Audio circuit
AssigneeRohm Co., Ltd.
InventorMitsuteru Sakai
Life of this patent
Estimating the term…
Abstract
An audio circuit is configured to allow an analog voltage to be input via its volume setting pin. A power supply pin receives a power supply voltage. A bias circuit generates a first reference voltage that corresponds to the analog voltage. A D/A converter converts a digital audio signal into an analog audio signal. AD/A converter has a variable voltage range with a full scale that can be changed according to the first reference voltage. A class D amplifier outputs an output pulse signal having a duty cycle that corresponds to the analog audio signal output from the D/A converter and having an amplitude that corresponds to the power supply voltage.
Claims8
An audio circuit comprising:
- a volume setting pin structured to receive an analog voltage;
- a power supply pin structured to receive a power supply voltage;
- a bias circuit structured to generate a first reference voltage that corresponds to the analog voltage;
- a D/A converter structured to convert a digital audio signal into an analog audio signal with a voltage range having a full scale that is variable according to the first reference voltage;
- and
- a class D amplifier structured to output an output pulse signal having a duty cycle that corresponds to the analog audio signal output from the D/A converter and having an amplitude that corresponds to the power supply voltage.
Dependencies are inferred from the claim text.