Seiko Instruments Inc

Gakkouhoujin Chikoujigakuen

Ryoichi Anzai

Minoru Ariyama

Atsushi Igarashi

Hirokazu Yoshizawa

Toshiyuki Uchida

Akira Takeda

Provided is a two-terminal semiconductor sensor device with which an external device having low circuit or element accuracy may be used. An output voltage (VOUT) of the two-terminal semiconductor sensor device based on temperature is not based on a constant current of a constant current source () of the external device and a current of an output transistor () of the two-terminal semiconductor sensor device, but on a resistance ratio of a voltage dividing circuit including a resistor () and a resistor (), and a temperature voltage (Vbe) of the two-terminal semiconductor sensor device. Accordingly, accuracy of the constant current of the constant current source () of the external device that receives the output voltage (VOUT) does not need to be high. Therefore, the external device does not need to have a highly accurate circuit or element for receiving the output voltage (VOUT).

Two-terminal semiconductor sensor device

To provide a PDM output temperature sensor, which is reduced in area and consumption power, provided is a PDM output temperature sensor which includes no reference voltage circuit, thereby having a smaller area and consuming less power correspondingly.

PDM output temperature sensor

Provided is a temperature compensating circuit, which conducts a temperature correction having a continuous characteristic, and is small in the circuit scale. An output voltage VOUT at a connection pointis determined on the basis of a current Ia, a current Ib, and a current Ic, and an output voltage of a temperature sensor circuit is corrected by the output voltage VOUT with a temperature. As a result, the temperature correction having the continuous characteristic is conducted on the basis of a current change of the current Ia, the current Ib, and the current Ic. Because the plural temperature compensating circuits are not provided, and only one temperature compensating circuit is provided, the circuit scale becomes smaller.

Temperature compensating circuit

Provided is a chopper amplifier circuit capable of eliminating an influence of a slew rate of an amplifier and suppressing spike generation to thereby obtain an output signal having little harmonic distortion. The chopper amplifier circuit according to the present invention includes: a first chopper circuit for chopping an input signal by a first pulse and a second pulse shifted from each other in phase by a half cycle, switching a relation of connection between an input terminal pair and an output terminal pair at a timing of the chopping, and outputting the input signal as a modulated signal; an amplifier for amplifying the modulated signal and outputting the modulated signal thus amplified as an amplified signal; a first sample hold circuit for holding the amplified signal at the first pulse and outputting the amplified signal at the second pulse; and a second sample hold circuit for holding the amplified signal at the second pulse and outputting the amplified signal at the first pulse.

Amplifier circuit

Provided is a chopper amplifier circuit capable of reducing an offset voltage of a sensor bridge and temperature characteristics of the offset voltage. An offset adjusting voltage generation circuit for generating a voltage equal to an offset voltage of a sensor bridge and an offset temperature characteristics adjusting voltage generation circuit for generating a voltage having temperature characteristics equal to those of the offset voltage are provided. These output voltages are chopper-modulated and subtracted from a chopper-modulated output signal of the sensor bridge.

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Chiba, Japan

Ryoichi Anzai