Parallel multiple MOSFETs using optimized current sharing technology
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- čas přidán 7. 08. 2024
- As presented at Electronica 2020
In High Power Applications, such as Motor Control, one MOSFET may not be enough - hence paralleling MOSFETs becomes a necessary solution. To achieve a reliable design that shares and stresses the devices equally, it is common to request semiconductor manufacturers to provide parts with matched threshold voltages. However, even with very tightly controlled production facilities there is an inevitable spread in the threshold voltage across the wafer. Any effort to provide matched Vth will require special screening and sorting that can result in yield loss, thus affecting the cost of the devices supplied. Nexperia have developed a new and unique MOSFET with improved current sharing capability when used in parallel which no longer relies on matched threshold voltages.
Presented by Stein Nesbakk, Application Engineer - Věda a technologie
Excellent presentation. Going from Bi-Polars to Mosfets has helped much with the temperature run-a-way problem, but I am glad to see that someone is working on the current sharing issue of Mosfets in parallel. Thanks for making this video.
so SSJ added codes are at current sharing technology family?
Hello! Products ending in J are our application specific MOSFETs for current sharing. The last 3 letters indicating package, gate threshold voltage and family. Example, PSMN2R3-100SSJ: LFPAK88, standard level, ASFET for current sharing.
Hi, good results, i often struggle parlleling MOS for dcdc
Is this current sharing MOS technology reducing somehow the efficiency(maybe higher rds on or other parasitics)? Can you make another video maybe showing a zoom in the transition, showing also vgs abd plateau zone ? Thanks
Hello, thanks for watching! This MOSFET technology is designed for switching inductive loads and specifically motor application to address current imbalances in paralleling MOSFETs. For DC/DC converters i.e. higher frequencies the same principle should apply. Great suggestion, we have many more videos coming this year regarding our current sharing technology. Subscribe to ensure you're notified when they're live.
@@Nexperia perfect
For dcdc we have similar needs of paralleling , due to heat diddipations especially if not heat sink is desired.e.g battery charger 400w automotive buck boost. already subscribed , thanks
Maybe a ferrite bead on the gate would suppress those oscillations at switch-on moment......
IN looking at sharing, and the discussion that things are 'inherently stable' for current sharing, because of rising Rds(on), that is for the case of a 'hard' turn-on, as in PWM operation, or? If used in any kind of linear mode, the threshhold voltage is an issue, no?
In the graphics for the PWM waveform, it would also be rather useful to show the driver waveforms into the gates?
Hello, thanks for watching! The intended application is switching i.e. hard turn ON/PWM, “inherently stable due to RDS(on) rising” refers to steady state and is a given regardless of which technology. This technology is specifically designed for dynamics during switching and resolves the current sharing instability normally caused by the different VGSth in MOSFETs. Pure linear mode operation is a different topic in itself.
Have an inverted welder which has 40N20 Yo7E mosfet .i cant find a replacement but have found smaller ones can I join 2? together???
Hello, 40N20 yo7E shows to be 200V, the current sharing technology devices are 80 and 100V. You can absolutely replace a bigger MOSFET with a smaller providing the spec is met. Here is an LFPAK56 devices with VDS of 200V and a similar capability: www.nexperia.com/products/mosfets/power-mosfets/PSMN059-150Y.html
When do expect to produce higher voltage devices that use your Current Sharing Technology? An example would be 200V.
Nexperia current-sharing technology is a first of its kind, it is implemented in the 80V and 100V platform devices as it is designed to primarily target motor control applications operating at nominal voltage range of 48V-60V. If you have specific requirements for higher voltages we'd love to discuss these, please contact us on nexperia.com/about/contact-us/
is there one for 1200v ? 36amps
Hello, these are 80/100V intended typically for 48V applications. Thanks!
Godd to know this current sharing technology but how about the on resistnce Rds ?
Hello! This technology was fine tuned to give best current sharing performance for dynamic switching. For steady state where RDSon is of relevance, the “MOSFET on-resistance” is a well-established parameter, usually with 98% - 99% of devices falling within typical values, combined with the fact that if there is any mismatch in current sharing, it is short lived and self-stabilise due to RDSon thermal characteristics and therefore does not cause major concern in switching application. Thanks!
Which devices have this feature?
Hello, for more information on current sharing MOSFETs please look to the Nexperia technology hub.
www.nexperia.com/technology-hub/industrial.html
So my 2000va ups has total of 12 N channel Mosfets. But in the board design there is place for 16 Mosfets, but for some reason they put 12.
So my question is can i add another 4 Mosfets in the empty place ?
Will it increase my ups efficiency (not backup time's) and lasts longer.
Will it be Dangerous, i mean adding additional 4 mosfet will burn my PCB ?
Plz answer Sir.
Hello, thanks for your question! Your UPS vendor will have left spaces because 12 were sufficient for the output load (space for the extra four MOSFETs is for future expansion or higher power output), so in short yes, you can add 4 MOSFETs in the empty spaces. It all depends how you define efficiency, if a design meets all the requirements with 12 MOSFETs then using 16 it is not efficient in terms of cost, but using 16 instead of 12 it will reduce power dissipation and may make the design last longer. Adding more MOSFETs will reduce power dissipation and reduces heat.
@@Nexperia Thank you for replying. Actually my ups board Mosfets got blown off without any kind of load a week ago. It was charging that time..so i need to change all the Mosfets. Then i saw 12 instead of 16 and i can buy those SW3205 Mosfets in a very low price. So if i add another 4 do i need to add any sort of capacitor/resistor/diods/whatever ?
If you want i can send you my board picture if you give me an email address.
Hello, please get into contact here and we will support as best we can www.nexperia.com/support/