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Patent US5734729A successfully refreshed from Google Patents.
US5734729A
Expired / Lapsed
US
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Apparatus for eliminating audio noise when power is cycled to a computer
Assignee: Hewlett Packard Development Co LP
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Filing: 1996-01-17
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Granted: 1998-03-31
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Expires: 2016-01-17
Abstract
Abstract An audio power management system for a computer to eliminate audible noise associated with the cycling of power to an audio amplifier for a computer is disclosed. A diode is connected between the power supply rail and the power input to the audio amplifier. One or more decoupling capacitors is provided at the power input to the audio amplifier to insulate the audio amplifier from fluctuations at the voltage supply rail. The apparatus also briefly mutes the amplifier when power is cycled to eliminate transient noises. Additionally, the audio power management system eliminates audible noise associated with the waking-up or putting the computer to sleep. The audio system asserts a speaker mute signal before power is removed from the amplifier to reduce transient conditions. During power up, the speaker mute signal is applied to the amplifier for a period after power has been applied to the amplifier. This control is economically accomplished using a minimal number of digital outputs.
Inventors
- 👤 Thanh Thien Tran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:11
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/68; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/34; H03G3/348; H04; H04R; H04R3/00; H04R3/007
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
157 words
An apparatus for controlling speaker noise resulting from transients generated by the cycling of power to a computer system, said computer system having a voltage supply rail, a status signal indicative of the stability of power on said voltage supply rail, and having an audio signal, said apparatus comprising: an amplifier for amplifying said audio signal, said amplifier having a volume control input and a power supply input; a power switch coupled between said voltage supply rail and said power supply input of said amplifier, said power switch enabling power to be transferred only from said voltage supply rail to said power supply input of said amplifier; an energy reservoir coupled to said power supply input of said amplifier; and a mute switch having a control input coupled to said status signal and an output coupled to said volume control input of said amplifier, said mute switch muting said amplifier upon the assertion of said status signal.
Claim 2
Independent Claim
157 words
An apparatus for controlling speaker noise resulting from transients generated by the cycling of power to a computer system, said computer system having a voltage supply rail, a status signal indicative of the stability of power on said voltage supply rail, and having an audio signal, said apparatus comprising: an amplifier for amplifying said audio signal, said amplifier having a volume control input and a power supply input; a power switch coupled between said voltage supply rail and said power supply input of said amplifier, said power switch enabling power to be transferred only from said voltage supply rail to said power supply input of said amplifier; an energy reservoir coupled to said power supply input of said amplifier; and a mute switch having a control input coupled to said status signal and an output coupled to said volume control input of said amplifier, said mute switch muting said amplifier upon the assertion of said status signal.
Claim 3
Dependent Claim
14 words
The apparatus of claim 1, wherein said energy reservoir is one or more capacitors.
Claim 4
Dependent Claim
33 words
The apparatus of claim 1, wherein said amplifier has an audio input for receiving said audio signal, said apparatus further comprising a low-pass filter coupled between said audio signal and said audio input.
Claim 5
Dependent Claim
84 words
The apparatus of claim 3, wherein said low-pass filter further comprises: a first resistor having a first end and a second end, said first end coupled to said audio input; a second resistor and a first capacitor having first ends coupled to the second end of said first resistor and having second ends coupled to ground; a second capacitor having a first end coupled to said second end of said first resistor and a second end coupled to said audio input of said amplifier.
Claim 6
Dependent Claim
24 words
The apparatus of claim 1, further comprising an electromagnetic interference filter coupled between said status signal and said control input of said mute switch.
Claim 7
Dependent Claim
58 words
The apparatus of claim 5, wherein said electromagnetic interference filter comprises: a resistor having a first end coupled to said status signal and a second end coupled to said control input of said mute switch; and a capacitor having a first end connected to said control input of said mute switch and a second end coupled to ground.
Claim 8
Dependent Claim
38 words
The apparatus of claim 1, wherein said power switch is a diode having cathode and anode ends, said anode end coupled to said voltage supply rail, said cathode end coupled to said power supply input of said amplifier.
Claim 9
Dependent Claim
139 words
The apparatus of claim 1, wherein said computer system has a second audio signal, said apparatus further comprising: a second amplifier for amplifying said second audio signal, said second amplifier having a volume control input and a power supply input; a second power switch coupled between said voltage supply rail and said power supply input of said second amplifier, said second power switch enabling power to be transferred only from said voltage supply rail to said power supply input of said second amplifier; a second energy reservoir coupled to said power supply input of said second amplifier; and a second mute switch having a control input coupled to said status signal and an output coupled to said volume control input of said second amplifier, said second mute switch muting said second amplifier upon the assertion of said status signal.
Claim 10
Dependent Claim
137 words
A computer system comprising: a voltage supply rail; a status signal indicative of the stability of power on said voltage supply rail; a CODEC for generating an audio signal; an amplifier for amplifying said audio signal, said amplifier having a volume control input and a power supply input; a power switch coupled between said voltage supply rail and said power supply input of said amplifier, said power switch enabling power to be transferred only from said voltage supply rail to said power supply input of said amplifier; an energy reservoir coupled to said power supply input of said amplifier; and a mute switch having a control input coupled to said status signal and an output coupled to said volume control input of said amplifier, said mute switch muting said amplifier upon the assertion of said status signal.
Claim 11
Dependent Claim
137 words
A computer system comprising: a voltage supply rail; a status signal indicative of the stability of power on said voltage supply rail; a CODEC for generating an audio signal; an amplifier for amplifying said audio signal, said amplifier having a volume control input and a power supply input; a power switch coupled between said voltage supply rail and said power supply input of said amplifier, said power switch enabling power to be transferred only from said voltage supply rail to said power supply input of said amplifier; an energy reservoir coupled to said power supply input of said amplifier; and a mute switch having a control input coupled to said status signal and an output coupled to said volume control input of said amplifier, said mute switch muting said amplifier upon the assertion of said status signal.
Claim 12
Dependent Claim
15 words
The computer system of claim 9, wherein said energy reservoir is one or more capacitors.
Claim 13
Dependent Claim
34 words
The computer system of claim 9, wherein said amplifier has an audio input for receiving said audio signal, said apparatus further comprising a low-pass filter coupled between said audio signal and said audio input.
Claim 14
Dependent Claim
85 words
The computer system of claim 11, wherein said low-pass filter further comprises: a first resistor having a first end and a second end, said first end coupled to said audio input; a second resistor and a first capacitor having first ends coupled to the second end of said first resistor and having second ends coupled to ground; a second capacitor having a first end coupled to said second end of said first resistor and a second end coupled to said audio input of said amplifier.
Claim 15
Dependent Claim
25 words
The computer system of claim 9, further comprising an electromagnetic interference filter coupled between said status signal and said control input of said mute switch.
Claim 16
Dependent Claim
59 words
The computer system of claim 13, wherein said electromagnetic interference filter comprises: a resistor having a first end coupled to said status signal and a second end coupled to said control input of said mute switch; and a capacitor having a first end connected to said control input of said mute switch and a second end coupled to ground.
Claim 17
Dependent Claim
39 words
The computer system of claim 9, wherein said power switch is a diode having cathode and anode ends, said anode end coupled to said voltage supply rail, said cathode end coupled to said power supply input of said amplifier.
Claim 18
Dependent Claim
140 words
The computer system of claim 9, wherein said CODEC further generates a second audio signal, said apparatus further comprising: a second amplifier for amplifying said second audio signal, said second amplifier having a volume control input and a power supply input; a second power switch coupled between said voltage supply rail and said power supply input of said second amplifier, said second power switch enabling power to be transferred only from said voltage supply rail to said power supply input of said second amplifier; a second energy reservoir coupled to said power supply input of said second amplifier; and a second mute switch having a control input coupled to said status signal and an output coupled to said volume control input of said second amplifier, said second mute switch muting said second amplifier upon the assertion of said status signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-03-30 | 2001-09-29 | 2002-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-30 | 2005-09-29 | 2006-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-30 | 2009-09-29 | 2010-03-31 | $7700.00 | Window Closed / Lapsed |