Denso Corporation

Nippon Soken, Inc.

Nippondenso Co., Ltd.

Kazuyoshi Nagase

Shigeki Takahashi

Youichirou Suzuki

Noboru Maeda

Takahisa Koyasu

Koji Kondo

Yoshihiko Ozeki

Hironobu Baba

Takanori Makino

Shinji Ozaki

Tomohisa Kishigami

Hiroyuki Mori

Masahito Imai

Yukihiko Tanizawa

Yukihiro Kato

Takashi Nakano

Norio Sanma

Shigeki Otsuka

Hiroshi Nomura

Seiichirou Ootake

Makoto Hatanaka

Takasuke Ito

Seiichirou Otake

A signal output device is provided in a communication apparatus. The communication apparatus communicates with a different one of the communication apparatus using a single line. The signal output device includes a signal output unit. The signal output unit includes a first filter and a second filter. The first filter is provided by a Bessel filter. The second filter is provided by a Chebyshev filter or a Butterworth filter. The signal output unit outputs a signal which is obtained by passing a predetermined signal through the first filter and the second filter. The signal output from the signal output unit has a pass characteristic of the first filter and a pass characteristic of the second filter. A cutoff frequency of the first filter is set to be lower than a cutoff frequency of the second filter.

Signal output device

A receiving device includes a receiving circuit and an impedance control circuit. The receiving circuit receives a signal transmitted through a communication line. The impedance control circuit is coupled with the receiving circuit and has a detecting part. The detecting part detects a physical value of the signal and the physical value includes at least one of a voltage, an electric current, and an electric power. The impedance control circuit changes an input impedance based on the detected value so that a ringing of the signal is reduced.

Receiving device including impedance control circuit and semiconductor device including impedance control circuit

In a transmission device for differential communication, a first cathode-side element part is coupled between a first communication line and a cathode-side power supply line, a second cathode-side element part is coupled between a second communication line and the cathode-side power supply line, a first anode-side element part is coupled between the first communication line and an anode-side power supply line, and a second anode-side element part is coupled between the second communication line and the anode-side power supply line. A driving portion drives the element parts based on transmission data input from an outside. A target potential generating portion generates target potentials of the element parts based on potentials of the first communication line and the second communication line.

Transmission device for differential communication

A signal transmission circuit is capable of reducing distortion that occurs during signal transmission. A digital output signal is transmitted from a terminal to a signal line via an output buffer circuit and an output impedance unit. The terminal is connected to an impedance variation unit via an impedance control unit. The impedance variation unit designates an impedance for terminating the signal line when the output data is changed from a high level H to a low level. A reflection occurring on the signal line can be prevented and a waveform distortion can be suppressed.

Signal transmission circuit

A signal receiver includes: a receiving circuit that receives a differential signal via a transmission line, which includes a pair of signal wires for transmitting the differential signal; and an impedance control circuit that controls an input impedance so as to reduce a common mode noise. The impedance control circuit includes a detection element for detecting at least one of a voltage, a current and an electric power of the common mode noise. The impedance control circuit controls the input impedance in accordance with change of the at least one of the voltages the current and the electric power of the common mode noise.

Signal receiver for receiving differential signal via transmission line

A transmission apparatus for differential communication includes a driver bridge circuit and a pair of noise protection circuits. The driver bridge circuit includes four output devices that are independently connected between each of a pair of transmission lines and a power line or a ground line. Each noise protection circuit is provided to a corresponding transmission lines. Each noise protection circuit includes a ground potential detector and an impedance controller. The ground potential detector detects a potential of the corresponding transmission line with respect to the ground line. The impedance controller causes an impedance of the corresponding transmission line with respect to the ground line to become equal to an impedance of the other transmission line with respect to the ground line, when the detected potential becomes outside a predetermined potential range.

Transmission apparatus for differential communication

A bus switch for connecting and disconnecting a bus connection provided by a pair of buses includes a first switching element and a second switching element. The first switching element is coupled between an input terminal and an output terminal of a high-potential side bus of the pair of buses. The second switching element is coupled between an input terminal and an output terminal of a low-potential side bus of the pair of buses. The bus connection is connected when the first switching element and the second switching element are activated, and the bus connection is disconnected when the first switching element and the second switching element are deactivated.

Bus switch and electronic switch

An output circuit includes a constant current circuit that generates and supplies a constant current to an output terminal of the output circuit. Based on the constant current, the output circuit converts an input signal to an output signal having a voltage within a voltage range specified by upper and lower clamp voltages. The output signal is feedback to the constant current circuit. The constant current circuit changes the amount of the constant current in accordance with the output signal in such a manner that the constant current increases with an increase in the output signal and becomes zero when the output signal decreases to or below a threshold voltage. Thus, the upper clamp voltage is made as close to a power supply voltage as possible and the lower clamp voltage is made as close to a ground voltage as possible.

Output circuit and current source circuit used in the same

An analog switch used in a switched capacitor filter has N-channel and P-channel MOS FETs connected in parallel between input and output switch terminals, with capacitor charge currents being periodically produced from the output terminal. The filter derives an output signal with respect to a reference voltage and maintains the switch input and output terminal at the reference voltage, while respective substrate potentials of the N-channel and P-channel MOS FETs are fixed at the reference voltage, so that the analog switch does not produce an external flow of leakage current that can affect the output signal of the filter during each interval when the switch is open.

Analog switch having a minimized external flow of leakage current and switched capacitor filter incorporating the analog switch

When a voltage applied to an output terminal exceeds a power source voltage to be supplied during an ordinary operation state, a reset signal turns into L level and the operation mode of a sensor goes into a trimming operation mode. The voltage entered into the output terminal is changed in a voltage range higher that the power source voltage to input trimming data with a data signal having L or H level. The entered trimming data is temporarily held by a latch and then written into a memory in response to a write voltage applied to a power source terminal in a write mode. Then, the trimming data held by the latch or the trimming data stored in the memory can be read out as a change in the sink current of the output terminal when a read mode is set.

Physical quantity sensor with trimming function

In a disconnection detecting circuit comprising a control circuit and a sensor circuit, an energizing current is supplied from the control circuit side through an output terminal to the sensor circuit side by energizing a transistor in the sensor circuit side directly in a state where a pull-up resistor or a pull-down resistor having a several k&#x3a9; to several tens k&#x3a9; is provided in the control circuit side. In addition, a current control circuit, a constant-current circuit, a bias circuit and a transistor unit are provided in the sensor circuit side so that, at the occurrence of a disconnection of a power supply line, the impedance of the sensor circuit side is set to be higher by at least one-digit than the resistance value of the pull-up resistor in the control circuit side. This enables detecting a disconnection of connection lines between circuits while preventing an increase in contact resistance of terminal contacts to the utmost.

Disconnection detecting circuit for sensor apparatus

The full bridge circuit in a pressure sensor including semiconductor piezoelectric resistive elements in a pressure detection structure is connected to a filter. That is, first and second output terminals of the full bridge circuit is connected to a capacitor. One end of the capacitor is connected to the first output terminal through a first resistor. The other end of the capacitor is connected to the second output terminal through a second resistor. In an exhaust system of an engine, the pressure of the exhaust gas is detected to detect clogging in the black smoke removing unit. The filter removes the pulsate component in the detection signal derived from the pulsate component in the exhaust gas.

Semiconductor pressure sensor and an exhaust system including the same

A trimming circuit includes a signal separation circuit for separating an input signal into a clock signal, a reset signal, a data signal, and a memory writing voltage signal in accordance with voltage levels. The memory circuit in the trimming voltage control circuit has at least first and second different error correction circuits. The first error correction circuit has a higher error correction capability but lower input-per-output bit efficiency than the second error correction circuit to correct important data such as a highest bit inputted to a D/A converter. The second error correction circuit such as SEC has a higher input-per-output bit efficiency than the first error correction circuit to correct data with an error correction code. The lowest or second lowest input bits are directly supplied to the D/A converter without error correction.

Trimming circuit for a physical quantity sensor

A pressure detecting apparatus includes a sensing body with a diaphragm to which pressure is applied and a strain gauge plate having a {100} silicon substrate and a glass base, which is bonded on the sensing body. A thin portion and through holes are formed in the silicon substrate so that the thin portion has a beam structure on which strain gauges are formed. When the pressure is applied, the resistances of the strain gauges change in a positive direction, while the resistances of the strain gauges change in a negative direction. Accordingly, the linearity of the output from the pressure detecting apparatus can be improved.

Pressure detecting apparatus

A pressure detector comprises a pressure sensitive element composed of a semiconductor substrate having at least four gauge resistances and outputting signal in response to a pressure. A pressure transmission member is provided on the surface having the gauge resistors of the pressure sensitive element, for transmitting the pressure to the pressure sensitive element. Taking a crystal face of (110) as the face orientation of the pressure sensitive element, a bridge circuit is constructed by disposing a pair of gauge resistors in the direction of &lt;110&gt; of the crystal axis, disposing another pair of gauge resistors in the direction of &lt;100&gt; of the crystal axis and by connecting them each other. The bridge circuit is located within a pressurized surface which the pressure transmission member presses. Further, temperature compensating resistors are disposed in the direction of &lt;100&gt; of the crystal axis so as to be located also within the area of the pressurized surface.

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Kitanagoya, Japan

Kazuyoshi Nagase