Pulse-width modulated (PWM) audio power amplifier with output transition slope control

摘要

An audio switching power amplifier having an output with controlled-slope transitions maintains efficiency while avoiding uncontrolled non-overlap intervals during switching transitions. A pair of transistors forming a half-bridge that supplies an output signal at an output terminal of the amplifier are operated so that neither transistor is fully on during an overlap time period. A current source provides an output current to the output terminal during the non-overlap time period to control the output voltage while changing the transistor that conducts the output current from a first one of the pair of transistors to a second one of the pair of transistors. The current source may be provided by operation of one of the transistors in a current source configuration. The voltage of a gate of one of the transistors can be compared with a threshold to provide an indication of the current.

主权项

1. A switched-power circuit, comprising:
a switching output stage comprising a pair of transistors coupled in a half-bridge configuration and having an output terminal at their common connection; a switching control circuit for controlling the switching output stage, wherein the switching control circuit controls the switching output stage such that neither of the transistors of the pair are biased fully on during a non-overlap time period; and a current source for providing an output current to the output terminal during the non-overlap time period to control changes in an output voltage at the output terminal while changing the transistor that conducts the output current from a first one of the pair of transistors to a second one of the pair of transistors.