Digitally controlled power supplies for an audio amplifier
View Patent ↗An audio playback loop circuit including an audio amplifier for amplifying an analog audio signal based on digitally controlled power supplies, and a digitally controlled power supply selection circuit for generating and selecting the digitally controlled power supplies based on a digital signal.
1. An audio playback loop circuit comprising:
an audio amplifier for amplifying an analog audio signal based on digitally controlled power supplies;
a digital-to-analog converter for generating said analog audio signal, wherein said audio amplifier receives said analog audio signal directly from said digital-to-analog converter; and
a digitally controlled power supply selection circuit for generating and selecting said digitally controlled power supplies based on a digital signal, wherein said audio amplifier receives said digitally controlled power supplies only from said digitally controlled power supply selection circuit, wherein said digitally controlled power supply selection circuit comprises:
a digital signal amplitude monitor for generating a monitoring voltage based on an amplitude of said digital signal; and
a programmable charge pump for generating said digitally controlled power supplies based on said monitoring voltage and an analog voltage.
2. The audio playback loop circuit of claim 1 , wherein said audio amplifier comprises:
a class-G audio amplifier.
3. The audio playback loop circuit of claim 1 , wherein said digitally controlled power supply selection circuit comprises:
a two-level digitally controlled power supply selection circuit.
4. The audio playback loop circuit of claim 1 , wherein said digitally controlled power supply selection circuit comprises:
a multi-level digitally controlled power supply selection circuit, wherein said multi-level is more than two levels.
5. The audio playback loop circuit of claim 1 , wherein said digitally controlled power supply selection circuit further comprises:
a multi-level digital signal amplitude monitor.
6. The audio playback loop circuit of claim 1 , wherein said programmable charge pump further comprises:
a multi-level programmable positive/negative charge pump.
7. The audio playback loop circuit of claim 1 , further comprising:
a finite impulse response filter for allowing an output of an amplitude of said digital signal.
8. The audio playback loop circuit of claim 1 , further comprising:
a digital delta-sigma modulator for receiving an input from a finite impulse response filter.
9. A device comprising:
a digital audio signal receiver for receiving a digital audio signal;
an audio amplifier for amplifying an analog audio signal based on digitally controlled power supplies;
a digital-to-analog converter for generating said analog audio signal, wherein said audio amplifier receives said analog audio signal directly from said digital-to-analog converter;
a digitally controlled power supply selection circuit for generating and selecting said digitally controlled power supplies based on a digital signal, wherein said audio amplifier receives said digitally controlled power supplies only from said digitally controlled power supply selection circuit, wherein said digitally controlled power supply selection circuit comprises:
a digital signal amplitude monitor for generating a monitoring voltage based on an amplitude of said digital signal; and
a programmable charge pump for generating said digitally controlled power supplies based on said monitoring voltage and an analog voltage; and
an audio output interface.
10. The device of claim 9 , wherein said audio amplifier comprises:
a class-G audio amplifier.
11. The device of claim 9 , wherein said digitally controlled power supply selection circuit comprises:
a multi-level digitally controlled power supply selection circuit.
12. The device of claim 9 , wherein said digitally controlled power supply selection circuit further comprises:
a multi-level digital signal amplitude monitor.
13. The device of claim 9 , wherein said audio output interface comprises:
a headphone jack.
14. The device of claim 9 , wherein said audio output interface comprises:
a speaker.
15. A method for digitally controlling power supply selections for an audio amplifier, said method comprising:
receiving an analog audio signal, by an audio amplifier, directly from a digital-to-analog converter;
amplifying said analog audio signal, by said audio amplifier, based on digitally controlled power supplies;
generating said digitally controlled power supplies based on a digital signal by a digitally controlled power supply selection circuit, wherein said generating said digitally controlled power supplies is further based on an analog voltage and a monitoring voltage;
selecting said digitally controlled power supplies based on said digital signal by said digitally controlled power supply selection circuit; and
directly receiving said digitally controlled power supplies by said audio amplifier only from said digitally controlled power supply selection circuit.
16. The method of claim 15 , further comprising:
generating a monitoring voltage based on an amplitude of said digital signal.