SIGNAL OUTPUT CIRCUIT, AUDIO SIGNAL OUTPUT APPARATUS USING THE SAME, AND ELECTRONIC DEVICE

摘要

A signal output circuit wherein noise is prevented from occurring upon a power-up and a power-down. A selecting circuit (30) selectively outputs a non-significant PWM signal NSPWM or a significant PWM signal SPWM in accordance with a power supply transition period or a normal period. A non-significant signal generating circuit (20) generates a gradually rising signal, which is then amplified by a second driver circuit (32), whereby a DC block capacitor C2 is gradually charged and discharged, thereby preventing noise from occurring due to an inrush current.