Or a nice chip that does something like this one... http://www.ti.com/lit/ds/symlink/tps2032.pdf http://www.ti.com/lit/ds/symlink/tps2032.pdf N Channel (more e

Or a nice chip that does something like this one... http://www.ti.com/lit/ds/symlink/tps2032.pdf http://www.ti.com/lit/ds/symlink/tps2032.pdf N Channel (more efficient than P channel) with integrated charge pump for the gate driver.