| 摘要 |
PURPOSE: A class-D amplifier circuit is provided to control the relation between non-attenuation levels and attenuation levels of input signals according to resistance values of first resistance and second resistance. CONSTITUTION: A class-D amplifier circuit(100) includes an amplifier(20), a first attenuator(30), a second attenuator(40), and a control circuit(45). The amplifier generates two pulse width modulation output signals having a regular phase and a reversed phase. The first attenuator is located between extended input paths(16a,16b) from an input terminal to an input terminal of the amplifier. The second attenuator includes a switch(42) located in parallel with a transistor of the first attenuator. The control circuit controls the switch between an ON state and an OFF state. The control circuit intermittently controls the switch in a short enough interval in comparison to a triangle wave signal.
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