Pravel, Hewitt, Kimball & Krieger
Apparatus for eliminating audio noise when power is cycled to a computer
 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. 
Compaq Computer Corporation
H H H
H03G H04R H03F
inventional additional inventional
Thanh Thien
Tran