Analog adaptive current injected control of DC-DC switching converters with robust dynamic response

Like any other fixed regulator analog control scheme, the small signal bandwidth of current mode controlled power converters is affected by changes in the line voltage, the load and the passive components of the power stage. The same applies to the disturbance rejection dynamic properties of the loop, i.e., closed loop output impedance (load disturbance) and audiosusceptibility (line disturbance). Model reference based control is an analog approach to adaptive control that can be easily implemented and can also reduce the sensitivity of power converter dynamics to the changes mentioned above. Based on that principle a 5 V-5 A, 50 kHz Buck prototype operating from an input voltage ranging from 25 V to 15 V has been tested with different LC filters and load conditions, including discontinuous conduction mode. The empirical large signal response of the power converter, under load and reference voltage steps, is shown in this paper, validating the concept.