Fujitsu Corporation

Mariko Sugawara

Yukito Tsunoda

Satoshi Ide

Tetsuji Yamabana

A driving circuit for driving a diode includes at least one differential pair including a first output node and a second output node and configured to switch an output current, a current source configured to adjust the output current, a dummy load coupled to the second output node, a first termination resistor coupled between the first output node and a termination ground, and a second termination resistor coupled between the second output node and the termination ground. The output current is supplied to the diode through the first output node by at least one differential pair.

Driving circuit having a dummy load connected to one output node of a differential pair

A driver for shaping a drive signal includes a pre-emphasis circuit, an offset adjustment circuit, and an amplifier. The pre-emphasis circuit symmetrically emphasizes a rising edge portion and a falling edge portion of the drive signal. The offset adjustment circuit applies a direct-current offset to the drive signal. The amplifier amplifies the drive signal with the direct-current offset adjusted by the adjustment circuit. The amplifier has an input-output characteristic with a nonlinear portion. The offset adjustment circuit adjusts the direct-current offset so that the drive signal is amplified in the nonlinear portion.

Driver and optical transmission apparatus

There is provided an optical receiving device for deriving a signal using for data identification. The optical receiving device includes a demodulator for demodulating a modulated optical signal to an demodulated optical signal, a convertor for converting the demodulated optical signal to a first and a second electric signals, a generator for generating a complement signal by summing the first electric signal of a normal in phase component and the second electric signal of a reverse in phase component, and a suppressor for suppressing, by the use of the complement signal, a variation of potential which appears in a data signal at a time of phase changing of the modulated optical signal, the data signal being a difference of the normal in phase component and the reverse in phase component.

Optical receiving device, optical receiving circuit, and method for receiving optical signals

A semiconductor integrated circuit includes a cascode circuit having a transistor, a detector circuit and a bias generator circuit. A bias is applied to a substrate of the transistor. The detector circuit generates a signal related to a threshold voltage of the transistor. The bias generator circuit generates the bias based on the signal generated by the detector circuit.

Differential amplifier on semiconductor integrated circuit

There is provided a parallel-serial converter including a selector to convert parallel data to serial data, a flip-flop to which the serial data are input so as to latch the serial data, a generator to generate replica data simulating the serial data, a detector to detect a first switching point of the replica data and a second switching point subsequent to the first switching point, and a controller to control relative timings of timing converted to the serial data in the selector and timing when the serial data is latched in the flip-flop, based on the first switching point and the second switching point.

Parallel-serial converter

An amplifier circuit includes a first amplifier amplifying an input signal and outputting a first amplified signal, a second amplifier amplifying the first amplified signal and outputting a second amplified signal, and a feedback circuitry feeding back the second amplified signal to the input of the second amplifier. The feedback circuitry includes a feedback transistor that keeps the input level of the second amplifier constant.

Amplifier circuit

An amplifier circuit including: a multistage amplifier unit including an input-stage transistor and an output-stage transistor and configured to amplify an input signal and to output an amplified signal; and a feedback unit including a first feedback transistor, a second feedback transistor, and a feedback resistor, and configured to feed back the amplified signal to an input of the output-stage transistor in the multistage amplifier unit via the first feedback transistor, the second feedback transistor, and the feedback resistor.

Growing community of inventors

Kawasaki, Japan

Mariko Sugawara