Digital Charge Balance Controller to Improve the Loading/Unloading Transient Response of Buck Converters

A linear/nonlinear digital controller is presented that allows a Buck converter to recover from a load transient event with near-optimal voltage deviation and recovery time. A novel digital double accumulator calculation block is used to calculate the appropriate pulse width modulation switching time instants. The proposed controller possesses many advantages not demonstrated by a single controller in the previous literature. For example, unlike many previously proposed time-optimal digital controllers, the proposed controller provides an excellent transient response as it is capable of reacting asynchronously to a load transient event. In addition, it is demonstrated that the proposed controller can operate without requiring information pertaining to the Buck converter´s output inductor. Furthermore, the proposed controller can be extended to applications that require load-line regulation. Lastly, unlike all previous digital time-optimal controllers, the proposed controller does not require digital multiplier or divider blocks nor does it require 2-D lookup tables. Thus, the controller can be implemented through the use of low-cost field programmable gate arrays or complex programmable logic devices.