MULTIPLE SWITCH POWER STAGE CONTROL TRACKING PCM SIGNAL INPUT

摘要

A DC power stage provides a power output that tracks a PCM signal input. A mapping unit generates an integer number of N digital PWM signals each switched at a same switching frequency by switching states of the PWM signals one at a time based on a level of the PCM signal input. An imbalance correction unit adjusts a duty ratio of the PWM signals relative to one another based on differentially accumulating errors among the PWM signals to prevent divergence of PWM signals. N corresponding switches therefrom switch power from a DC power source. N inductances in parallel produce a combined signal that is low pass filtered to provide the power output. Switching is between only those state combinations where the switching frequency is cancelled in the combined signal. The switching frequency is a sampling frequency of the PCM signal input divided by a product of 2 times N.

主权项

1. A DC power stage for providing a power output that tracks a PCM signal input, comprising:
a mapping unit for generating an integer number of N digital PWM signals each switched at a same switching frequency by switching states of the N digital PWM signals one at a time based on a level of the PCM signal input; an imbalance correction unit operatively coupled to the mapping unit to adjust a duty ratio of the N digital PWM signals relative to one another based on differentially accumulating errors among the N digital PWM signals to prevent divergence of N digital PWM signals and produce N balanced digital PWM signals; N switches each operatively coupled to a corresponding one of the N digital balanced PWM signals from the imbalance correction unit to switch power from a DC power source based on the corresponding one of N balanced digital PWM signals; N inductances in parallel, each of the N inductances operatively coupled to a corresponding one of the N switches to produce a combined signal; and a low pass filter operatively coupled to filter the combined signal from the N inductors and provide the power output tracking the PCM signal input.