Implementation of digital PID controllers for DC-DC converters using digital signal processors

Implementation of digital PID controllers for DC-DC converters is discussed in this paper. The primary advantages of digital control over analog control are higher immunity to environmental changes such as temperature and aging of components, increased flexibility by changing the software, more advanced control techniques and reduced number of components. Analog PID and PI controllers were first designed using frequency response techniques, then converted into digital controllers. Digital PID and PI controllers are then implemented using digital signal processors (DSPs). Two possible choices of DSPs are introduced. The first one is the TMS320F2812 DSP from Texas Instrument, and the second one is the Si8250 digital power controller from silicon laboratories. Main features and development tools for both DSPs are introduced. Digital PID and PI controllers were implemented on the TI TMS320F2812 DSP. Experimental results for a prototype buck converter are presented.