Semiconductor Device And Electronic Apparatus

A semiconductor device 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 configured to modulate a signal based on a sound source signal to output a first modulated signal and a second modulated signal;
• a first amplifier circuit configured to output a first amplified signal obtained by amplifying the first modulated signal to the first output terminal in a first operation mode;
• a second amplifier circuit configured to output a second amplified signal obtained by amplifying the second modulated signal to the second output terminal in the first operation mode;
• a test signal generation circuit configured to modulate a test signal in which a frequency is changed in a preset frequency band to generate a third modulated signal and a fourth modulated signal in a second operation mode;
• and
• a peak frequency detection circuit configured to measure a potential difference between the first output terminal and the second output terminal, and detect a frequency range including a peak frequency that is the frequency of the test signal at which an impedance of the sound reproduction device peaks in the second operation mode, wherein
• the first amplifier circuit outputs a third amplified signal obtained by amplifying the third modulated signal to the second output terminal in the second operation mode,
• the second amplifier circuit outputs a fourth amplified signal obtained by amplifying the fourth modulated signal to the second output terminal in the second operation mode,
• the first amplifier circuit includes a plurality of inverter circuits each having an output terminal coupled to the first output terminal,
• the second amplifier circuit includes a plurality of inverter circuits each having an output terminal coupled to the second output terminal,
• in the first operation mode, the first modulated signal is input to input terminals of the plurality of inverter circuits provided in the first amplifier circuit, and the second modulated signal is input to input terminals of the plurality of inverter circuits provided in the second amplifier circuit, and
• in the second operation mode, the third modulated signal is input to input terminals of some of the plurality of inverter circuits provided in the first amplifier circuit, output terminals of other inverter circuits among the plurality of inverter circuits provided in the first amplifier circuit have high impedances, the fourth modulated signal is input to input terminals of some of the plurality of inverter circuits provided in the second amplifier circuit, and output terminals of other inverter circuits among the plurality of inverter circuits provided in the second amplifier circuit have high impedances.