US 10,476,444 B1 · Cross-fading in dual-path pulse width modulation system

Abstract

A system may include a plurality of playback paths comprising an open-loop playback path configured to drive an output load and a closed-loop playback path. The closed-loop playback path may include an outer feedback loop comprising one or more integrators, a quantizer, and an output driver for driving the output load, the outer feedback loop having an outer loop feedback gain and an inner feedback loop comprising the one or more integrators and the quantizer and excluding the output driver, wherein the inner feedback loop has a variable inner loop feedback gain which is adjustable to match the outer loop feedback gain.

Claims20

Dependent claims

A system comprising a plurality of playback paths, the playback paths comprising:

an open-loop playback path configured to drive an output load;
and
a closed-loop playback path comprising:
an outer feedback loop comprising one or more integrators, a quantizer, and an output driver for driving the output load, the outer feedback loop having an outer loop feedback gain;
and
an inner feedback loop comprising the one or more integrators and the quantizer and excluding the output driver, wherein the inner feedback loop has a variable inner loop feedback gain which is adjustable to match the outer loop feedback gain.

3 more elements

A system comprising:

a plurality of playback paths, the playback paths comprising:
an open-loop playback path configured to drive an output load;
and
a closed-loop playback path configured to drive the output load;
and
a control subsystem configured to select between the open-loop playback path and the closed-loop playback path to drive the output load and further configured to, in response to a condition for switching selection between the open-loop playback path and the closed-loop playback path, cross fade between the open-loop playback path and the closed-loop playback path by, during a duration of the cross fade:
for each of a plurality of sets of pulse-width modulation periods for an output signal driven to the output load, switching in a deterministic pattern between the open-loop playback path and the closed-loop playback path;
and
for successive sets of the pulse-width modulation periods during the duration, an incidence of selection of a first of the open-loop playback path and the closed-loop playback path increasing and an incidence of selection of a second of the open-loop playback path and the closed-loop playback path decreasing.

6 more elements

A method comprising, in a system comprising a plurality of playback paths comprising an open-loop playback path configured to drive an output load and a closed-loop playback path configured to drive the output load:

selecting between the open-loop playback path and the closed-loop playback path to drive the output load;
and
in response to a condition for switching selection between the open-loop playback path and the closed-loop playback path, cross fading between the open-loop playback path and the closed-loop playback path by, during a duration of the cross fade:
for each of a plurality of sets of pulse-width modulation periods for an output signal driven to the output load, switching in a deterministic pattern between the open-loop playback path and the closed-loop playback path;
and
for successive sets of the pulse-width modulation periods during the duration, an incidence of selection of a first of the open-loop playback path and the closed-loop playback path increasing and an incidence of selection of a second of the open-loop playback path and the closed-loop playback path decreasing.

3 more elements

Dependencies are inferred from the claim text.

Cross-fading in dual-path pulse width modulation system

Life of this patent

Cross-fading in dual-path pulse width modulation system

Life of this patent

Abstract

Claims20