Patent ID: 11936349
Assignee: ROHM CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 13:
14. A vehicle audio system, comprising:
a speaker;
a filter, including an output node connected to the speaker; and
an audio circuit, comprising:
an output terminal, connected to the filter;
a bridge circuit, including an output node connected to the output terminal;
an integrator, integrating and outputting a difference between an input signal and a feedback signal corresponding to an output signal generated at the output terminal in a non-mute period in which a mute control signal is negated, and outputting a predetermined bias voltage in a mute period in which the mute control signal is asserted, wherein the input signal is fixed at a predetermined voltage level in the mute period;
a periodic voltage generating circuit, generating a periodic voltage of a triangular wave or sawtooth wave;
a comparator, comparing an output of the integrator with the periodic voltage; and
a driver, switching the bridge circuit according to an output of the comparator in the non-mute period, and fixing an output of the bridge circuit in the mute period;
a pre-amplifier disposed on a front end of the class D amplifier circuit, wherein the pre-amplifier fixes its output to the predetermined voltage level in the mute period.