Anti-pop circuit
First Claim
Patent Images
1. A reduced pop amplifier comprising:
- an amplifier stage;
an output stage comprising;
a core having an input coupled to the amplifier stage; and
a compensation network coupled between the input of the core and an output of the core, the compensation network comprising a capacitor, the compensation network disconnects the input of the core from the output of the core and shunts the capacitor to a low voltage when the amplifier stage is powered down and until after the amplifier stage is powered up, and the compensation network connects the input of the core to the output of the core after the amplifier stage is powered up and until before the amplifier stage is powered down.
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Abstract
Presently many audio chips suffer from pop issues, which is especially serious for single ended audio drivers. An audio pop is a disturbance in the output caused by a sudden transition of chip power, particularly when a chip is powered on or powered off. Furthermore, compensation networks included in the amplifiers on audio chips for stability offer a significant path for transmitting power disturbances to the output. Hence, circuitry is developed to suppress pops in the output stages of an amplifier.
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Citations
20 Claims
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1. A reduced pop amplifier comprising:
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an amplifier stage; an output stage comprising; a core having an input coupled to the amplifier stage; and a compensation network coupled between the input of the core and an output of the core, the compensation network comprising a capacitor, the compensation network disconnects the input of the core from the output of the core and shunts the capacitor to a low voltage when the amplifier stage is powered down and until after the amplifier stage is powered up, and the compensation network connects the input of the core to the output of the core after the amplifier stage is powered up and until before the amplifier stage is powered down. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for reducing pop in an amplifier circuit comprising:
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receiving a control signal; when the control signal is low, performing the steps of; breaking a connection between an input and an output of an output stage in an amplifier circuit to prevent current from flowing between the output and the input; shunting a capacitor coupled to the amplifier circuit to a low voltage after breaking the connection; and connecting the output to the low voltage; and wherein the control signal is low when the amplifier is powered down, remains low until after the amplifier is powered up and remains high until before the amplifier is subsequently powered down. - View Dependent Claims (12, 13, 14, 20)
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15. A reduced pop amplifier comprising:
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an amplifier stage; an output stage comprising; a core stage having an input coupled to the amplifier stage and an output; a compensation network comprising a capacitor coupled to the input and the output; a switch for pulling the output to a low voltage; a second input to the core; a second output to the core; and a second compensation network comprising a capacitor coupled to the second input and the second output. - View Dependent Claims (16, 17, 18, 19)
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Specification