Semiconductor device and electronic apparatus

A semiconductor device coupled to a sound source reproduction circuit including an input terminal, a modulation circuit that modulates a signal input to the input terminal to output a first modulated signal and a second modulated signal, and an amplification circuit that outputs a first amplified signal obtained by amplifying the first modulated signal to a first terminal of a sound reproduction device and outputs a second amplified signal obtained by amplifying the second modulated signal to a second terminal of the sound reproduction device, the semiconductor device comprising:

• a first input terminal coupled to the first terminal of the sound reproduction device;
• a second input terminal coupled to the second terminal of the sound reproduction device;
• an output terminal coupled to the input terminal of the sound source reproduction circuit;
• a switch that, in a first operation mode, outputs a signal based on a sound source signal to the output terminal and that, in a second operation mode, outputs a test signal of which a frequency is changed in a predetermined frequency band to the output terminal;
• a test signal generation circuit that, in the second operation mode, outputs the test signal to the switch;
• a peak frequency detection circuit that, in the second operation mode, measures a potential difference between the first input terminal and the second input terminal to detect a peak frequency that is a frequency of the test signal at which an impedance of the sound reproduction device reaches a peak;
• and
• a determination circuit that, in the second operation mode, determines whether or not the peak frequency is included in a reference frequency range determined based on the predetermined frequency band and temperature information that is information on a temperature of the sound reproduction device.

An electronic apparatus comprising:

• a first output terminal coupled to a first terminal of a sound reproduction device;
• a second output terminal coupled to a second terminal of the sound reproduction device;
• a modulation circuit that, in a first operation mode, modulates a signal based on a sound source signal to output a first modulated signal and a second modulated signal and that, in a second operation mode, modulates a test signal of which a frequency is changed in a predetermined frequency band, to output a third modulated signal and a fourth modulated signal;
• a test signal generation circuit that, in the second operation mode, outputs the test signal to the modulation circuit;
• an amplification circuit that, in the first operation mode, outputs a first amplified signal obtained by amplifying the first modulated signal to the first output terminal and outputs a second amplified signal obtained by amplifying the second modulated signal to the second output terminal and that, in the second operation mode, outputs a third amplified signal obtained by amplifying the third modulated signal to the first output terminal and outputs a fourth amplified signal obtained by amplifying the fourth modulated signal to the second output terminal;
• a peak frequency detection circuit that, in the second operation mode, measures a potential difference between the first output terminal and the second output terminal to detect a peak frequency that is a frequency of the test signal at which an impedance of the sound reproduction device reaches a peak;
• and
• a determination circuit that, in the second operation mode, determines whether or not the peak frequency is included in a reference frequency range determined based on the predetermined frequency band and temperature information that is information on a temperature of the sound reproduction device.