Hardware-efficient programmable-deviation controller for indirect energy transfer DC-DC converters

In boost converters and other indirect energy transfer topologies, the fastest transient response usually does not coincide with the minimum possible output voltage deviation. This paper introduces a practical mixed-signal current programmed mode (CPM) controller that, compared to time-optimal solutions, provides a smaller deviation, lower current stress, and simpler controller implementation. To recover from transients, the controller passes through two phases. In the first phase, the inductor current is set in the proximity of its steady-state value, so that the initial transient-caused capacitor charging/discharging process is reversed. In the second phase, the voltage is gradually recovered. The controller implements a simple algorithm for setting up the inductor current and the output voltage peak/valley values during transients, based on the output current estimate, which is obtained through a self-tuning procedure. The operation of the controller is verified both through simulations and experimentally, with a boost-based 12 to 48 V, 100-W prototype, operating at 100-kHz switching frequency. A comparison with a time-optimal controller shows that the introduced programmable-deviation system results in up to 1.9 times smaller voltage deviation while limiting component stress.