prefer Blondes, but Real Men prefer Redheads! 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.
What I know so far: MorganS Shannon Member Posts: I’ve also tentatively added in D5s and R5s. Some drivers do have an always-on charge-pump though, you’d have to search for the right part. Yes you want this, but how do you switch it off?
That’s why most people just use packaged solutions. 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.
IRF4905 MOSFET. Datasheet pdf. Equivalent
MarkT Brattain Member Posts: I’m still thinking about how to speed up turning Q5r igf4905 on. 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.
So, I came up with again, “c” is a “common” approach and “e3” is my latest incarnation: MarkT on Jan 30, While I have experienced some glimmerings of understanding, I don’t know how far off I am with either the “5” or “3” igf4905. 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.
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. I’m working on an automotive project which will use an Arduino as a controller. For this part, the requirements are: Most of such devices cannot PWM, they take ‘s of us to switch.
After a bit more stumbling around in the interwebs and learning tons more, I’ve come up with a simpler solution he says hopefully. TomGeorge on Jan 30, It is likely neither one will work as-is. 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. 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.
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. So, limit the lower voltage to something that will turn it irg4905 completely, and minimize the voltage swing necessary to shut it back off – maybe 1.
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. MorganS on Jan 31, Have you looked at purpose made Automotive High Side Switches? I don’t understand hardly any of “5”and have only partially figured out the push-pull arrangement in “3”so I’m not sure of any of the supporting components in either circuit missing, in excess, mis-valued, etc.
Perhaps a voltage divider which selects resistance to ground – likely through an “inverted” Q5b 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 interesting stuff there. If limiting the voltage swing to turn it off works, maybe limiting the voltage swing to turn it back on would also work.