Mitsubishi Denki Kabushiki Kaisha

Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Renesas Technology Corp.

Mitsubishi Denki Kabushiki Kasiha

Hanshin Electric Co., Ltd.

Hiroshi Kimura

Yoshinori Tanaka

Shinichi Satoh

Hiroji Ozaki

Wataru Wakamiya

Kazuko Nishimura

Takahisa Eimori

Kazutami Arimoto

Kazuyasu Fujishima

Tadashi Nishimura

Tadato Yamagata

Takahiro Tsuruda

Kazuo Tomita

Akira Matsuzawa

Yutaka Abe

Ryoji Nishiyama

Hideaki Katashiba

Mitsuie Matsumura

Tsuneo Yumikura

Masahiro Higuchi

Shigenori Sakamori

Joji Hayashi

Yuusuke Yamaoka

Masaki Ikeuchi

Akira Doi

Yoshiaki Akase

Shigeki Furuya

Ryangsu Kim

Chika Hirai

Yoshitaka Kurisu

Kazunao Sato

Yukihiro Hosaka

Kazuyuki Aiba

Hidesato Horil

Tomoko Masuda

Rei Takada

Masakatsu Mukae

Koichi Ohata

Tadaaki Nakano

A ramp wave output circuit includes a ramp wave generation circuit generating a ramp wave, and a low-pass filter having a variable cutoff frequency, which receives the ramp wave. The low-pass filter operates at a first cutoff frequency for a predetermined time period after the receipt of the ramp wave, and at a second cutoff frequency, which is larger than the first cutoff frequency, after the predetermined time period has passed.

Ramp wave output circuit, analog/digital conversion circuit, and camera

A solid-state imaging device includes pixels, arranged in a matrix, each of which converts light into a signal voltage. The solid-state imaging device also includes column signal lines, each of which is provided for corresponding one of columns, so that the signal voltage is provided to corresponding one of the column signal lines. Additionally, the solid-state imaging device includes AD converting units, each of which is provided for the corresponding one of the column signal lines, and is configured to convert the signal voltage into a digital signal. Each of the AD converting units includes a comparing unit generating an output signal indicating a greater voltage of the signal voltage and a reference voltage, and a counting unit counting a count value until logic of the output signal is inverted The solid-state imaging device further includes a suspending unit suspending power supply to the comparing units after the logic of the output signals is inverted.

Solid-state imaging device including A/D converting circuit with power-down controller

An optical transmission circuit includes a light emitting device () having different temperature characteristics at low temperature and high temperature (e.g., a VCSEL (Vertical Cavity Surface Emitting Laser), differential switch transistors (M, M) for driving the light emitting device (), the differential switch transistors having sources connected to each other and drains connected to the light emitting device () and a power supply, respectively, a bias current source () for causing a bias current to flow, a modulated current source () for causing a modulated current to flow, and a temperature compensation current source () for controlling currents of the bias current source () and the modulated current source () so as to compensate for both temperature characteristics at low temperature and temperature characteristics at high temperature of the light emitting device ().

Optical transmission circuit

First and second envelope detector circuits have, respectively, a resistance row, a capacitative element connected to the resistance row in parallel and a transistor connected between a connection point between the resistance row and the capacitative element and a predetermined voltage node. An output of a level shifter is supplied to a gate or a base of the transistor of the first envelope detector circuit. A predetermined voltage is supplied to a gate or a base of the transistor of the second envelope detector circuit. A detector detects an intermediate terminal voltage of the resistance row of the first envelope detector circuit with reference to a total voltage or an intermediate terminal voltage of the resistance row of the second envelope detector circuit.

High frequency power detector circuit and radio communication device

A light emitting element driving differential switch () includes first and second transistors (M, M). A third transistor (M) is connected as an auxiliary switch in parallel to the first transistor (M) whose drain is connected to a light emitting element (). A third switch driving signal (IN) is input to the third transistor (M) to turn ON the third transistor (M) at a slightly earlier point in time than when complementary switch driving signals (IN, IN) are input to the first and second transistors (M, M) to drive the first and second transistors (M, M). This improves the rising characteristics of the output from the light emitting element having a high power level.

Optical transmitter circuit

A receiving circuit comprises a transimpedance amplifierincluding an inversion amplifierfor amplifying an input current IN, and a feedback resistance Rconnected between an input and an output of the inversion amplifier, a comparison circuitfor comparing an output OUT of the transimpedance amplifierwith a certain desired reference value, and outputting a result of the comparison, and a control circuit for holding the comparison result, and generating an AGC signalfor adjusting a gain of the transimpedance amplifier. The transimpedance amplifierhas a function capable of gain adjustment in accordance with the input AGC signal. The control circuitperforms gain adjustment until the output OUT of the transimpedance amplifierexceeds the reference value so that an appropriate gain is obtained. Therefore, even when an input has a wide dynamic range, it is possible to prevent signal saturation and a distortion in output waveform in the transimpedance amplifier, so that appropriate reception can be invariably performed and a signal having a stable duty can be output.

Receiving circuit and optical signal receiving circuit

An optical receiver preamplifier includes an inverting amplifierand a current-voltage conversion elementconnected between input and output terminals of the inverting amplifier. The inverting amplifierincludes a first transistorhaving a gate connected to the input terminal In of the inverting amplifier, a second transistorhaving a source connected to a drain of the first transistorand a gate to which a predetermined voltage Vb is applied, and a loadconnected to a drain of the second transistor. A third transistoris connected between the input terminal In of the inverting amplifierand a source of the second transistor

Optical receiver preamplifier

The current-voltage converting circuit converts an input current signal into a voltage signal, and the single-differential converting circuit converts the voltage signal into differential signals so as to output the differential signals. The first and second low-pass filters input outputs from the single-differential converting circuit, respectively, and the voltage-current converting circuit converts a difference between the output voltages from the first and second low-pass filters into a current signal. The current-voltage converting circuit inputs a voltage held in the hold capacitor as a control signal and converts the input current signal into a voltage signal using a current-voltage converting gain according to the control signal.

Optical receiving circuit

A differential amplifier according to the present invention comprises, in addition to a differential amplifier circuit and an output-stage amplifier circuit, a first source follower circuit for buffering a first output signal of the differential amplifier circuit, a second source follower circuit for buffering the first output signal of the differential amplifier circuit, and a source ground amplifier circuit, to a source of which an output terminal of the second source follower circuit is connected, and driven by a second output signal of the differential amplifier circuit, wherein a first-polar transistor in the output-stage amplifier circuit is driven by an output signal of the first source follower circuit, and the second-polar transistor is driven by an output signal of the source ground amplifier circuit.

Differential amplifier

Included are a light-emitting circuit having a laser diode (LD); an LD drive circuit for driving the light-emitting circuit; a bias circuit for adding a bias current to a pulse current outputted from the LD drive circuit; a light-receiving circuit for receiving monitoring light outputted from the light-emitting circuit; an I/V conversion circuit for subjecting an output from the light-receiving circuit to current-to-voltage conversion; a maximum-value detection circuit and an average-value detection circuit for respectively detecting the maximum and minimum values of an output voltage of the I/V conversion circuit; a first comparator for comparing the detected maximum value with a first reference value to feed back the comparison result to the LD drive circuit; and a second comparator for comparing the detected average value with a second reference value to feed back the comparison result to the bias circuit.

Laser diode driver with extinction ratio control

In a reference voltage generating circuit, in a first period, only a first switch is OFF and a maximum peak value Vmax of an input signal In is held at a node A of a first capacitor . Next, in a second period, a second and a third switches are opened, and a voltage difference between the maximum peak value Vmax and a minimum peak value Vmin is held at a node C of a capacitor string. At this time, the voltage held in a second capacitor of the capacitor string is added to the voltage held in the first capacitor, and the voltage at a node B is output as a reference voltage Vref. The input signal In is applied to one input terminal of a differential amplifying circuit, and the reference voltage Vref is applied to the other input terminal. When the voltages held at the nodes A and C have stabilized, the reference voltage Vref is generated. Accordingly, there is provided a voltage amplifier that can amplify input signals having a variety of signal amplitudes to a constant amplitude by using the reference voltage generating circuit with excellent high-speed response.

Reference voltage generating circuit and voltage amplifier using the same

A conductive layer contact structure is provided, in which a contact hole of a diameter smaller than the resolution of photolithography technique is formed in a stabilized manner by an etching with low aspect ratio, the contact resistance regarding a conductive layer formed through this contact hole is low, and the step coverage of the conductive layer is satisfactory such that it is not electrically short-circuited with other conductive layers. A silicon oxide film and a silicon nitride film are formed on a gate electrode as first insulation layers. A silicon oxide film is formed as a second insulation layer having a high etching selectivity with respect to the silicon nitride film provided as an upper insulation layer of the first insulation layer. Reaching a surface of an n diffused layer formed at a surface of a silicon substrate as a conductive region, a contact hole is formed. A sidewall spacer is formed at the inner sidewall of the silicon oxide film defining a hole. Due to this sidewall spacer, the contact hole having a diameter smaller than the resolution of photolithography technique is defined by the inner sidewall of the silicon oxide film and silicon nitride film.

Semiconductor device with conductive contact layer structure

A laser driver including a current-output-controlling switch; output-current-generating transistor; current-to-voltage converting transistor; first and second current sources; and current path selector having an input terminal and first and second output terminals. Responsive to a control signal, the selector outputs current through one of these two output terminals. The output current of the second current source is supplied to the current path selector. The output current supplied from the current path selector through the second output terminal thereof and the output current of the first current source are input to the current-to-voltage converting transistor. The output voltage of the current-to-voltage converting transistor is applied between the gate and source of the output-current-generating transistor. Then, the current is output through the drain of the output-current-generating transistor and the current-output-controlling switch.

Laser driver and optical transceiver

A laser driver according to the present invention is adapted to keep the optical output power of a laser diode constant even if the temperature has changed or if the performance of the laser diode has deteriorated with time. The laser driver includes a photodiode, a current-to-voltage converter, a reference voltage generator, a transconductor, a holding capacitor and a drive current output circuit. The current-to-voltage converter converts an output current of the photodiode, which is provided to monitor the optical output of the laser diode, into a monitor voltage. The transconductor supplies an output current corresponding to a difference between the monitor voltage and a predetermined reference voltage. The drive current output circuit outputs a laser drive current corresponding to the voltage held by the holding capacitor, which is connected to the output terminal of the transconductor. The laser driver with this configuration performs a feedback control in such a manner as to equalize the monitor voltage with the reference voltage, thereby keeping the optical output power of the laser diode constant. As a result, high-precision and stabilized APC performance is realized.

In a preamplifier for optical receivers, the input of an inverting amplifier is connected to an input terminal, the output of the inverting amplifier is connected to the gate of a first transistor, the source of the first transistor and the source of a second transistor are connected to a first bias member, the drain of the first transistor and the gate of the second transistor are connected to a first load member, the drain of the second transistor is connected to a second load member and an output terminal, and a feedback resistor is connected between the input and output terminals. With this configuration, a stable, low-power, wide-band transimpedance amplifier is provided without the necessity of special phase compensation.

Growing community of inventors

Hyogo, Japan

Hiroshi Kimura