Denso Corporation

Nippondenso Co., Ltd.

Jeco Co., Ltd.

Yukihiko Tanizawa

Yasutoshi Suzuki

Tsuyoshi Fukada

Hiroaki Tanaka

Inao Toyoda

Hiroshi Okada

Kazuhisa Ikeda

Minekazu Sakai

Seiichiro Ishio

Masahito Imai

Hiroshi Tanaka

Yoshimi Yoshino

Kazuyoshi Nagase

Yoshifumi Murakami

Motoki Ito

Hironobu Baba

Nobukazu Oba

Takashige Saitou

Kazuaki Hamamoto

Masahiro Aratani

Masato Ishihara

Seiichirou Ootake

Yoshitsugu Abe

Koki Mizuno

Norio Miyahara

Takeshi Tukamoto

An A/D conversion circuit includes: first/second pulse circulation circuits delaying an input signal and circulating a pulse signal; a circulation number difference measurement section outputting a difference between circulation time numbers of the pulse signal through the first/second pulse circulation circuits; a conversion control circuit outputting the difference as A/D conversion data when outputting a conversion data output processing signal; and a signal ratio change circuit: outputting, from a first output terminal, a voltage calculated by adding the reference voltage and a voltage obtained by multiplying a differential voltage, obtained by subtracting the reference voltage from the analog input voltage, by a first proportional coefficient; and outputting, from a second output terminal, a voltage calculated by subtracting, from the reference voltage, a voltage obtained by multiplying the differential voltage by a second proportional coefficient. The first/second pulse circulation circuits receive power source voltage supply from the first/second output terminals and a ground line.

Analog/digital conversion circuit

In a sensor signal processing apparatus, a control unit executes at least one of a temperature measurement process and a calculation process in parallel with a signal conversion process. In the temperature measurement process, the control unit causes a second A/D converter to execute the A/D conversion of a temperature signal. In the calculation process, the control unit calculates an offset and a conversion gain of a first A/D converter base on an A/D conversion value output from the second A/D converter and pre-prepared temperature characteristic data of a physical quantity sensor. In the signal conversion process, the control unit sets the calculated offset and the calculated conversion gain to the first A/D converter, and causes the first A/D converter to execute the A/D conversion of the sensor signal.

Sensor signal processing apparatus and sensor apparatus

An A/D converter circuit includes first to fourth pulse circulation circuits and first and second counters and configured to provide high conversion accuracy irrespective of a temperature change. The first pulse circulation circuit operates with a difference voltage of a specified voltage and an analog input voltage. The first counter outputs a difference of the number of pulse circulation in the first and the second pulse circulation circuits. The third pulse circulation circuit operates with a difference voltage of the specified voltage and a set voltage. The fourth pulse circulation circuit operates with the set voltage. The second counter outputs a difference of the number of pulse circulation in the third and the fourth pulse circulation circuits. When an output value of the second counter reaches a specified value, an output value of the first counter at that time is outputted as A/D conversion data.

A/D converter circuit including pulse circulation circuit with delay units coupled together in ring shape

A sensor circuit includes an analog-to-digital converter, a control circuit, a calculation circuit, and a pulse width modulation converter. The analog-to-digital converter converts an electric signal associated with a detected physical quantity to sensor data by sampling the electric signal a predetermined sampling number times per a predetermined sampling section. The control circuit determines the sampling number based on a magnitude of the electric signal. The calculation circuit calculates an average value of all the sensor data per the sampling section. The pulse width modulation converter generates a pulse width modulation signal having a pulse width corresponding to the average value.

Pulse width modulation output type sensor circuit for outputting a pulse having a width associated with a physical quantity

A differential amplification circuit and a method corrects an offset voltage derived from a variance in resistances. With first and second input terminals brought to the same potential and set to a potential different from a reference potential, the resistance value of resistors is adjusted so that an output potential and the reference potential will be substantially equal to each other.

Differential amplification circuit and manufacturing method thereof

A mounting structure for a current sensor is provided. The current sensor is arranged between a negative terminal of a battery and a grounding unit. The mounting structure includes a battery grounding cable which has one end connected with the negative terminal of the battery, and a fixing unit which is electrically conductive to electrically connect other end of the battery grounding cable with the grounding unit. The fixing unit and the battery grounding cable constructs a current path which connects the negative terminal with the grounding unit. The current sensor is fixed by the fixing unit to the grounding unit, and disposed to detect current flowing through the fixing unit.

Mounting structure for current sensor

An A/D converter circuit has a first ring delay line and a second ring delay line configured to vary respective characteristics in the same manner relative to a change in the ambient temperature. A reference voltage, which is free from a change in temperature, is fed as a power supply voltage to the second ring delay line. Digital data produced by the first ring delay line is temperature-compensated by digital data produced by the second ring delay line.

A/D converter circuit and A/D conversion method

An A/D converter circuit uses first and second ring delay lines. The first and second ring delay lines are supplied with input signals, which increase/decrease oppositely from each other with respect to change directions. In each ring delay line, a first counter counts the number of times of circulation of a pulse signal circulating therein to find a digital data, and a last digital data is subtracted from a present digital data. By adding the resulting first and second digital data of the first and second ring delay lines, a digital data of the input voltage of linear characteristics is provided.

A current measuring device for detecting current flowing in a current path includes a magnetic sensor for detecting a magnetic field and a magnetic sensor for detecting earth magnetism, the magnetic field detecting magnetic sensor and the earth magnetism detecting magnetic sensor being disposed along the direction of magnetic flux induced by the current flowing in the current path, wherein an earth magnetism component detected by the magnetic field detecting magnetic sensor is canceled by using earth magnetism detected by the earth magnetism detecting magnetic sensor.

Current measuring device

A current detection apparatus includes a magnetic core having a ring shape with a gap and a center opening portion through which a current path is disposed, and a magnetic sensor including a magnetic sensing element such as a Hall effect element arranged in the gap. When a current flows through the current path, the magnetic core generates magnetic flux therein so that magnetic field is generated in the gap. The magnetic sensor outputs different electrical signals, each of which is measured in a different measurement range and corresponds to intensity of the magnetic field in the gap. The current detection apparatus measures the current based on the electrical signals outputted from the magnetic sensor.

Current detection apparatus

A physical quantity is detected by approximating a relationship between an output of a sensor and the physical quantity to be determined by the sensor by setting as coefficients of a quadratic equation a temperature characteristic of non-linearity of the sensor to the physical quantity and temperature characteristics of parameters affecting the output of the sensor. Each of the coefficients is approximated by a higher-order equation with the temperature set as an independent variable, and the temperature coefficient is stored in advance. The temperature coefficient stored in the storage unit and the real-time temperature are substituted into the higher-order equation. The achieved coefficients and the output of the sensor are substituted into the quadratic equation to calculate the actual physical quantity.

Physical quantity detecting method and sensor device

A constant current circuit in which a bias voltage of a field effect transistor is set includes a bias circuit which sets, as the bias voltage, a gate-source voltage V' corresponding to an intersecting point between an I- Vcharacteristic curve at arbitrary first temperature and an I-Vcharacteristic curve at arbitrary second temperature which is different from the first temperature in the I-Vcharacteristic of the drain current Ito a gate-source voltage Vof the field effect transistor. The bias circuit is comprised of a plurality of semiconductor resistors having substantially similar temperature coefficients so as to be able to transmit heat to each other.

Constant current circuit

Predetermined reference voltages v, vare A/D-converted to achieve corresponding digital data d, d, d. Any reference digital values y, yare set in advance so as to satisfy y/y=(v&#x2212;v)/(v&#x2212;v)=&#xbd;. Furthermore, calculations of x=d&#x2212;dand x=d&#x2212;dare carried out to achieve x, x. A quadratic curve (quadratic function expression y=f(x)) passing a point D (x, y) and a point E (x, y) and the origin on the xy coordinate system is set as a linearly correcting expression. A shift value x achieved by subtracting dfrom data ds having non-linearity from the A/D converting circuit is corrected by the linearly correcting expression thus achieved to achieve a linearly corrected value y to ds.

Non-linearity correcting method and device for A/D conversion output data

First and second resistors (sensing elements) are connected in series between first and second potentials. The junction point voltage between the first and second resistor is supplied to an inverting input of a first operational amplifier. The non-inverting input is supplied with a reference voltage Vref generated by third and fourth resistors. A feedback resistor is connected between output and inverting input of the operational amplifier OP . The difference between a temperature coefficient of resistance TCR of the sensing elements and a temperature coefficient of sensitivity TCS is equalized to a temperature coefficient of resistance of the feedback resistor. Further, the reference voltage is unchanged in accordance with the detected physical quantity or temperature variation.

Physical quantity detection device with temperature compensation

A pressure sensor is supplied with a supply voltage from a system control circuit having the function for changing the supply voltage. When the supply voltage is within a predetermined voltage range, the pressure sensor outputs the detection signal corresponding to the pressure to be measured and outputs a predetermined voltage which is irrespective of the pressure. More specifically, the system control circuit outputs the supply voltage at a value outside a predetermined voltage range in a diagnostic mode, that is, a value which is higher than the measuring mode, in order to turn on the transistors Q and Q to supply the predetermined voltage to the system control circuit to detect an error caused by increase in contact resistance between the pressure sensor and the system control circuit.

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Kariya, Japan

Yukihiko Tanizawa