Reduced output topology for multi-reference switching amplifiers
A method and attendant circuitry reduces the number of regulatory and switching devices in a multi-reference switching amplifier. In the preferred embodiment, multiple independently-modulated effective references are summed at a load through use of both linear and switched control of switching devices.
1. In a multi-reference switching amplifier wherein switching devices control power supplied to a load in response to an input data stream having a sign, a simplified output topology, comprising:
first and second independently modulated references, wherein the second one of the references is derived through a voltage divider;
a data separator operative to separate the input data stream into course-resolution data and fine-resolution data;
circuitry for modulating the first one of the references on one side of the load as a function of the coarse-resolution data; and
circuitry for modulating second one of the references on the other side of the load as a function of the fine-resolution data.
2. The simplified output topology of claim 1 , wherein the first one of the references is supply rail.