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Power mosfet to drive high side of the load. Does it exist?

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autotel:
In short
I did a simulation in the Falstad circuit simulator. I know that components there might be ideal, but I am looking for the closest version of it. The link is at the bottom. Basically it would be a MOSFET that gets triggered with ~1 volt in comparison to the source, and can source high voltage from the drain.

The context is this: I want to drive the high side of an inductive load (different motors & solenoids) using a microcontroller. I want to make it compatible with a wide range of loads, and I want to use few, easily found parts.

Side notes

I noted that by having a higher "beta" value, the transistor in the simulation let's more current. I guess that beta is the slope "angle" of the Vgs/Ids line in the graph. I could find some N type power Mosfets with these characteristics. The thing that doesn't fit in my mind, is that a TIP120, which is what I was using before, did not work as a high-side switch, hence, the tip120 has something different than the transistor in the simulation.

Additionally, I visited Gammon's blog, and he shows how to drive the high side of a load, and it requires many components beside the N type MOSFET. I find the same being said in many other places. However, I am pretty sure there have to be components that integrate all the part Gammon is suggesting to add as a high-side switch, in an enclosed package. Furthermore, according to various electronic books/ articles, the idea of a transistor is to let power flow between drain and source, when gate has a voltage.

Should I keep looking for generic parts (and which?) or should I go for a proprietary load controller, such as those from Pololu?

Link
(I didn't shorten it so that it doesn't break later)
http://www.falstad.com/circuit/circuitjs.html?cct=$+1+0.000005+10.20027730826997+50+5+50%0Af+304+240+352+240+32+1.5+1000%0A172+224+240+192+240+0+7+2+20+0+0+0.5+Gate+Voltage%0Aw+352+256+352+304+0%0Aw+352+224+352+176+1%0A172+352+176+352+144+0+7+12+12+0+0+0.5+Drain+Voltage%0Ag+352+384+352+400+0%0Al+272+304+272+384+0+1+0%0As+224+240+304+240+0+0+false%0Ac+480+304+480+384+0+1+0.2029133990689438%0Ad+400+384+400+304+2+default%0Aw+352+384+400+384+0%0Aw+400+304+352+304+0%0Ar+352+304+352+384+0+0.2%0Ao+0+64+0+4099+20+3.2+0+2+0+3%0Ao+6+64+0+4097+5+0.00009765625+1+2+6+3%0A38+0+1+1+1000+%3Ca%5Cshref%5Cq%22mosfet-beta.html%22%5Cstarget%5Cq%22_blank%22%3EBeta%3C/a%3E%0A

Mechatrommer:
Look for high side mosfet driver ic, simplify alot of component esp charge pump. or just use p channel mosfet

garethw:
P-Channel MOSFETs are easier to implement but typically have higher RDSon values which basically means they have a higher resistance when fully conducting.
Using a charge pump design enables the use of more efficient N-Channel devices but requires more components.


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Zero999:

--- Quote from: autotel on June 26, 2019, 07:59:07 am ---In short
I did a simulation in the Falstad circuit simulator. I know that components there might be ideal, but I am looking for the closest version of it. The link is at the bottom. Basically it would be a MOSFET that gets triggered with ~1 volt in comparison to the source, and can source high voltage from the drain.

The context is this: I want to drive the high side of an inductive load (different motors & solenoids) using a microcontroller. I want to make it compatible with a wide range of loads, and I want to use few, easily found parts.

Side notes

I noted that by having a higher "beta" value, the transistor in the simulation let's more current. I guess that beta is the slope "angle" of the Vgs/Ids line in the graph. I could find some N type power Mosfets with these characteristics. The thing that doesn't fit in my mind, is that a TIP120, which is what I was using before, did not work as a high-side switch, hence, the tip120 has something different than the transistor in the simulation.

Additionally, I visited Gammon's blog, and he shows how to drive the high side of a load, and it requires many components beside the N type MOSFET. I find the same being said in many other places. However, I am pretty sure there have to be components that integrate all the part Gammon is suggesting to add as a high-side switch, in an enclosed package. Furthermore, according to various electronic books/ articles, the idea of a transistor is to let power flow between drain and source, when gate has a voltage.

Should I keep looking for generic parts (and which?) or should I go for a proprietary load controller, such as those from Pololu?

Link
(I didn't shorten it so that it doesn't break later)
http://www.falstad.com/circuit/circuitjs.html?cct=$+1+0.000005+10.20027730826997+50+5+50%0Af+304+240+352+240+32+1.5+1000%0A172+224+240+192+240+0+7+2+20+0+0+0.5+Gate+Voltage%0Aw+352+256+352+304+0%0Aw+352+224+352+176+1%0A172+352+176+352+144+0+7+12+12+0+0+0.5+Drain+Voltage%0Ag+352+384+352+400+0%0Al+272+304+272+384+0+1+0%0As+224+240+304+240+0+0+false%0Ac+480+304+480+384+0+1+0.2029133990689438%0Ad+400+384+400+304+2+default%0Aw+352+384+400+384+0%0Aw+400+304+352+304+0%0Ar+352+304+352+384+0+0.2%0Ao+0+64+0+4099+20+3.2+0+2+0+3%0Ao+6+64+0+4097+5+0.00009765625+1+2+6+3%0A38+0+1+1+1000+%3Ca%5Cshref%5Cq%22mosfet-beta.html%22%5Cstarget%5Cq%22_blank%22%3EBeta%3C/a%3E%0A

--- End quote ---
That circuit is a source follower. The voltage on the output will always be lower than the gate, by the threshold voltage.

As mentioned above, the gate voltage needs to be boosted above the positive supply voltage to fully turn the transistor on. A P-channel device could be used but they have a much higher on resistance, with everything else being equal.

Mechatrommer:
Yeah i heard that alot.. when nfet is say 14mohm, its complimentary pfet is 28mohm give or take. How bad can it be?  Before mosfet age, people used power bjt which is alot more mediocre. But when that extra 14mohm matters esp in very high current app, then the best is nfet w hi side driver no doubt.

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