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, elec- tronic air purifiers, emergency exit signs, and distrib- uted 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 applica- tions, 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 pro- vides a Constant Voltage output, the other a Constant Current output. AN216 DC/DC Converter Controller Using a PICmicro Microcontroller In any type of DC/DC Converter circuit, the power Author: Hartono Darmawaskita device selections are very important. The key parame- Microchip Technology Inc. ters to look for in the transistor Q1 are the switching time and current rating. These two parameters greatly affect the maximum switching frequency of the con- ……