Average Current Mode Controlled Power Factor Correction Converter..TMS320LF2407A (Rev. A)

Low cost, high performance DSP controllers with integrated peripherals such as, analog-to-digital (A/D) converters and pulse width modulator (PWM), have enabled the power supply designers with a new tool for implementing control for their power conversion functions. However, the power designers with mostly analog control experience are faced with new challenges as they start to adopt this new technology and make transition from the existing analog space to its new digital environment.

This application report identifies some of the basic differences between the two approaches and shows a step-by-step implementation of a DSP controlled average current mode power factor correction (PFC) converter. Different control loop parameters in the analog control space are redefined prior to their digital implementation. The loop is analyzed and the required voltage and current loop compensators are derived. Finally, the discretization of these compensators and their implementation in software are also presented.