Audio control circuit for a computer system system having an energy-saving feature
AssigneeChuntex Electronic Co., Ltd.
InventorChang-lung Kang
Life of this patent
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Abstract
To allow sounds to be output by the audio amplifier of a multi-media computer system during periods of CPU inactivity and display screen blanking, a switch is added to the control circuit of the audio amplifier which overrides the energy-saving shut-down program which would normally be activated to cut-off power to both the monitor display screen and the audio amplifier. The switch is in the form of a transistor whose control electrode is connected to both the power supply and to the CPU, such that the transistor can be turned on either by a signal from the main power circuit or by a keyboard activated signal from the CPU's microprocessor, the collector of the transistor being connected to the audio input terminal of the audio amplifier.
Claims2
An audio control circuit for a computer system having a CPU including a microprocessor, a monitor, and an audio amplifier, and means for switching to an energy-saving state by shutting down the monitor when the CPU is inactive for a predetermined period of time,
- wherein said computer system further includes means for maintaining a supply of power to said audio amplifier when said computer system is in said energy-saving state,
- wherein said means for maintaining a supply of power to said audio amplifier is a switch circuit controlled by an audio signal output terminal of the microprocessor and connected between a power circuit an audio input of the audio amplifier, and
- wherein said switch circuit comprises:
- a transistor having a control electrode connected to the audio signal output terminal of the microprocessor such that when the control electrode of the transistor is in a first state, an input terminal of the audio amplifier is cut-off, and when the control electrode of the microprocessor is in a second state, the input terminal of the microprocessor is allowed to receive audio signals, and
- means connected between the control electrode of the transistor and a power circuit for switching the monitor to an energy-saving state by switching said transistor from said second state to said first state, wherein said output terminal of the microprocessor is arranged to override the energy-saving means and switch said transistor from the first state to the second state in response to activation of a switch controlling said output terminal.
Dependencies are inferred from the claim text.