Driving and protection of high side NMOS power switches

The design of a full-wave voltage-tripler charge pump for driving high-side NMOS switches that can operate with supply voltage variations from 5 to 50 V is described. The circuits for both simple and complex charge pumps and their limitations are discussed. It is shown that the power switch must be protected from external as well as internal voltages. Described are the protection circuits that are necessary to ensure that the working voltage of the control devices and power switch are not exceeded, particularly when working with inductive loads and against supply line transients.<>