Rohm Co., Ltd.

Makoto Murata

Isamu Nishimura

Shinichi Saitoh

Yoko Nomaguchi

Shizuka Yokoi

The present invention provides an optical semiconductor device for improving minimization and increase of detection precision. An optical semiconductor device Aof the present invention includes: a substrateincluding a semiconductor material, and including a main surfaceand a back surfacea semiconductor light-emitting elementA at the substrate; a semiconductor light-receiving elementB at the substrate; a conductive layerconducting the semiconductor light-emitting elementA and the semiconductor light-receiving elementB; and an insulating layerbetween at least a portion of the conductive layerand the substrate; wherein the substrateincludes a recessrecessed from the main surfaceand including a bottom surfaceA of a light-emitting side recess where the semiconductor light-emitting elementA is disposed, and a bottom surfaceB of a light-receiving side recess where the semiconductor light-receiving elementB is disposed; a light-emitting side transparent portionA for light from the semiconductor light-emitting elementA to pass through the bottom surfaceA of the light-emitting side recess to the back surfaceand a light-receiving side transparent portionB for light from the back surfaceto pass through the bottom surfaceB of the light-receiving side recess to the semiconductor light-receiving elementB.

Optical semiconductor device

A transmitter includes a voltage conversion circuit converting supply voltage externally supplied into drive voltage and outputting the drive voltage; and an optical output unit which is supplied with the drive voltage and outputs an optical signal, wherein the voltage conversion circuit and the optical output unit are included in a same module.

Transmitter and information processing device converting supply voltage to drive voltage

The clock generator of this invention saves a buffer memory for the data transfer interface, which has conventionally been required, when using a spectrum spread clock in circuits and devices inside a system. The clock generator can easily be applied as the operational clock in a system, and enhances the performance of the system. In the clock generator, the variable delay circuit controls the phase of the reference clock generated by an oscillator. The delay setting circuit is able to vary the setting of the control voltage to the variable delay circuit at each clock cycle, and modulates the phase of the reference clock. The phase modulation means of the delay setting circuit fluctuates the cycle of the output modulation clock to thereby spread the spectrum. Also, the delay setting circuit detects the output states (edges of the clock) of delay elements of the variable delay circuit, and confines the phase difference of the reference clock and the modulated clock within a specified range (for example, half the cycle of the reference clock). Thereby, the clock generator guarantees a certain extent of synchronization in the spectrum spread clock.

Clock generator

A first receiving terminal and a second receiving terminal are connected to a first signal transmission line and a second signal transmission line, respectively, and receive the input of transmission signals. A first resistor and a second resistor convert current signals contained in the transmission signals into voltage. A comparator inputs the respective voltages converted by the first and the second resistor, and outputs, as an output signal, a voltage corresponding to a difference between their voltages. A first transistor connected to an end of the first resistor and a second transistor connected to an end of the second resistor reduce the variation in a transmission voltage signal due to the variation in the current signals contained in the transmission signals. A third transistor connected to the other end of the first resistor causes to drop power-supply voltage so as to generate a control signal. The control signal is turned into a gate voltage of the second transistor in a crosswise manner. A fourth transistor connected to the other end of the second resistor operates in the similar manner to the third transistor.

Receiving apparatus and transmission apparatus utilizing the same

An electronic appliance, in addition to being of the type that is connected to another electronic appliance by way of a signal line and that permits the other electronic appliance to recognize establishment of connection between them on the basis of the voltage level on the signal line, allows this voltage level to be varied with the signal line kept connected. A signal terminal for connecting the signal line and a supplied-power line for supplying a voltage having a predetermined level are connected through a pull-up resistor and a transistor connected in series. The transistor is controlled by a controller so that, even after the electronic appliance starts receiving electric power, the transistor will be kept in a non-conducting state and thus the voltage on the supplied-power line will not be supplied to the signal terminal until the operation of various portions of the electronic appliance has been stabilized. The transistor may be controlled by being fed with a control signal from the outside.

Growing community of inventors

Kyoto, Japan

Makoto Murata