A novel digital capacitor charge balance control algorithm with a practical extreme voltage detector

Dc-dc Buck converter has a major application for powering integrated circuit under stringent regulation, nowadays. In this paper, a practical digital control algorithm is presented to achieve the optimal response for dc-dc Buck converters without relying on the knowledge of the passive component value (inductance and capacitance). This algorithm introduces the curve fitting analysis for deriving the formulas to optimize the response under different transients from input voltage and load current. An opportunity is also provided for adaptive voltage positioning (AVP) technique under load transients without significant modifications on the original algorithm. Furthermore, an operational amplifier (OPAMP) based peak/valley voltage detector is introduced in place of using a fast or asynchronous ADC, upon which an improved performance and design simplicity can be expected on the entire digital control system. The estimation error of the proposed scheme is simulated and illustrated to provide a design guideline. Finally, simulation and experimental results are provided to validate the proposed schemes.