Sony Corporation

Sony Semiconductor Solutions Corporation

Katsuhisa Daio

Takeshi Yuwaki

Hayato Kamizuru

Osamu Maeda

Akihito Kamiegawa

Takahiro Arakida

Koichi Kobe

Tomoyuki Hiro

Masayuki Katakura

Hirofumi Nakano

Norio Shoji

Junkichi Sugita

Takehiro Taniguchi

Kimimasa Senba

Shouichi Kuroki

Masato Sekine

Masatoshi Kitada

Hiroyuki Shoubu

Takahiro Tsukada

Naoki Masumitsu

Provided is a light-emission driving device that includes a light-emission current detection unit, a phase difference detection unit, and a delay unit. The light-emission current detection unit detects a light-emission current for causing a light-emitting element to emit light, the light-emission current being supplied from a light-emission driving unit. The phase difference detection unit detects a phase difference between the detected light-emission current and a drive signal for controlling the supply of the light-emission current in the light-emission driving unit. The delay unit adjusts propagation delay of the drive signal in accordance with the detected phase difference, and supplies the adjusted drive signal to the light-emission driving unit as a drive signal.

Light-emission driving device and light-emitting device

A configuration of a light emission device that shortens a light emission latency time of a light emitting element is simplified. A light emission drive circuit includes a light emission current wire, a light emission current switch, a preliminary current wire, and a preliminary current switch. The light emission current wire flows a light emission current for causing a light emitting element to emit light, is the light emitting element. The light emission current switch is connected to the light emission current wire, and controls the light emission current. The preliminary current wire flows, in the light emission current wire, a preliminary current for exciting an inductance component of the light emission current wire before a light emission period being a period in which the light emission current flows in the light emitting element. The preliminary current switch is connected to the preliminary current wire, and controls the preliminary current.

Light emission drive circuit and light emission device

An abnormality of output laser light is detected for enhancement in safety. A light-source drive device includes a light-source control unit, a light-receiving unit, and an abnormality detection unit. The light-source control unit included in the light-source drive device controls light emission of a light source. The light-receiving unit included in the light-source drive device receives light from the light source through an output part allowing outward output of light of the light source. The abnormality detection unit included in the light-source drive device detects an abnormality of the light output from the output part, on the basis of the received light.

Light-source drive device and light-emitting device

The present invention relates to a driving device, a driving method, and a light-emitting unit that make it possible to appropriately drive a light-emitting element. The driving device according to the present invention includes: a setting section () that sets at least one of a bias current of a light-emitting element (an LD) or a target current for setting output light from the light-emitting element (the LD) to desired intensity on the basis of a result of detection of an offset light amount when the light-emitting element (the LD) does not emit light; and an output controller () that controls an output of a driving current of the light-emitting element (the LD) on the basis of at least one of the set bias current or the set target current. The detection of the offset light amount is performed by a light-receiving element (a PD) that receives a portion of the output light. The present invention is applicable to a ranging module, for example.

Driving device, driving method, and light-emitting unit

A correction circuit includes a correction section configured to superpose a second current pulse on a first current pulse, and thereby correcting a waveform of the first current pulse, the first current pulse being output from a current source configured to drive a surface-emitting semiconductor laser in a pulsed manner, the correction section being configured to allow the second pulse to have a waveform obtained through attenuating a crest value of the second current pulse with time, increasing an initial crest value of the second current pulse by an amount that is larger as magnitude of the first current pulse is larger, and allowing the amount by which the initial crest value is increased to be smaller as ambient temperature of the semiconductor laser is higher, and being configured to output the second pulse having the waveform.

Correction circuit, drive circuit, light emission unit, and method of correcting current pulse waveform

A driving device includes: a driving circuit configured to provide a drive current; a first detecting circuit; a second detecting circuit configured to detect a first reference current or a physical quantity corresponding thereto, as well as a second reference current or a physical quantity corresponding thereto; a first generating circuit configured to generate an additive voltage as a control voltage at a light-emission time of a light-emitting element, and further to generate a second voltage as a control voltage at a non-light-emission time of the light-emitting element; and a second generating circuit configured to generate a third reference current. The second detecting circuit has a first adder circuit that generates the first reference current by adding the second reference current and the third reference current with each other.

Driving device and light-emitting unit

A drive circuit and a drive current correcting method are described herein. The drive circuit comprises a current source that outputs a drive current, and a correction circuit that outputs a correction current. The correction circuit includes a first RC time constant circuit. An output terminal of the current source is connected to an output terminal of the correction circuit.

Correction circuit, drive circuit, light-emitting device and correction method of current pulse waveform

A correction circuit is provided, which may reduce dullness of a light output waveform due to wavelength detuning. The correction circuit includes an RC time constant circuit. The RC time constant circuit is used to correct a waveform of a current pulse outputted from a current source, the current source driving a surface-emitting semiconductor laser in a pulsed manner, so that a pulse waveform of light output of the semiconductor laser is approximately a rectangle.

Correction circuit, drive circuit, light emitting device, and method of correcting current pulse waveform

Disclosed herein is a laser driver including a light emission controlling section configured to stop generation of a control voltage by a control voltage generating section, causing a given voltage corresponding to a magnitude of a reference current to be outputted to an input node of a first emitter follower to operate the first emitter follower for a first time period from start of a light emission time period, release stop of the generation of the control voltage by the control voltage generating section, causing the control voltage to be outputted to the input node of the first emitter follower to operate the first emitter follower until end of the light emission time period of the laser, and operate a second emitter follower to discharge electric charges accumulated in the laser for a second time period after the end of the light emission time period of the laser.

Laser drive

A gain control circuit to determine gain by a current ratio of mutual conductance. The gain control circuit includes a first gain control circuit in which positive and negative phase input signals are supplied, gain is changed based on a first control signal, and positive and negative phase output signals are outputted, a second gain control circuit in which the positive and negative phase input signals are supplied, gain is changed based on a second control signal, and the positive and negative phase output signals are outputted, and a load circuit in which the positive phase output signal of the first gain control circuit and the negative phase output signal of the second gain control circuit are synthesized and supplied to a first input terminal, and the negative phase output signal of the first gain control circuit and the positive phase output signal of the second gain control circuit are synthesized and supplied to a second input terminal, and the synthesized signals are lead out through mutual conductance.

Gain control circuit and optical recording and reproducing device using thereof

The present invention provides an amplifier circuit comprising a differential amplifier and a negative feedback loop circuit, in which a positive feedback loop circuit having a gain smaller than a gain of the negative feedback loop circuit is formed inside the negative feedback loop circuit.

Amplifier circuit

A gain adjustment circuit includes a gain varying device for varying the gain of an input signal; and a detection device for detecting a variable output signal of the gain varying device, wherein the detection output signal of the detection device is fed back to the gain varying device.

Gain adjustment method, gain adjustment circuit, and optical disc device having same gain adjustment circuit

An asymmetry detection circuit having a simple circuit configuration capable of realizing reliable detection without dependence on the signal level and capable of realizing high precision asymmetry detection almost completely free of any influence from a voltage offset or the like, and a detection method of same, wherein a capacitor cuts off the direct current component of an input signal and passes the alternating current component, a bias voltage is added to the alternating current component in accordance with a constant voltage of a constant voltage source to generate an APL clamp signal, a comparator compares the signal with a constant voltage and outputs a pulse voltage signal representing a duty ratio of the signal in the APL value, a voltage/current conversion circuit outputs a current signal to charge or discharge a capacitor to generate an integrated signal, and a filter eliminates the alternating current component of the integrated signal and outputs the direct current component as an asymmetry detection signal.

Asymmetry detection circuit and detection method of same

A nonlinearity compensation circuit is disclosed which includes an inverse hyperbolic function generation circuit for converting differential currents corresponding to input signals in&plus; and in&minus; into differential voltages which increase in proportion to an inverse hyperbolic function, an offset provision circuit for providing an offset corresponding to control signals c&plus; and c&minus; to the differential voltages outputted from the inverse hyperbolic function generation circuit and a hyperbolic function generation circuit for converting the differential voltages to which the offset has been provided by the offset provision circuit into signals which increase in proportion to a hyperbolic function and outputting the resulting signals as output signals out&plus; and out&minus;. Consequently, compensation for the nonlinearity such as second order distortion can be performed for the read signal from a recording medium.

Nonlinearity compensation circuit and method, control circuit and method for nonlinearity compenstation circuit and recording and/or playback apparatus employing the same

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Kagoshima, Japan

Katsuhisa Daio