| 摘要 |
PROBLEM TO BE SOLVED: To provide an audio circuit for suppressing a noise.SOLUTION: A D/A converter 210 converts digital audio data Dinto analog differential audio signals V, V. A differential/single end conversion circuit 230 converts the differential audio signals V, Vinto a single end audio signal V. A volume circuit 220 receives the single end audio signal V, and amplifies the signal at a gain corresponding to a volume value. A reference voltage source 240 generates a reference voltage Vto be commonly used for the differential/single end conversion circuit 230 and the volume circuit 220. A calibration circuit 250 shifts at least one of the differential audio signals V, Vby acting on the D/A converter 210 such that a difference between an output voltage Vof the differential/single end conversion circuit 230 and the reference voltage Vapproaches zero during a calibration operation.SELECTED DRAWING: Figure 3 |
