We have a project where our 2nd year students build an H-bridge controller from scratch.  They learn a lot about power dissipation.  We have a simplified design using IRF540 for the N-channel, IRF9540 for the P channel.  These are way over-spec for the application, tiny robot motors.  WE use 6V batteries, so to turn on the gate of the N-channel transistors we can use the output of the Arduino, and to turn on the gate of the Pchannel we set gate to 0V, or leave in a high-Z state with a pullup resistor.

This works.  However, we were thinking of extending the exercise to show all N-channel.  That's the way it's done at larger scale because the N-channel has such dramatically better on-resistance.  I think the difference is 0.004 ohms vs. 0.113 ohms, so it's significant.  This would require that we generate Vcc + 5V for the gate.

For a teaching circuit, with a power side of 12V, is there a simple, clean way to generate a tiny current at a voltage 5V higher than Vcc?  We would like to have them build the circuit, not just use a black box.