Hitachi, Ltd.

Osamu Matsubara

Toshiro Suzuki

Tadahiro Yamaguchi

Hiroshi Takatori

Hiroaki Nakashima

Hiroshi Kuwaki

Izuru Yamada

Yoshihiro Yano

Optical transmission equipment

A pulse generating circuit is provided for generating a pulse having a time width synchronized with an input pulse and corresponding to a reference voltage. The circuit is particularly designed not to be affected by parasitic capacitance. A circuit for charging one electrode of an integrating circuit with a constant current is controlled by turning on or off a switch in response to the input pulse. The other electrode of the integrating capacitor is connected with a reference voltage source by driving a switch in response to a pulse having a pulse width which contains the time period of the input pulse and which is wider than the input pulse. A comparator is provided for comparing the potential at one electrode of the integrating capacitor and ground potential. A desired pulse is generated by a logic circuit which is receives both the output of the comparator and the input pulse.

Pulse width generating circuit synchronized with clock signal and

For realizing a stabilized current source circuit providing a stabilized current which is insensitive to a change in the threshold voltage of a MOS transistor, a gate electrode of a first MOS transistor feeding a drain current as a constant current output is supplied with the sum of the gate-source voltage of a second MOS transistor and the potential of a stabilized voltage source.

Stabilized current source circuit

Growing community of inventors

Kokubunji, Japan

Osamu Matsubara