I have an application with some constraints for which it feels difficult to find a solution.

  1. load current more than 10A, so N channel MOSFET is preferred;

  2. working voltage is a bit high, between 50-80V;

  3. logic switch control signal, no driving capability while expecting very fast response;

  4. due to some reason, high side switching is required. That is, the MOSFET will be between power source and load. The load is non-inductive like one in buck converter.

I have searched the web for high-side MOSFET driver, but all are with buck type of application, coming with external capacitor connected to source of MOSFET to get ground rail to be charged. Which I don't think it works in my application where no ground rail exists after switch-on.

I found few drivers with charge pump built-in, but below 36V.

I know a workaround that uses a battery and connects the negative of the battery to source of MOSFET, but this is not a solution as I have no way to charge the battery and so it has to be replaced regularly.

  • \$\begingroup\$ MAXIM makes an isolated Power Converter, using a transformer. \$\endgroup\$ Commented May 13, 2017 at 11:51
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    \$\begingroup\$ There are plenty of P-channel MOSFETS that will happily drive a 10A load. The problem with using an N-channel as a hight side switch is that you need a gate voltage higher than the voltage you're switching. See this question Switching DC with MOSFET: p-Channel or n-Channel; Low Side Load or High Side Load? for a full explanation. \$\endgroup\$
    – Finbarr
    Commented May 13, 2017 at 11:53
  • 1
    \$\begingroup\$ I use IR LEDs to drive n-chans when I need a higher Vgd than handy... \$\endgroup\$
    – dandavis
    Commented May 13, 2017 at 12:01
  • \$\begingroup\$ @dandavis How would you do that? Without further explanation, your comment is unlikely to help anyone ;) \$\endgroup\$
    – marcelm
    Commented May 14, 2017 at 10:08
  • 1
    \$\begingroup\$ a bright white led shining directly into a red led will cause to red LED to output ~1.5v. connecting them in series adds voltage. Alternating flat LEDs are very easy to wire in series into a compact light target. Shunt a 1-10m GS bleeder to drive MOSFETS. \$\endgroup\$
    – dandavis
    Commented May 14, 2017 at 16:55

3 Answers 3


If the application permits, you can use an isolated power supply (12V or 15V) to create the gate driver voltage, then use an optocoupler to turn MOSFET ON or off.

You could use a photovoltaic MOSFET driver (usually used for SSR) For example the VOM1271: VOM1271

Use a automotive high side switch (it contains MOSFET and driver protection features and diagnosis), search Infineon and ST, but honestly it might be difficult to find one that works at 80V Another example: smart high side switches

  • \$\begingroup\$ Thank you for reply. VOM1271 looks decent solution, only it is too slow in my application. I will expect a switch off within few hundreds nano seconds. it is a surge voltage protection switch (with a comparator). For high side switch module, it might be too expensive.. \$\endgroup\$
    – Spark
    Commented May 16, 2017 at 4:37
  • \$\begingroup\$ The turn on is slow , but the turn off is fast relatively , (check figure 5 in the datasheet ) . It contains a turn off Jfet internally . regarding the price , it is probably expensive for such application \$\endgroup\$
    – Sarah
    Commented May 16, 2017 at 16:24

The newish LTC7001 allows this functionality however comes in an annoying package.


You say that because 10A of current is to be switched, N-channel is to be preferred. I don't see why. There are quite a few P-channel MOSFEts that can fulfill your requirements, as this search on DigiKey shows.

Just as an example, take the following model, taken from that list:

enter image description here

  • 1
    \$\begingroup\$ This, except make sure you're inside the part's SOA. \$\endgroup\$
    – Matt Young
    Commented May 13, 2017 at 23:24
  • \$\begingroup\$ @Matt young. there are some reasons for n channel to be preferred. 1. n channel usually has lower on resistance than P channel, since the switch will be always on during load working to dissipate power (and voltage drop as well) with high working current. 2. p channel has less choices on market than n channel, usually more expensive. \$\endgroup\$
    – Spark
    Commented May 16, 2017 at 4:52
  • \$\begingroup\$ @Spark Ok, for n.2 (but you must also weigh in the cost for your high-side N-channel mosfet gate driver). For n.1 you should consider your design target. .... \$\endgroup\$ Commented May 16, 2017 at 13:36
  • \$\begingroup\$ @Spark ... If you want the absolutely lowest Rds(on) you'll need N-channel, but if a given P-channel MOSFET meets your goals AND it simplifies your design, you could be better off with the latter. BTW, since we are talking about switching applications, you could also parallel devices: not only this lowers equivalent Rds(on), but it increases current handling capability and helps spreading the heat dissipation among multiple devices, which in turn could make your thermal design easier. \$\endgroup\$ Commented May 16, 2017 at 13:36
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    \$\begingroup\$ With 200mΩ RDSon you're going to be dissipating 20W at 10A. That's like having half a soldering iron on your board. \$\endgroup\$
    – jcoffland
    Commented Jul 23, 2020 at 5:32

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