Kabushiki Kaisha Toshiba

Shinsuke Fujii

Hiroyuki Shibayama

Ryota Terauchi

Shinji Nakatsuka

Takuma Aoyama

According to an embodiment, a transmission circuit is configured to transmit a signal to a reception circuit through a transmitting AC coupling element. The reception circuit receives a signal through a receiving AC coupling element. The transmitting AC coupling element is AC coupled to the receiving AC coupling element. The transmission circuit includes a drive signal generation circuit and a drive circuit. The drive signal generation circuit is configured to generate a drive signal in synchronization with a transmission signal to be transmitted. The drive circuit is configured to cause, in response to the drive signal, a drive current to flow through the transmitting AC coupling element in synchronization with a rising edge and a falling edge of the transmission signal during a driving period set in advance.

Transmission circuit, reception circuit and communication system

According to an embodiment, a transmission circuit is configured to transmit a signal to a reception circuit through a transmitting AC coupling element. The transmitting AC coupling element is AC coupled to a receiving AC coupling element. The transmission circuit includes a drive signal generation circuit and a drive circuit. The drive signal generation circuit is configured to generate a drive signal in synchronization with a transmission signal to be transmitted. The drive circuit is configured to cause, in response to the drive signal, a drive current to flow between both ends of the transmitting AC coupling element in synchronization with a rising edge and a falling edge of the transmission signal during a driving period set in advance. The drive circuit is configured to apply an applied voltage to both of the ends of the transmitting AC coupling element after the driving period.

AC coupled transmission circuit and system

According to an embodiment, a reception circuit is configured to receive a reception signal from a transmission circuit through a receiving AC coupling element. The transmission circuit transmits a transmission signal through a transmitting AC coupling element. The receiving AC coupling element is AC coupled to the transmitting AC coupling element. The reception circuit includes a variable gain amplifier, a hysteresis circuit and a first control circuit. The variable gain amplifier is configured to amplify the reception signal with a variable gain to output an amplified signal. The hysteresis circuit has hysteresis in an input/output characteristic, and is configured to output an output signal according to the amplified signal. The first control circuit is configured to control the gain so that an amplitude of the amplified signal approximates a reference amplitude.

Reception circuit and communication system

The input circuit includes a first switch control circuit that controls a first switch and a second switch. The first switch control circuit turns off the first switch and the second switch in a first period during which a first input signal and a second input signal are DC signals. The first switch control circuit turns on the first switch and the second switch in a second period during which the first input signal and the second input signal are AC signals.

Input circuit

According to an embodiment, a communication system includes a transmitting electrode, a first transmission line, a transmission circuit, a receiving electrode, a second transmission line and a reception circuit. The first transmission line includes one end connected to the transmitting electrode. The transmission circuit is connected to an other end of the first transmission line and configured to transmit a transmission signal. The receiving electrode is capacitively coupled to the transmitting electrode. The second transmission line includes one end connected to the receiving electrode. The reception circuit is connected to an other end of the second transmission line and configured to receive a reception signal via the receiving electrode and the second transmission line. Characteristic impedances of the first transmission line and the second transmission line are greater than an output impedance of the transmission circuit.

Communication system and transmitter

According to an embodiment, a reception circuit receives a reception signal according to a signal transmitted from a transmission electrode through a reception electrode capacitively coupled to the transmission electrode. The reception circuit includes an adder, a hysteresis circuit, a shift register and a feedback signal generator. The adder is configured to add one or more feedback signals to the reception signal. The hysteresis circuit has hysteresis in input and output characteristics, and is configured to output output data according to an output signal of the adder. The shift register is configured to sequentially shift the output data of the hysteresis circuit. The feedback signal generator is configured to generate the feedback signal according to each output data of the shift register.

According to an embodiment, a variable gain amplifier includes a differential transistor pair including a first and second transistor. A variable resistor for setting a gain is connected between electrodes the transistor pair. A first variable capacitor is connected to an electrode of the first transistor, and a second variable capacitor is connected to an electrode of the second transistor. Corresponding to the gain setting set by adjusting the variable resistor, capacitance values of the variable capacitors can be adjusted to provide improved frequency characteristics of the variable gain amplifier.

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Yokohama Kanagawa, Japan

Shinsuke Fujii