Mosfet Driver and mosfet combo? Why not combine both to get a compact design?

Thread Starter

Matterh

Joined Nov 24, 2019
5
Is there a category for a device that has the mosfet drive and power mosfet in the same package? Obviously it will need pins VCC, GND, Source, Drain, input (Gate not required if it is a combined device!)

The disadvantage is not being able to control the switching using caps and resistors. But for small applications where you want a tiny DC to DC converter (as an example) it doesnt matter.

I am trying to make a extremely compacted high power density device. At the moment i have so many parts... I have a mosfet, mosfet driver, inductor, capacitors, diode.

Why have a mosfet driver plus a power mosfet for small applications? Surly there is a combo integrated device?

I have had to use a mosfet driver because the signal input is not strong enough to switch the mosfets gate, seriously affects the on/off times producing heat in the power mosfet which reducing the power density.
 

Papabravo

Joined Feb 24, 2006
12,766
The reason that such a part will never be available is that MOSFETs come in such a wide variety of characteristics that you would need to make every MOSFET with a driver and that would raise the cost for everybody that does not need one.
 

Thread Starter

Matterh

Joined Nov 24, 2019
5
The reason that such a part will never be available is that MOSFETs come in such a wide variety of characteristics that you would need to make every MOSFET with a driver and that would raise the cost for everybody that does not need one.
While I agree on the variety of characteristics I disagree that it would add cost to small applications. LM2596 is a great example of a compact design reducing cost and complexity.

Even with a small and powerful mosfet, the gate charge is generally still too high for IO pins and requires a mosfet driver for high frequencies, not to mention the IO voltage is generally not high enough to exceed the miller charge region.

Maybe i am trying to bake a cake and eat it too. Maybe its wishful thinking. I thought it might be quicker to ask the internets if such a category exists, or maybe its right infront of me and im not aware of it.
 

jpanhalt

Joined Jan 18, 2008
8,439
Actually, I believe such combinations are available. Their development seems to have been driven by the automotive industry and there are lots of choices. Here is one from my files that is now "obsolete": https://www.infinite-electronic.hk/datasheet/bf-VN340SP.pdf

One will generally find them if you search for "smart" switches. For example, search for, "Infineon Smart High-side Switch." I have attached a booklet from Infineon. Unfortunately, I had to upload it as I could not find it on the current Infineon site and failed to record the link at the time (which probably wouldn't work anyway).
 

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Papabravo

Joined Feb 24, 2006
12,766
I never said or implied that it was technically impossible, only that for economic reasons that it was commercially infeasible; and thus unlikely to appear, or if it did appear unlikely to persist.
 

jpanhalt

Joined Jan 18, 2008
8,439
I never said or implied that it was technically impossible, only that for economic reasons that it was commercially infeasible; and thus unlikely to appear, or if it did appear unlikely to persist.
Nor did I imply that. You did say it would never be available.

Infineon and others seem to have found at least a niche in the automotive and other markets and have been producing such devices for at least 10 years. Whether that is "persistence" in a field like solid-state electronics is not worth debating. Infineon itself was spun off from Siemens in 1999 and has 41,000 employees. It seems to be doing something right.
 

Papabravo

Joined Feb 24, 2006
12,766
Nor did I imply that. You did say it would never be available.

Infineon and others seem to have found at least a niche in the automotive and other markets and have been producing such devices for at least 10 years. Whether that is "persistence" in a field like solid-state electronics is not worth debating. Infineon itself was spun off from Siemens in 1999 and has 41,000 employees. It seems to be doing something right.
Except they have a tendency to renege on orders placed with long lead times if it suits them.
 
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