Sensor driving device

Patent metadata

Field	Value
Publication number	US-10054502-B2
Application number	US-201615048014-A
Country	US
Kind code	B2
Filing date	Feb 19, 2016
Priority date	Mar 3, 2015
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

A sensor driving device drives a sensor circuit formed of a Wheatstone bridge, which is connected between a main power supply for supplying a power supply potential and a reference power supply for supplying a reference potential lower than the power supply potential and includes at least one gauge resistor varying a resistance value thereof with deformation caused by external force. The sensor driving device includes a first resistor, which is connected in series with the sensor circuit between the main power supply and the sensor circuit, and a second resistor, which is connected between the sensor circuit and the reference power supply. The sensor driving device further includes a temperature output circuit connected in parallel to the sensor circuit relative to the main power supply. The temperature output circuit includes two output terminals, which output a potential difference smaller than a potential difference between one end of a main power supply side and one end of a reference power supply side.

First claim

What is claimed is:

1. A sensor driving device for driving a sensor circuit formed of a Wheatstone bridge, which is connected between a main power supply for supplying a power supply potential and a reference power supply for supplying a reference potential lower than the power supply potential and includes at least one gauge resistor varying a resistance value thereof with deformation caused by external force, the sensor driving device comprising:
a first resistor connected in series with the sensor circuit between the main power supply and the sensor circuit;
a second resistor connected between the sensor circuit and the reference power supply; and
a temperature output circuit connected in parallel to the sensor circuit relative to the main power supply,
wherein the temperature output circuit includes two first output terminals, which output a potential difference smaller than a potential difference between one end of a main power supply side and one end of a reference power supply side.

2. The sensor driving device according to claim 1 , wherein:
the temperature output circuit includes a third resistor, a fourth resistor and a fifth resistor connected in this order between an intermediate node, which is between the first resistor and the sensor circuit, an intermediate node, which is between the sensor circuit and the second resistor; and
an intermediate node between the third resistor and the fourth resistor and an intermediate node between the fourth resistor and the fifth resistor form the first output terminals.

3. The sensor driving device according to claim 2 , wherein:
a combined resistance value of the third resistor, the fourth resistor and the fifth resistor is larger than each resistance value of the first resistor and the second resistor.

4. The sensor driving device according to claim 2 , wherein:
each resistance value of the first resistor and the second resist smaller than a resistance value of the sensor circuit.

5. The sensor driving device according to claim 2 , wherein:
each resistance value of the first resistor and the second resistor is smaller than a resistance value of the sensor circuit; and
a combined resistance value of the third resistor, the fourth resistor and the fifth resistor is larger than the resistance value of the sensor circuit.

6. The sensor driving device according to claim 1 , wherein:
the temperature output circuit includes a sixth resistor and a seventh resistor connected in this order between an intermediate node, which is between the first resistor and the sensor circuit, and the reference power supply;
the temperature output circuit further includes an eighth resistor and a ninth resistor connected in this order between the main power supply and an intermediate node between the sensor circuit and the second resistor; and
an intermediate node between the sixth resistor and the seventh resistor and an intermediate node between the eighth resistor and the ninth resistor form the first output terminals.

7. The sensor driving device according to claim 6 , wherein:
a resistance value of the seventh resistor is larger than a resistance value of the sixth resistor; and
a resistance value of the eighth resistor is larger than a resistance value of the ninth resistor.

8. The sensor driving device according to claim 6 , wherein:
the each resistance value of the first resistor and the second resistor is smaller than the resistance value of the sensor circuit.

9. The sensor driving device according to claim 6 , wherein:
the each resistance value of the first resistor and the second resistor is smaller than the resistance value of the sensor circuit;
a combined resistance value of the sixth resistor and the seventh resistor is larger than the resistance value of the sensor circuit; and
a combined resistance value of the eighth resistor and the ninth resistor is larger than the resistance value of the sensor circuit.

10. The sensor driving device according to claim 1 , wherein:
the first output terminals of the temperature output circuit and second output terminals of the sensor circuit are connected to an analog front end circuit through a multiplexer.

11. The sensor driving device according to claim 10 , wherein:
the first output terminals and the second output terminals are connected to the multiplexer through a switching circuit, which performs a chopping operation.

12. The sensor driving device according to claim 11 , wherein:
a signal amplifier circuit is provided between the switch circuit, which is connected to at least the second output terminals, and the multiplexer.

13. The sensor driving device according to claim 3 , wherein:
each resistance value of the first resistor and the second resistor is smaller than a resistance value of the sensor circuit.

14. The sensor driving device according to claim 3 , wherein:
each resistance value of the first resistor and the second resistor is smaller than a resistance value of the sensor circuit; and
a combined resistance value of the third resistor, the fourth resistor and the fifth resistor is larger than the resistance value of the sensor circuit.

15. The sensor driving device according to claim 4 , wherein:
each resistance value of the first resistor and the second resistor is smaller than a resistance value of the sensor circuit; and
a combined resistance value of the third resistor, the fourth resistor and the fifth resistor is larger than the resistance value of the sensor circuit.

16. The sensor driving device according to claim 7 , wherein:
the each resistance value of the first resistor and the second resistor is smaller than the resistance value of the sensor circuit.

17. The sensor driving device according to claim 7 , wherein:
the each resistance value of the first resistor and the second resistor is smaller than the resistance value of the sensor circuit;
a combined resistance value of the sixth resistor and the seventh resistor is larger than the resistance value of the sensor circuit; and
a combined resistance value of the eighth resistor and the ninth resistor is larger than the resistance value of the sensor circuit.

18. The sensor driving device according to claim 8 , wherein:
the each resistance value of the first resistor and the second resistor is smaller than the resistance value of the sensor circuit;
a combined resistance value of the sixth resistor and the seventh resistor is larger than the resistance value of the sensor circuit; and
a combined resistance value of the eighth resistor and the ninth resistor is larger than the resistance value of the sensor circuit.

Assignees

• Denso Corp

Inventors

• Nezuka Tomohiro

Classifications

• G01L9/045

  with electric temperature compensating means (non electric temperature compensating means G01L19/04) · CPC title

• G01L1/2262 Primary

  involving simple electrical bridges · CPC title

• G01K7/20

  in a specially-adapted circuit, e.g. bridge circuit · CPC title