The digest proposes a digital estimator based control method in point-of-load (PoL) DC-DC converters to achieve fast response times and minimum voltage deviation under frequent load transients. Using the proposed method, a fast digital controller can be designed even without prior knowledge of various delays in the control loop. It is particularly effective while operating at higher switching frequencies when the delays are comparable or even may be greater than the switching period. Moreover, an instantaneous estimator based response for load transients can significantly reduce the output voltage deviation, which can further reduce the size of the filter capacitor. The approach is experimentally verified on a GaN based synchronous buck converter prototype. Experimental results are shown for load transients from 1 A to 7 A and back at Vo = 30 V and Vg = 80 V, with output voltage deviation less than 1.5V and response times in the range of 5 − 6 μs using the proposed approach.
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