Word length selection method based on mixed simulation for digital PID controllers implemented in FPGA

Digital controllers implemented in an FPGA for switching power converters are becoming an important alternative to the traditional analog solutions. Assuming that the digital controller is described using a hardware description language (VHDL), the ADVance MS mixed-signal simulation tool is used to simulate in closed loop the digital controller in order to analyze the finite word-length effects. The use of the VHDL fixed point package in this procedure to select the word length may shorten the design cycle.