A practical control strategy to improve unloading transient response performance for buck converters

DC-DC power converter with a modified control scheme to improve load transient response

“…In addition, the components values vary over time because of components aging and temperature variation effects during the power converter operation, which will also negatively impact the controller dynamic performance. All the aforementioned reasons are highly likely to cause undesired transient response as discussed in [6]. While in [6] it is assumed that the input voltage is constant, it is required to repeat the calculation process if the controller is to be used under a range of input voltage values.…”

“…However, this method depends on the accurate knowledge of the power converters' design parameters such as the inductance value and input voltage value because the controller operation depends on equations that are a function of component values that practically have error margin (component values tolerances), usually in the range of 5%-20%. Moreover, the controller operation in [6] is sensitive to calculations accuracy and rounding errors because rounding operations will most likely be required in the calculation of the number of auxiliary switching cycles [6] since it is rare that [6] is exactly equal to an integer, where n is the number of auxiliary switching cycles, in V is the input voltage of power converter, o V is the output voltage of power converter, o L is the main power stage inductance, and aux L is the auxiliary power circuit inductance. In addition, the components values vary over time because of components aging and temperature variation effects during the power converter operation, which will also negatively impact the controller dynamic performance.…”

“…A more simplified auxiliary circuit control method is presented in [6], the number of auxiliary switching cycles can be predicted in advance in order to achieve output voltage overshoot reduction. However, this method depends on the accurate knowledge of the power converters' design parameters such as the inductance value and input voltage value because the controller operation depends on equations that are a function of component values that practically have error margin (component values tolerances), usually in the range of 5%-20%.…”

Synchronous Buck converter with Output Impedance Correction Circuit

“…Solutions in [14]- [16] depend on the estimation of the amplitude of the load step based on the output voltage behavior which may lead to the unpredicted behavior of the system if the prediction is not performed correctly.…”

“…Similarly, in [7] the proposed circuit is injecting/extracting charge through auxiliary switches. Solutions from [14]- [16] utilize the auxiliary Boost converter in order to remove the additional charge from the output capacitor during the load step-down transient. The Synchronous Buck converter is used in [17] and [18] in a similar manner like the Boost from [14]- [16] for both load step-up and step-down transients.…”