Onkyo Corporation

Yoshitaka Handa

Mamoru Sekiya

Sadatoshi Hisamoto

Shuichi Hiza

Joji Kasai

Norio Umezu

Kazuhiro Hida

Kazutaka Murayama

Sou Fujioka

A switching amplifier including a PWM circuit, a driver, a switching output circuitand an LPFis provided with a fluctuation detection circuitfor detecting fluctuations in the power supply voltage. The fluctuation detection circuitincludes detection resistorsandconnected in series between a positive power supplyand a negative power supply. A fluctuating signal RPL occurring at a fluctuation detection terminalis supplied to the inverted input terminal of a differential amplifierof a non-inverted amplifier circuit. The non-inverted amplifier circuitinverts the fluctuating signal RPL, mixes the inverted fluctuating signal into the input signal e, amplifies the mixed signal, and supplying the amplified signal to the PWM circuit

Switching amplifier

A pulse width modulation circuit of the present invention includes: pulse generation means being provided with a first power supply and charged with a first current and a second current between which a constant current is distributed to turn ON/OFF a switching element, thereby generating a pulse from a first output section; pulse modulation means for controlling the charging while controlling a distribution ratio between the first current and the second current based on an input signal, thereby changing a pulse width of the output pulse; and first short circuit means for shorting the first output section with the first power supply when the pulse being output from the first output section transitions to a voltage of the first power supply.

Pulse width modulation circuit

Growing community of inventors

Sakai, Japan

Yoshitaka Handa