Loudspeaker driver systems
AssigneeCirrus Logic, Inc.
InventorJohn P. Lesso
Life of this patent
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Abstract
A system for driving a loudspeaker having a plurality of coils, the system comprising: a modulator configured to receive an input signal and to output a pulse width modulated (PWM) output signal representative of the received input signal; a delay element for receiving and applying a delay to the PWM output signal to generate a first delayed signal; a first output configured to be coupled to a first coil of the plurality of coils of the loudspeaker, wherein the first output is coupled to the output of the modulator; and a second output configured to be coupled to a second coil of the plurality of coils of the loudspeaker, wherein the second output is coupled to the output of the delay.
Claims21
A system for driving a loudspeaker having a plurality of coils, the system comprising:
- a modulator configured to receive an input signal and to output a pulse width modulated (PWM) output signal representative of the received input signal;
- a delay element for receiving and applying a delay to the PWM output signal to generate a first delayed signal, the delay element comprising a clocked buffer or a counter;
- a first output configured to be coupled to a first coil of the plurality of coils of the loudspeaker, wherein the first output is coupled to the output of the modulator;
- and
- a second output configured to be coupled to a second coil of the plurality of coils of the loudspeaker, wherein the second output is coupled to the output of the delay element;
- wherein the modulator and the delay element are configured to receive a clock signal.
A method for driving a loudspeaker having a plurality of coils, the method comprising:
- receiving, at a modulator, a clock signal and an input signal and outputting a pulse width modulated (PWM) output signal representative of the received input signal;
- and
- applying a delay to the PWM output signal using a delay element that comprises a clocked buffer or a counter that receives the clock signal to generate a first delayed signal;
- outputting the PWM modulated output signal to a first coil of the plurality of coils;
- and
- outputting the first delayed signal to a second coil of the plurality of coils.
A system for driving a loudspeaker having a plurality of coils, the system comprising:
- a modulator for receiving an input signal and outputting a first pulse width modulated (PWM) output signal for driving a first coil of the plurality of coils;
- a finite impulse filter (FIR) arrangement for receiving the first PWM output signal and to outputting a second PWM output signal for driving a second coil of the plurality of coils,
- wherein the FIR arrangement is configured to adapt to a variation in a frequency of the first PWM output signal output so as to suppress a carrier of the first PWM output signal.
A system for driving a loudspeaker having a plurality of coils, the system comprising:
- a modulator configured to receive an input signal and to output a pulse width modulated (PWM) output signal representative of the received input signal;
- a delay element for receiving and applying a delay to the PWM output signal to generate a first delayed signal;
- a first output configured to be coupled to a first coil of the plurality of coils of the loudspeaker, wherein the first output is coupled to the output of the modulator;
- and
- a second output configured to be coupled to a second coil of the plurality of coils of the loudspeaker, wherein the second output is coupled to the output of the delay element;
- wherein the delay element is configured to apply a delay equal to one period of the output PWM signal to the output PWM signal.
A system for driving a loudspeaker having a plurality of coils, the system comprising:
- a modulator configured to receive an input signal and to output a pulse width modulated (PWM) output signal representative of the received input signal;
- a delay element for receiving and applying a delay to the PWM output signal to generate a first delayed signal;
- a first output configured to be coupled to a first coil of the plurality of coils of the loudspeaker, wherein the first output is coupled to the output of the modulator;
- and
- a second output configured to be coupled to a second coil of the plurality of coils of the loudspeaker, wherein the second output is coupled to the output of the delay element;
- wherein the delay element forms at least part of a finite impulse response (FIR) filter arrangement.
A system for driving a loudspeaker having a plurality of coils, the system comprising:
- a modulator configured to receive an input signal and to output a pulse width modulated (PWM) output signal representative of the received input signal;
- a delay element for receiving and applying a delay to the PWM output signal to generate a first delayed signal;
- a first output configured to be coupled to a first coil of the plurality of coils of the loudspeaker, wherein the first output is coupled to the output of the modulator;
- and
- a second output configured to be coupled to a second coil of the plurality of coils of the loudspeaker, wherein the second output is coupled to the output of the delay element;
- wherein a carrier frequency of the PWM output signal can be modulated based on a control signal issued by a controller of a host device that incorporates the system.
Dependencies are inferred from the claim text.