In many applications, a DC/DC Converter is used to produce a regulated voltage or current, derived from an unregulated power supply, or from a battery. Examples of these applications include battery chargers, electronic air purifiers, emergency exit signs, and distributed power systems.
In some of those applications, a dedicated Switched Mode Power Supply (SMPS) Controller IC is used in conjunction with a microcontroller. In other applications, however, a dedicated SMPS Controller IC may be overkill. An alternative approach is to generate a low cost SMPS function in a smart microcontroller, such as the PIC16C620A. This Application Note shows a method of using the microcontroller to perform simple SMPS control functions. Two circuits were built for evaluation. One circuit provides a Constant Voltage output, the other a Constant Current output