Fujitsu Corporation

Kyocera Kinseki Corporation

Fukuji Kihara

Tomonari Morishita

Suguru Tachibana

Hideo Nunokawa

Makoto Kubota

Yuki Kaneko

Shunichi Ko

Hiroshi Ookawa

An object is not only to contribute to reduction in current consumption but also to advance actuation of a system required in a camera, an on-vehicle electric component, etc. by shortening a waiting time for stabilization of oscillation. An oscillator having an inverting amplifier inverting and amplifying an input signal and outputting it, a resonator connected to between an input and an output terminals of the inverting amplifier, a feedback resistance connected in parallel to the resonator, and an output circuit outputting a first clock signal based on a signal of an on-load parallel resonance frequency or a parallel resonance frequency oscillated by the resonator, the inverting amplifier and the feedback resistance to a function block is provided.

Oscillator and semiconductor device

A semiconductor device in which a dielectric breakdown of a gate oxide in a MOS capacitor can be prevented and in which a circuit area can be reduced. The semiconductor device comprises an NMOS transistor a gate of which is connected to a terminal VDD on a high potential side and a PMOS transistor a gate of which is connected to a terminal GND on a low potential side, source/drain (S/D) regions of the NMOS transistor and source/drain (S/D) regions of the PMOS transistor being electrically connected.

MOS capacitor device

A crystal oscillation circuit has a reduced circuit area and enables to stably oscillate at low consumed current. The crystal oscillation circuit includes an oscillating amplifier and a constant voltage generator. The oscillating amplifier excites a resonator composed of a resistor, a crystal oscillator and a capacitor. The constant voltage generator includes a one-stage differential circuit composed of a transistor and a capacitor for suppressing transient fluctuation of a constant voltage Vreg for generating the constant voltage Vreg served as a supply voltage for the oscillating amplifier. By generating the constant voltage Vreg through the one-stage differential circuit, the phase lag of the constant voltage Vreg reaches 90 degrees at most. This eliminates the necessity of a phase compensation capacitor, resulting in making the circuit area smaller and realizing the stable oscillation at low consumed current.

Crystal oscillation circuit

A level conversion circuit for converting a first signal at a lower power source side into a second signal at a higher power source side, which is higher than the lower power source, includes first and second transistors provided at a ground side and controlled by the first signal and an inverted signal there of; third and fourth transistors gates and drains of which are cross-connected, provided at the higher power source side and connected to the first and second transistors respectively; and an initialization circuit for, at a higher power voltage rise time, reducing (or raising), along a current path, a level of either a first node located between the first and third transistors, or a second node located between the second and fourth transistors, to a ground voltage (or to a voltage of the higher power source).

Growing community of inventors

Kawasaki, Japan

Fukuji Kihara