Fine resolution pulse width modulation pulse generator for use in a multiphase pulse width modulated voltage regulator

摘要

Disclosed is a fine resolution pulse width generator for use in a multiphase pulse width modulated voltage regulator. The fine pulse width is generated by first generating a pulse with a coarse pulse width and one or more delayed replicas thereof. Then, digitally controlled analog interpolators are used to generate the fine resolution pulse width pulse by interpolating among the coarse pulse width pulses. Both single edge and double edge modulation embodiments are disclosed providing interpolation of just the trailing edges of the coarse pulses or both the leading and trailing edges, respectively. The disclosed fine resolution pulse generator uses counters, thermometer encoders and analog interpolators to achieve interpolation accurately by insuring that each interpolation step corresponds to an equal weight. Accuracy of the interpolation is defined by the linearity (i.e. how well the interpolation fits a best fit straight line) and monotonicity (i.e. how each step contributes a positive weight to the total).