When designing embedded microcontroller applications, one of the greatest challenges can be the creation of the power supply for the microcontroller; particularly when the only supply voltage available is significantly higher than the microcontroller’s maximum
VDD. To help simplify embedded design, Microchip has introduced a new feature in a select group of new microcontroller offerings: a 5V shunt regulator. This on-chip regulator allows the microcontroller to operate from a wide variety of supply voltages. As an added bonus, the shunt regulator topology also allows the connection of other circuitry, external to the microcontroller, to be powered by the VDD pin. This application note discusses the design of power supply circuits using the new shunt regulator, and presents some tips and tricks for extending the regulator’s capabilities.