Hitachi, Ltd.

Hitachi Automotive Engineering Co., Ltd.

Hitachi Koki Co., Ltd.

Hitachi Automotive Engineering, Ltd.

Masayoshi Suzuki

Masahiro Matsumoto

Takao Sasayama

Seiko Suzuki

Norio Ichikawa

Yukiko Sugisawa

Keiji Hanzawa

Masayuki Miki

Junichi Horie

Tatsuya Kamei

Shinzi Okuhara

Masuo Akamatsu

Jun-ichi Ohwada

Akio Sagawa

Keizi Hanzawa

Yuuji Ogasawara

Yoshiharu Nagae

Motohisa Funabashi

Hiroshi Sato

Sadayasu Ueno

Masaaki Kitajima

Hideaki Kawakami

Yasumasa Matsuda

Tetsuo Ito

Masaru Takabatake

Ichiro Ohhinata

Korefumi Tashiro

Kenkichi Suzuki

Shigeki Tsuchitani

Kanemasa Sato

Tomoyuki Tanaka

Masanori Kubota

Syoji Sagae

Keisuke Bekki

Masaaki Kitazima

Hiromichi Ebine

Masao Adachi

Yoshikazu Hosokawa

Fumio Wakamori

Masatoshi Kasahara

Yasuhiro Asano

Tetsuo Matsukura

Naoyuki Izaki

Hirokazu Fujita

Hidesato Horii

Toshiyuki Noma

A capacitance acceleration sensor and method of making same are disclosed. A capacitance acceleration sensor includes a movable electrode etched from a silicon plate which is clamped between two solid dielectric plate members of glass, silicon oxides, or oxygen oxides. Static electrodes are secured to surfaces of the dielectric members facing opposite the movable electrode, thereby providing easy manufacturing assessibility for leadout wires from these electrodes. In certain embodiments, the movable electrode is formed integrally with a monocrystalline silicon plate member which also contains an integrated circuit for generating an output acceleration signal in response to movement of the movable electrode when the assembly experiences acceleration forces.

Method of making a capacitance type acceleration sensor

A capacitance detector comprises switches for charging and discharging a sensing part, an integrator constituted by a condenser and an operational amplifier for integrating a charging current or a discharging current which is generated according to the charging and discharging the sensing part, a switch for charging an output voltage of the operational amplifier and for feedbacking an electric charge to the integrator, and a condenser. The capacitance detector can be provided by the operational amplifier having a low response performance and a small output current and no hold sample circuit, thereby a circuit scale of the capacitance type sensor can be made small.

Capacitance type sensor device

A capacitance acceleration sensor includes a movable electrode etched from a silicon plate which is clamped between two solid dielectric plate members of glass, silicon oxides, or oxygen oxides. Static electrodes are secured to surfaces of the dielectric members facing opposite the movable electrode, thereby providing easy manufacturing assessibility for leadout wires from these electrodes. In certain embodiments, the movable electrode is formed integrally with a monocrystalline silicon plate member which also contains an integrated circuit for generating an output acceleration signal in response to movement of the movable electrode when the assembly experiences acceleration forces.

Capacitance type acceleration sensor

A testing method is provided for a semiconductor device which includes a control terminal and a pair of main terminals wherein one of the main terminals is isolated from the outside by a dielectric. First, a voltage which changes with time is applied to the isolated main terminal through the dielectric. A control signal which controls conduction and non-conduction of the semiconductor device is the applied to the control terminal. Following this, the test is made by detecting a displacement current flowing through at least one of the two main terminals and the control terminal.

Method for testing an on-off function of semiconductor devices which

An apparatus for diagnosing the characteristic of an acceleration sensor and a method for diagnosis thereof are disclosed. The acceleration sensor includes a movable electrode (or mass part) displaced in accordance with an acceleration and a fixed electrode disposed opposite to the movable electrode. In a diagnosis mode, a signal for diagnosis is applied to the fixed electrode so that an electrostatic force as a force corresponding to a predetermined acceleration is generated between the fixed electrode and the movable electrode. In the case where the acceleration sensor is sound, the movable electrode or mass part is normally displaced. A failure of the acceleration sensor, the deterioration thereof in performance, a change in characteristic thereof caused from the lapse of time, or the like is self-diagnosed by detecting a change in capacitance between the movable electrode and the fixed electrode upon generation of the diagnosis signal. The force corresponding to the predetermined acceleration may be an electromagnetic force or a mechanical oscillation based on a piezoelectric element.

System and method for diagnosing characteristics of acceleration sensor

An air bag operation device which employs only one CPU module to guarantee sufficient fail-safety in the operation of the air bag without increasing the scale of the hardware. A plurality of crash-discriminating programs of different versions and a plurality of self-diagnosing programs of different versions are executed by a single CPU module, a signal is fed to an air bag igniting device based upon a comparison of the discriminated results by the plurality of crash-discriminating programs, and a signal is fed to an abnormality alarm device based upon comparison of the discriminated results of the plurality of self-diagnosing programs.

Air bag operation device

A semiconductor acceleration sensor is formed by a cantilever having a conductive movable electrode of predetermined mass at one end, at least one pair of fixed conductive electrodes which are stationary with respect to the movable electrode located on opposing sides of the movable electrode, and gaps provided between the movable electrode and the fixed electrodes. To prevent the movable electrode becoming fused to the contacted fixed electrode, in a first aspect of this invention, an insulating layer is provided between the movable electrode and fixed electrodes, the layer being either on the movable electrode or on the fixed electrodes and in a second aspect the movable electrode or, preferably, the fixed electrodes, are formed of a high melting point material. In such a second aspect, to improve adhesion between the high melting point material and a substrate to which the fixed electrodes are mounted, a lower melting point material is firstly coated on the substrates. A sensor detector unit processing circuit has the output characteristic of the circuit digitally adjusted by suitable switching of a plurality of resistors, and the sensor chip and the detector unit integrated circuit may be located on a common base and mounted in a hermetically sealed chamber to prevent adverse environmental effects affecting operation of the sensor and detector unit assembly. A gas having a dew point of -40.degree. C. or lower is, advantageously, charged into the hermetically sealed chamber.

Semiconductor acceleration sensor and vehicle control system using the

The present specification discloses a hot wire air flow meter with high circuit stability. The hot wire type air flow meter comprises a hot wire located in an air flow path to be measured and to which current is supplied from the external, a circuit for detecting a value of current flowing through the hot wire, an amplifying circuit including an inverting input terminal, a non-inverting input terminal to which a value detected in the current detecting circuit is applied, and an output terminal to which an output of an air-flow function is applied, a feedback circuit for supplying a feedback output to any terminal except the non-inverting input terminal of the amplifying circuit and controlling the output of the amplifying circuit to keep the temperature of the hot wire stable according to the output of the amplifying circuit, and a circuit for compensating for a phase of an output of the amplifying circuit contained in the feedback circuit.

Hot wire air flow meter

A high-speed scanning method uses a K(K.gtoreq.3)-number of semiconductor switch elements each having a first main electrode responsive to an input signal, a second main electrode, and a control electrode responsive to a control signal for controlling the transmissive and intransmissive states of said input signal from the first main electrode to the second main electrode; and capacitive loads connected respectively with the second main electrode of each of said K-number of semiconductor switch elements, for shifting one of the K-number of semiconductor switch elements sequentially with a predetermined period from the transmissive state to the intransmissive state or vice versa, wherein, the time, for which an arbitary L(K&gt;L.gtoreq.2)-number of semiconductor switch elements of adjacent scans are rendered transmissive, and the time, for which the L-number of semiconductor switch elements are rendered intransmissive, are included in at least one frame period, to elongate the period for which the scanning signals fluctuate, thereby permitting use of low-frequency semiconductor switches.

Method and circuit for scanning capacitive loads

In a drive processing circuit comprising a flow velocity measuring resistor and a temperature compensating resistor of a hot wire type air flow meter, a resistor is inserted between a connecting point of two resistors and an inverting input terminal of an operational amplifier. A condenser is inserted between an inverting input terminal of the amplifier and the non-inverting input terminal of the amplifier. A resistant value of the inserted resistor is set larger than a resistant value of the temperature compensating resistor. A low pass filter comprises the inserted resistor and the inserted condenser. The high frequency noises, which intrude through the temperature compensating resistor, are cut-off by the low pass filter.

Intake air flow rate measuring apparatus for use in internal combustion

Semiconductor components electrically connected in parallel are divided into a plurality of groups, with the control terminals of the semiconductor components constituting each group being connected in common to form a control terminal of the group, wherein the control terminals of the groups are mutually independent. A load current is limited by allowing specified ones of said semiconductor components to become conductive. Control of the load current is made possible without accompanying wasteful power dissipation.

Power semiconductor device including an arrangement for controlling load

A semiconductor electronic circuit, which can generate high voltage pulses, includes a current source coupled to form a series circuit with a pair of impedances between first and second voltage source terminals. A driving source is connected with a control terminal of the current source. Output voltage-current characteristics of the driving source are such that its output current is almost 0, when the output voltage is in the proximity of 0 V and that it is not 0 for other voltages. Thus, the voltage at the control terminal of the current source is clamped at a predetermined voltage level determined by the circuit structure of the driving source, when the voltage at the output terminal is lower than the predetermined voltage.

High voltage pulse generating semiconductor circuit with improved

A control method for an open channel for obtaining a stable condition of flow of water by coping with a transient change therein, comprising the steps of representing each space divided by gates of the open channel by a three water tank model including three imaginary water tanks in series and two imaginary conduits connecting the imaginary water tanks with each other; solving this model so as to obtain estimated future values of parameters of a state of the open channel; and determining a degree of opening of each gate so as to keep a liquid level of the space constant on the basis of the estimated future values of the parameters.

Control method for open channel

In semiconductor switches, erroneous firing is often a serious problem. To overcome this, a semiconductor switch is provided which includes a thyristor of PNPN structure with three PN junctions and with anode, cathode and gate electrodes, a first transistor for short-circuiting at least one PN junction of said thyristor upon its saturation, and a second transistor provided between the anode side or cathode side of the thyristor and the base of said first transistor to cause saturation of the first transistor in accordance with the voltage which is applied to the anode or cathode of the thyristor. The ratio of the time constant of the second transistor to that of said thyristor is not substantially less than 0.5. This ratio is established by using similar plane diffused patterns for the second transistor and a third transistor which is defined by three continuous layers of the thyristor.

Semiconductor switch

An ink-jet printing apparatus having a plurality of nozzles for projecting ink droplets which are selectively deposited on a printing medium in accordance with an information signal so as to form a printed pattern, such ink-jet printing apparatus comprising means for causing ink droplets used for printing to project from each nozzle in accordance with an information signal, a common power source for supplying a desired voltage to the ink-drop forming means provided at each nozzle thereby operating them, and switching means connected between the ink-drop forming means and the common power source and controlled by the information signal, the output of the power source being selectively supplied through the switching means to the ink-drop forming means, so that the driving system for driving the ink-drop forming means and the control system therefor can be separately provided, thus enabling a number of nozzles to be effectively controlled by a lowest control voltage.

Ink-jet printing apparatus

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Hitachioota, Japan

Masayoshi Suzuki