Onkyo Corporation

Mamoru Sekiya

Yoshinori Nakanishi

Tsuyoshi Kawaguchi

Norimasa Kitagawa

Yu Takehara

Youichi Kudoh

Norio Etoh

Joji Kasai

Naofumi Shimasaki

Norio Umezu

Takeru Inoue

Atsushi Minakawa

Yoshitaka Handa

Kazuhiro Hida

Masatoshi Nakabo

Masaaki Inoue

Tsuyoshi Morohashi

Sou Fujioka

Satomi Yamaguchi

Provided is a modulation circuit that can correct an output state in real time and reliably modulate an input signal to output the modulated signal. The signal modulation circuit includes a subtractor, an integrator, a chopper circuit, a frequency divider, and a D-type flip-flop. A delay circuit of a sigma delta modulation circuit is not provided to a feedback circuit, and a signal is delayed and quantized in the D-type flip-flop. The chopper circuit inserts a zero level at timing synchronized with a clock signal, so that pulse density modulation is performed.

Signal modulation circuit

Provided is a circuit which can correct an output state in real time and reduce influences of distortion/noise components generated by a delay device. A signal modulation circuit includes a subtractor, an integrator, a phase inverting circuit, a DFF for while inserting a zero level at timing synchronous with the clock signal, delaying and quantizing the signal, a ternary signal generating circuit for generating a ternary signal for selectively driving a load connected to a single power supply into ternary conductive states including a positive current on-state, a negative current on-state, and an off-state, a driver circuit for generating a driving signal for driving a load, and a feedback circuit for feeding back the driving signal from the driver circuit to the input signal.

Provided is a modulation circuit that can correct an output state in real time and reliably modulate an input signal to output the modulated signal. The signal modulation circuit includes a subtracter, an integrator, a chopper circuit, a frequency divider, and a D-type flip-flop. A delay circuit of a sigma delta modulation circuit is not provided to a feedback circuit, and a signal is delayed and quantized in the D-type flip-flop. The chopper circuit inserts a zero level at timing synchronized with a clock signal, so that pulse density modulation is performed.

A circuit having versatility synthesizes one-bit digital signals to generate a ternary signal. The pulse synthesizing circuit synthesizes one-bit digital signals from two DFFs to generate a ternary signal. The pulse synthesizing circuit has a first NOR gate, a second NOR gate, a third NOR gate, and three switches. The first switch is connected to a first electric potential, the second switch is connected to a second electric potential, and the third switch is connected to a third electric potential. The first to third switches are turned on/off according to logical values of the signals from the two DFFs, and any of the first electric potential, the second electric potential, and the third electric potential is set as an output potential so that a ternary signal is generated.

Pulse synthesizing circuit

A pulse width modulation signal with a less distortion component that is not influenced by a common-mode noise or an offset voltage is generated. Pulse signal generation circuitsgenerate pulse signals S, Swhose pulse widths are discharge times t, tof integrators, respectively, a PWM signal generation circuitdetects discharge end timings of the integratorsbased on the pulse signals S, S, and a pulse whose pulse width is a time between discharge end timing of one of the integratorsand discharge end timing of the other one of the integratorsis generated so as to be output as a PWM signal S.

Pulse width modulator and switching amplifier

A pulse width modulation circuit of the present invention changes a voltage of a charging circuit based on an input signal voltage and in synchronization with a first switching signal; changes, during a predetermined second period following a first period during which the voltage of the charging unit is changed, the voltage of the charging unit in an opposite direction to a direction in which the voltage is changed during the first period, based on a constant bias current; detects time starting from when the second period starts to when the voltage of the charging unit reaches a predetermined reference voltage; and generates, based on the detected time which is repeatedly output each time the first switching signal is output, a pulse signal having a pulse width of the time.

Pulse width modulation circuit and switching amplifier using the same

An amplifying circuit comprises: a first transistor, a second transistor, a third transistor and a fourth transistor provided to an input stage; and a first bias circuit. The input signal is input into a control terminal of the first transistor and a control terminal of the second transistor, a first terminal of the first transistor is connected to a first terminal of the third transistor, a first terminal of the second transistor is connected to a first terminal of the fourth transistor, a second terminal of the first transistor is connected to a first potential, a second terminal of the second transistor is connected to a second potential that is equal to or different from the first potential, a second terminal of the third transistor is connected to a third potential, a second terminal of the fourth transistor is connected to a fourth potential, the first bias circuit is connected between a control terminal of the third transistor and a control terminal of the fourth transistor.

Amplifying circuit and current-voltage conversion circuit

The first emitter follower circuit and the second emitter follower circuit can increase an input impedance on the side of the inverting input terminal in the amplifying circuit. As a result, when a feedback circuit is connected between the inverting input terminal and the output terminal of the amplifying circuit, a fluctuation in a gain of the amplifying circuit according to a configuration of the feedback circuit can be suppressed.

Amplifying circuit

The loudspeaker includes a dome diaphragm that is made of a base material impregnated in a thermosetting resin; a cone diaphragm whose outer circumference side end portion is coupled with an outer circumference end portion of the dome diaphragm; and a voice coil having a bobbin whose one end is coupled to a back surface of the dome diaphragm, and whose outer curved surface is coupled with an inner circumference end portion of the cone diaphragm, wherein the dome diaphragm is provided with a plurality of cone-shaped projections that is formed by hardening the thermosetting resin, projecting from the back surface, and disposed in a circular pattern with a space between each other, the plurality of cone-shaped projections defining a coupling portion to which the one end of the bobbin is coupled.

Loudspeaker

The present invention provides a vibration-damping structure for an audio apparatus, accommodating a main transformer, which becomes a vibration source when driven, the vibration-damping structure including: a main chassis to which a signal processing board for processing an audio signal is attached, the first chassis defining a portion of an outer shape of an assembly of the vibration-damping structure; a sub-chassis fastened to an inner surface of the main chassis so as to be partially in contact with the inner surface of the main chassis via a plurality of fastening members; and a component accommodating chassis fastened to an inner surface of the sub-chassis so as to be partially in contact with the inner surface of the sub-chassis via other fastening members, wherein the main transformer is fixed to the component accommodating chassis.

Vibration-damping structure for audio apparatus

A pulse width modulation circuit includes a first electric-charge accumulator; a second electric-charge accumulator; a first current generator which generates a first current corresponding to the amplitude of an input AC voltage; a second current generator which generates a second current with a constant value; a first current supply controller which supplies the first current to the first electric-charge accumulator; a second current supply controller which supplies the second current to the first electric-charge accumulator; a third current supply controller which supplies the first current to the second electric-charge accumulator; a fourth current supply controller which supplies the second current to the second electric-charge accumulator; and a current limiter which limits the first current to a third current with a predetermined current value, if the amplitude of the AC voltage in the negative side exceeds a predetermined level.

A semiconductor device according to a preferred embodiment of the present invention is a semiconductor device including a main substrate and one or more sub substrates, and the semiconductor device includes first heat generating devices mounted on the sub substrates, sub-substrate heatsinks mounted to the first heat generating devices, and a main-substrate heatsink mounted to the main substrate, wherein the sub-substrate heatsinks and the main-substrate heatsink are secured to each other, such that there is a predetermined positional relationship between the sub substrates and the main substrate.

Semiconductor device including main substrate and sub substrates

A low-pass filter with a high signal-to-noise ratio is provided. A low-pass filter includes a first RC filter circuit, a differential operation circuit subtracting an output signal from a low frequency component of an input signal and outputting a differential signal, a second RC filter circuit, a voltage-current conversion circuit, and a capacitor. The voltage-current conversion circuit includes an operational amplifier, a first resistor, and a feedback circuit generating a feedback voltage in accordance with a voltage applied to the first resistor. If resistance values of first to fourth resistors are R, R, R, R, a relational expression of R*R=R*Ris satisfied, and output current i becomes constant regardless of a resistance value of a load resistance. Since only a first resistor is connected between the input and the output of the voltage-current conversion circuit, thermal noise decreases, and a signal-to-noise ratio becomes high.

Low-pass filter and voltage-current conversion circuit used in the same

A pulse width modulation circuitof the present invention changes the voltage of a first integration circuit Cduring the first period Tof the clock signal MCLK based on a current based on an audio signal eS, changes the voltage of the first integration circuit Cbased on a constant bias current in the opposite direction while changing the voltage of a second integration circuit Cduring the second period T, and changes the voltage of the second integration circuit Cbased on the bias current during the third period T. The amount of time from the start of the second period Tuntil the voltage of the first integration circuit Creaches the reference voltage Vth is detected, and the amount of time from the start of the third period Tuntil the voltage of the second integration circuit Creaches the reference voltage Vth is detected. The voltage of the first integration circuit Cis kept at the reference voltage Vth from when the voltage of the first integration circuit Creaches the reference voltage Vth until the start of the third period T, and the voltage of the second integration circuit Cis kept at the reference voltage Vth from when the voltage of the second integration circuit Creaches the reference voltage Vth until the start of the fourth period T. A pulse signal is generated, in which the pulse widths are equal to the amounts of time required for first and second integration circuits Cand Cto reach the reference voltage Vth.

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

Growing community of inventors

Neyagawa, Japan

Mamoru Sekiya