Fujitsu Corporation

Fujitsu Microelectronics Limited

Kyocera Kinseki Corporation

Tomonari Morishita

Hideo Nunokawa

Suguru Tachibana

Fukuji Kihara

Tatsuo Kato

Makoto Kubota

Shunichi Ko

Naoto Emi

Miki T Suzuki

Hiroshi Ookawa

Even when, for example, electric charge is injected into the output transistor due to external factor such as a noise from the outside, to prevent the step-down voltage from rising, the step-down circuit is comprised of an N channel type output transistor which controls the voltage at the control end, a booster, which is connected to the control end of the output transistor and raises the voltage at the control end and a discharge circuit, which discharges the electric charge at the control end of the output transistor so that the power supply voltage inputted from the input end is stepped down to a desired step-down voltage and outputted from the output end.

Linear regulator with discharging gate driver

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 semiconductor device is disclosed including a current generator circuit that generates a first current substantially proportional to an absolute temperature, the first current being determined by a size ratio of a MOS transistor, and by a resistor; and a starting-up circuit that causes the current generator circuit to generate the first current at a stable working point of the current generator circuit, wherein while the current generator circuit operates at the stable working point, a current that flows through the starting-up circuit is determined by a diffusion resistance and a MOS transistor. When the current generator circuit starts operating at a stable operating point, resistance of the diffusion resistor and a MOS transistor connected in series determines a current that flows through a starting-up circuit. According to the above arrangements, the power consumption of the circuit can be reduced by increasing the resistance of the diffused resistor.

Growing community of inventors

Kawasaki, Japan

Tomonari Morishita