Robust Adaptive Tuning of Digitally Controlled Switched-Mode Power Supplies

This paper presents an approach to continuous adaptive tuning of digitally controlled switched-mode power supply (SMPS) feedback loops. Tuning is performed via a multiple-input, multiple-output (MIMO) control loop that adjusts compensator parameters such that crossover frequency and phase margin measured by the digital controller match desired values. A design procedure for the adaptive tuning system is proposed which simplifies the small-signal MIMO design into two independent single-input, single-output (SISO) control loops. The adaptive tuning algorithm is further extended to account for large-signal changes from continuous conduction mode (CCM) to discontinuous conduction mode (DCM) and viceversa. Experimental results are given using an 11 V-to-5 V, 45 W, DCM/CCM buck converter as a test-bed.