Volume adjustment device, digital amplifier, and digital signal reproducing device
First Claim
1. A digital amplifier, in which a driving circuit drives switching elements in response to an audio signal that has been converted into a 1-bit signal, and an amplitude of the audio signal is amplified by switching a power source voltage, comprising:
- variable power source voltage generating means for generating the power source voltage which is variable; and
driving voltage variation means for causing a driving voltage, by which the driving circuit drives the switching elements, to follow the power source voltage so as to vary the driving voltage.
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Abstract
A digital amplifier causes a gate drive circuit to drive output transistors, and switches a power source voltage supplied from a variable voltage power source, thereby amplifying an amplitude of a 1-bit digital signal outputted from a ΔΣ block. A variable voltage power source varies a driving voltage, by which an upper gate drive circuit drives output transistors, as a voltage obtained by adding (i) a constant voltage supplied to a lower gate drive circuit to (ii) a power source voltage, so as to correspond to the power source voltage. Thus, the driving voltage is minimized without influencing a switching operation of the output transistors. As a result, it is possible to reduce power consumption of the upper gate drive circuit in turning down the volume.
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Citations
5 Claims
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1. A digital amplifier, in which a driving circuit drives switching elements in response to an audio signal that has been converted into a 1-bit signal, and an amplitude of the audio signal is amplified by switching a power source voltage, comprising:
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variable power source voltage generating means for generating the power source voltage which is variable; and driving voltage variation means for causing a driving voltage, by which the driving circuit drives the switching elements, to follow the power source voltage so as to vary the driving voltage. - View Dependent Claims (2)
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3. A digital signal reproduction device, comprising:
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a reproduction circuit for demodulating and developing sound data, obtained from a rewritable optical storage medium, which has been modulated and compressed for storage; and an amplifier for amplifying the sound data, wherein the amplifier is a digital amplifier that includes a driving circuit driving switching elements in response to an audio signal that has been converted into a 1-bit signal, and an amplitude of the audio signal is amplified by switching a power voltage, a variable power source voltage generator generating the power source voltage which is variable, and a driving voltage variator that causes a driving voltage, by which the driving circuit drives the switching elements, to follow the power source voltage so as to vary the driving voltage. - View Dependent Claims (4, 5)
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Specification