Alpine Electronics, Inc.

Alps Alpine Co., Ltd.

Minoru Matsuyama

Yoshikazu Maeda

Masashi Saito

Taro Kitagawa

A sound output device of the present disclosure includes a controller, a power amplifier, a low-pass filter, and a speaker. The controller includes first and second low-pass filters configured to remove high-frequency components of a sound input signal and a sound output signal, a first peak detection unit configured to detect a peak current of the sound input signal from which the high-frequency component has been removed, a second peak detection unit configured to detect a peak current of the sound output signal from which the high-frequency component has been removed, and a comparison unit configured to compare the peak current with the peak current and determine connection or disconnection of the speaker when a level of the peak current is equal to or higher than a certain level.

Sound output device

A first fixed filter extracts high-frequency and low-frequency sound signals outside the audible band, and a level integrator integrates levels of the sound signals to obtain a first integrated value. With a second fixed filter, the level integrator integrates levels of sound signals in a low frequency band within the audible band to obtain a second integrated value. A control unit determines whether the high-frequency sound signals are dominant by comparing the first integrated value with the second integrated value. When the high-frequency sound signals are dominant, the control unit attenuates high-frequency speaker drive signals using a variable filter.

Audio control device

An audio apparatus includes a signal processor, a power amplifier, a speaker, and a controller. A current consumption prediction unit in the controller predicts current consumption on the basis of a monitoring result of an output level monitoring unit in the signal processor and/or a monitoring result of a power supply voltage monitoring unit in the controller. A limiter control unit in the controller controls a limiter in the signal processor in a normal mode or a current limiting mode on the basis of predicted current consumption. In the current limiting mode, the limiter is controlled so that an attenuation speed higher than that in the normal mode and a threshold value smaller than that in the normal mode are obtained.

Audio apparatus, and current control method

The present disclosure provides methods and devices for testing a connection between speakers and a power amplifier. The disclosed methods and devices solve a problem that, upon a connection test for a power amplifier which has a booster power source, when a midpoint potential of the power amplifier and the voltage of the speaker connection terminal are compared, and it is determined that short-circuiting occurs on a ground side when the potential of the speaker connection terminal is lower than the midpoint potential, a wrong test is conducted if a midpoint potential is higher than a battery voltage.

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Fukushima, Japan

Minoru Matsuyama