Patent ID: 8014531

Claim:
A stereo/monaural switching circuit comprising: first and second loudspeaker amplifiers that drive loudspeakers, respectively; a determination unit that determines whether or not power is being supplied to at least the second loudspeaker amplifier; a mixing unit that mixes a first-channel sound signal and a second-channel sound signal with each other and outputs a mixed signal; a switching unit that performs a switching operation with respect to a transmission path of a sound signal so that, when the determination unit determines that power is being supplied to the second loudspeaker amplifier, the first-channel sound signal and the second-channel sound signal are respectively supplied to the first loudspeaker amplifier and the second loudspeaker amplifier, and when the determination unit determines that power is not being supplied to the second loudspeaker amplifier, an output signal of the mixing unit is supplied to the first loudspeaker amplifier for monaural reproduction; and a power down control unit that, if the determination unit determines that power is not being supplied to the second loudspeaker amplifier, forces the second loudspeaker amplifier and a circuit for driving the second loudspeaker amplifier to be in a power-down state.