Abstract: A cut via is formed in an end of a multilayer circuit board of the first transmission line, and a clearance is provided between the cut via and a ground pattern for achieving an impedance matching between the first and second transmission lines. The cut via of a first transmission line which may be a stripline or a microstrip line, and an electrode of the second transmission line are connected to each other, and ground patterns of the first and second transmission lines are connected to each other. The first and second transmission lines have respective signal lines positioned substantially coaxially with each other.

Abstract: A magnetic sensor has a monotonic response to high-frequency magnetic strengths in a frequency range up to superhigh frequencies. The magnetic sensor includes a shielded loop coil having a triplate stripline structure. The shielded loop coil has one-turn looped ground patterns formed respectively in a first layer and a fifth layer and connected parallel to each other by a via, and has an inductance L. The one-turn looped ground patterns have end electrodes facing each other across gaps, one of the end electrodes including the via, providing a combined capacitor operable at high frequencies and having a capacitance C. The product L×C of the inductance L and the capacitance C is 2.5×10?20 or less and the maximum outer circumference length of the one-turn looped ground lines is 50 [mm] or less.

Abstract: An LED is an element in which when a voltage pulse applied to the intrinsic diode of an electrical equivalent model reaches a peak value, a current suddenly flows to obtain an optical output proportional to the forward current. By utilizing this property, the LED receives a rectangular voltage pulse having a large-current driving ability at a low output impedance, or a voltage pulse having two high levels. The low level of the voltage pulse is set within a voltage range where the extinction ratio of an output signal from the LED can be maintained. Even in an LED having a large internal capacitance, an increase in power consumption can be minimized, the transient response time can be shortened, high-speed modulation can be performed, and output light almost free from pulse waveform distortion can be obtained.

Abstract: A light-emitting diode driving circuit according to an embodiment of this invention includes a light-emitting diode, a first current switch circuit connected in series with the light-emitting diode, the first current switch circuit turning on/off a current in accordance with an external input signal input from an input terminal, a pulse current generating circuit connected in parallel with the first current switch circuit, the pulse current generating circuit supplying a pulse current including a pulse width smaller than the pulse width of the external input signal and shaping a leading edge portion of an optical waveform output from the light-emitting diode into a desired optical waveform, and a discharge circuit connected in parallel with the light-emitting diode, the discharge circuit quickly discharging charge stored in the light-emitting diode when the current to the first current switch circuit is turned off.

Abstract: A magnetic sensor has a monotonic response to high-frequency magnetic strengths in a frequency range up to superhigh frequencies. The magnetic sensor includes a shielded loop coil having a triplate stripline structure. The shielded loop coil has one-turn looped ground patterns formed respectively in a first layer and a fifth layer and connected parallel to each other by a via, and has an inductance L. The one-turn looped ground patterns have end electrodes facing each other across gaps, one of the end electrodes including the via, providing a combined capacitor operable at high frequencies and having a capacitance C. The product L×C of the inductance L and the capacitance C is 2.5×10−20 or less and the maximum outer circumference length of the one-turn looped ground lines is 50 [mm] or less.

Abstract: A reference voltage generating circuit 1 is provided for generating the stable reference voltage Vref against a variation in a supply voltage and an ambient temperature changes. A stabilized voltage generating circuit 2 is provided for generating the stabilized voltage Vg based on the reference voltage Vref. A voltage dividing circuit 4 divides reference voltage Vref. An amplifier circuit 5 amplifies an output voltage of the voltage dividing circuit 4. A current mirror circuit 6 is provided for outputting a current in the opposite direction of the output current of the amplifier circuit 5. A current-voltage conversion resistor 3 is connected between the output terminal of the stabilized voltage generating circuit 2 and the output terminal of the current mirror circuit 6. A buffer amplifier 7 supplies a current feedback type output amplifier circuit 8 with a voltage generated by the resistor 3.

Abstract: An optical semiconductor diode driver circuit, which is stably operable even with the supply of a source voltage slightly higher than the forward operation voltage of an optical semiconductor diode to be driven and can output switch current and voltage sufficient for driving the optical semiconductor diode, includes a pre-driver circuit operating as a limiting amplifier, and an output circuit responsive to a pulse-shaped voltage output from the pre-driver circuit and outputting a drive pulse current to the optical semiconductor diode as an external load. The output circuit is basically a type of the emitter-coupled amplifier which has either a differential configuration or a similar one to a Schmitt circuit and whose common-emitter loads are composed of a resistor and a variable constant current source to determine a amplitude of the output current pulse with small rise and fall times.

Abstract: A cut via is formed in an end of a multilayer circuit board of the first transmission line, and a clearance is provided between the cut via and a ground pattern for achieving an impedance matching between the first and second transmission lines. The cut via of a first transmission line which may be a stripline or a microstrip line, and an electrode of the second transmission line are connected to each other, and ground patterns of the first and second transmission lines are connected to each other. The first and second transmission lines have respective signal lines positioned substantially coaxially with each other.

Abstract: A reference voltage generating circuit 1 is provided for generating the stable reference voltage Vref against a variation in a supply voltage and an ambient temperature changes.

Abstract: A light-emitting diode driving circuit according to an embodiment of this invention includes a light-emitting diode, a first current switch circuit connected in series with the light-emitting diode, the first current switch circuit turning on/off a current in accordance with an external input signal input from an input terminal, a pulse current generating circuit connected in parallel with the first current switch circuit, the pulse current generating circuit supplying a pulse current including a pulse width smaller than the pulse width of the external input signal and shaping a leading edge portion of an optical waveform output from the light-emitting diode into a desired optical waveform, and a discharge circuit connected in parallel with the light-emitting diode, the discharge circuit quickly discharging charge stored in the light-emitting diode when the current to the first current switch circuit is turned off.

Abstract: An LED is an element in which when a voltage pulse applied to the intrinsic diode of an electrical equivalent model reaches a peak value, a current suddenly flows to obtain an optical output proportional to the forward current. By utilizing this property, the LED receives a rectangular voltage pulse having a large-current driving ability at a low output impedance, or a voltage pulse having two high levels. The low level of the voltage pulse is set within a voltage range where the extinction ratio of an output signal from the LED can be maintained. Even in an LED having a large internal capacitance, an increase in power consumption can be minimized, the transient response time can be shortened, high-speed modulation can be performed, and output light almost free from pulse waveform distortion can be obtained.

Abstract: A temperature dependent constant-current generating circuit includes a reference voltage generating circuit for generating a stable reference voltage against the power supply voltage and a temperature change, a stabilized voltage generating circuit for generating a stabilized voltage based on the reference voltage, a voltage divider for dividing the reference voltage, a common-emitter amplifier for amplifying an output voltage from the voltage divider, a current mirror circuit for outputting a current in a direction opposite to an output current from the amplifier, a current-to-voltage conversion resistor connected between the output terminal of the stabilized voltage generating circuit and the output terminal of the current mirror circuit, a buffer amplifier for receiving a voltage generated at the current input terminal of the resistor, and a current feedback output-stage amplifier driven by an output from the buffer amplifier.

Abstract: A peak hold circuit includes an error amplification circuit having a first transistor section receiving an input voltage and a second transistor section constituting a differential error amplifier together with the first transistor section. The second transistor section has a plurality of transistors connected in parallel so as to operate individually. The peak hold circuit also includes a switching circuit having a plurality of switching transistors operated in accordance with an operation voltage of each of the transistors of the second transistor section, a charging circuit including a capacitor, for charging the capacitor stage by stage in accordance with a switching operation of each of the switching transistors of the switching circuit, and an output circuit for outputting a charging potential of the capacitor as a peak value signal of the input voltage.

Abstract: There is provided an array device including functional circuits for a plurality of channels, constant current generating circuits for the plurality of channels for generating constant currents used to drive the functional circuits, respectively, in accordance with a control signal supplied from the outside, and a wiring for supplying therethrough the constant currents from the constant current generating circuits to the functional circuits, respectively, which are formed on an integrated circuit chip, wherein the constant current generating circuits provided so as to correspond to the channels are arranged concentratedly in a specific region on the integrated circuit chip, and the wiring is comprised of a common wiring extending from one terminal provided in the vicinity of the specific region to the vicinities of the constant current generating circuits.

Abstract: An optical receiving circuit comprises a photodetector, a differential transimpedance amplifier, a peak detector, a resistor network circuit and a discriminator. The transimpedance amplifier receives a current pulse converted by the photo-detector and outputs a non-inverting voltage signal and an inverting voltage signal of the same level. A peak detector for detecting a peak value of the non-inverting voltage signal. A resistor network circuit make an additional operations between an output signal from the peak detector and the inverted voltage signal, and between the non-inverting voltage signal and the non-inverting voltage signal, thereby generating two complemental voltage signals, which have the same amplitude and cross each other at a middle point of the amplitude.

Abstract: An optical interconnection capable of realizing smooth data transmissions among micro-processors provided on a plurality of processor boards. An optical interconnection includes: a series of optical devices, provided on the processor boards separately, each optical device on each processor board being connected with the processor elements provided on that processor board and including a multiplicity of optical element cells for intercepting light signals from a first side of the optical device, transmitting intercepted light signals to a second side of the optical device, and emitting light signals to the second side of the optical device; and an optical path for optically connecting the optical devices such that light signals coming from the second side of one optical device are intercepted at the first side of another optical device.

Abstract: An optical transmission apparatus of NRZ modulation system includes a laser driving circuit for deriving a current obtained by adding together an NRZ modulation signal, a D.C. bias, and a clock signal having an amplitude smaller than the bias, a semiconductor laser driven by the laser driving circuit, an optical fiber for transmitting a laser beam from the semiconductor laser to a reception side, a photodetector for detecting a laser beam on the reception side and converting the detected laser beam to an electrical signal, a data regenerating circuit for deriving an NRZ modulation signal from the detected electrical signal, and a clock extracting circuit for extracting the clock signal superposed on the NRZ modulation signal from the detected electrical signal.

Abstract: Disclosed herein is an optical interconnection device having a light source, a plurality of optical interconnecting elements, and a light-receiving element. The optical interconnecting elements are located on an output side of the light source. Each of the elements has first and second major surfaces and comprises an integral unit made of an optical semiconductor element and a grating lens having concentric annular grooves and concentric annular projections, and two electrodes formed on the first and second major surfaces, respectively. The optical semiconductor element and grating lens of each optical interconnecting element are formed on the first major surface, for emitting or receiving light. The light-receiving element is located on an output side of the optical interconnecting elements. The optical interconnecting elements are arranged at substantially regular intervals, each positioned such that the semiconductor element and the grating lens face to the same direction.