Method and apparatus for circuit with low IC power dissipation and high dynamic range

Patent metadata

Field	Value
Publication number	US-9065413-B2
Application number	US-201213443525-A
Country	US
Kind code	B2
Filing date	Apr 10, 2012
Priority date	Jan 25, 2012
Publication date	Jun 23, 2015
Grant date	Jun 23, 2015

Abstract

An apparatus comprises a selected volume detector that detects a selected output volume; an analog output signal amplifier; a digital volume amplifier; a boost gain control element coupled to the selected volume detector; the analog output signal amplifier; and the digital volume amplifier; wherein the boost gain control element is configured to: keep a gain of a path of the digital volume amplifier and the analog output signal amplifier substantially constant, wherein the boost gain control element can adjust both: a) a gain of the digital volume control; and b) a gain of the analog output signal amplifier; to keep the gain of the path of the digital volume amplifier and the analog output signal substantially constant and equal to the selected output volume.

First claim

What is claimed is:

1. An apparatus, comprising:
a selected volume detector that detects a selected output audio signal volume;
an analog output signal amplifier;
a digital volume amplifier; and
a boost gain control element coupled to
the selected volume detector;
the analog output signal amplifier; and
the digital volume amplifier;

wherein the boost gain control element is configured to:
keep a gain of a path of the digital volume amplifier and the analog output signal amplifier substantially constant, wherein the boost gain control element can adjust both:
a) a gain of the digital volume amplifier; and
b) a gain of the analog output signal amplifier;
to keep the gain of the path of the digital volume amplifier and the analog output signal amplifier substantially constant and equal to the selected output volume, wherein the boost gain control element is further configured to:

compare the selected output volume to a threshold value;
if the selected output volume is below the threshold, then the boost gain control element can:
a) adjust upwards a digital volume of the digital volume amplifier; and
b) adjust downwards a volume of the of an analog output signal amplifier

to keep the gain of the path of the digital volume amplifier and the analog output signal amplifier substantially constant and equal to the selected output volume.

2. The apparatus of claim 1 , wherein the boost gain control element is further configured to:
compare the selected volume to a threshold value;
if the given volume of amplitude is above the threshold, then the boost gain control element can:
a) adjust downwards a digital volume of the digital volume amplifier; and
b) adjust upwards a volume of the analog output signal amplifier,

to keep the gain of the path of the digital volume amplifier and the analog output signal amplifier substantially constant and seeks to be equal to the selected output volume.

3. The apparatus of claim 1 , further comprising a digital signal processor, wherein an output of the digital signal processor is coupled to an input of the digital volume amplifier.

4. The apparatus of claim 1 , wherein the analog output signal amplifier is a “Class G” charge pump.

5. The apparatus of claim 1 , wherein the selected volume detector is coupled to a digital signal processor that receives a selected volume signal.

6. The apparatus of claim 1 , wherein
a threshold of a boost mode is substantially 18 decibels (“dB”) of amplification;
a dynamic range of the digital volume amplifier is an increase of substantially 12 dB; and
a dynamic range of the analog output signal amplifier as adjusted by the boost gain control element is substantially −12 dB.

7. The apparatus of claim 6 , wherein there is a transition period between a unity amplification of the digital volume amplifier and a 12 db value, wherein the digital volume amplifier transitions at a substantial 1 dB change.

8. An apparatus, comprising:
a selected volume detector that detects a selected output audio signal volume;
an analog output signal amplifier;
a digital volume amplifier; and
a boost gain control element coupled to
a) the selected volume detector;
b) the analog output signal amplifier; and
c) the digital volume amplifier;

wherein the boost gain control element is configured to:
keep a gain of a path of the digital volume amplifier and the analog output signal amplifier substantially constant,

wherein the boost gain control element can adjust both:
a) a gain of the digital volume amplifier; and
b) a gain of the analog output signal amplifier;

to keep the gain of the path of the digital volume amplifier and the analog output signal amplifier substantially constant and equal to the selected output volume,
wherein the boost gain control element is further configured to:
compare the selected output volume to a threshold value;
if the selected output volume is below the threshold, then the boost gain control element can:
a) adjust upwards a digital volume of the digital volume amplifier; and
b) adjust downwards a volume of the analog output signal amplifier,

to keep the gain of the path of the digital volume amplifier and the analog output signal amplifier substantially constant and equal to the selected output volume.

9. The apparatus of claim 8 , wherein the boost gain control element is further configured to:
compare the selected volume to a threshold value;
if the given volume of amplitude is above the threshold, then the boost gain control element can:
a) adjust downwards a digital volume of the digital volume amplifier; and
b) adjust upwards a volume of the analog output signal amplifier,

to keep the gain of the path of the digital volume amplifier and the analog output signal amplifier substantially constant and equal to the selected output volume.

10. The apparatus of claim 8 , further comprising a digital signal processor, wherein an output of the digital signal processor is coupled to an input of the digital volume amplifier.

11. The apparatus of claim 8 , wherein the analog output signal amplifier is a “Class G” charge pump.

12. The apparatus of claim 8 , wherein the selected volume detector is coupled to a digital signal processor that receives a selected volume signal.

13. A method, comprising:
determining if a selected audio output volume is greater than a volume threshold;
increasing a gain of a digital amplifier if the selected output volume is not greater than the threshold volume;
decreasing a gain of an analog output signal amplifier if the selected output volume is not greater than the threshold volume; and
wherein the gain of a path of the digital amplifier and the analog output signal amplifier is substantially constant and seeks to be equal to the selected output volume.

14. The method of claim 13 , further comprising:
playing an audio stream at the selected output volume.

15. The method of claim 13 , further comprising:
determining if a gain of the digital amplifier is greater than an allowable gain of the digital amplifier if the selected output volume is not greater than the volume threshold.

16. The method of claim 13 , further comprising
determining if the selected output volume is less than the volume threshold for a first time lapse; and
determining if an update of of at least one of the digital amplifier and the analog output signal amplifier occurred within a second time lapse ago.

17. The method of claim 13 , wherein the selected output volume is generated with aid of an “Class G” charge pump.

18. The method of claim 17 , further comprising:
playing an audio stream at the selected output volume.

Assignees

• Pereira Angelo William
• Fontaine Paul-Herve Aymeric
• Vercier Michel
• Trehan Chintan
• Saw Sooping
• Chellappa Balaji Narendran
• Texas Instruments Inc

Inventors

• Pereira Angelo William
• Fontaine Paul-Herve Aymeric
• Vercier Michel
• Trehan Chintan
• Saw Sooping
• Chellappa Balaji Narendran

Classifications

• H03G3/3005 Primary

  in amplifiers suitable for low-frequencies, e.g. audio amplifiers (H03G3/32, H03G3/34 take precedence) · CPC title

• H03G3/3089

  Control of digital or coded signals · CPC title