Semiconductor pressure detection device

• US 4,300,395 A
• Filed: 10/25/1979
• Issued: 11/17/1981
• Est. Priority Date: 11/08/1978
• Status: Expired due to Term

• Current Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
• Original Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
• Inventors: Shirouzu, Shunji, Noda, Ryuzo
• Primary Examiner(s): Woodiel, Donald O.
• Application Number:
  US06/087,938
• Time in Patent Office: 754 Days
• Field of Search: 73/708, 73/720, 73/721, 73/726, 73/727, 73/766, 338/4, 338/7, 338/8, 338/42, 357/26
• US Class Current: 73/708
• CPC Class Codes: G01K 7/01 using semiconducting elements having PN junctions G01K7/02, G01K7/16, G01K7/30 take precedence
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm
• CPC Class Codes: G01L 9/065 with temperature compensating means non electric temperature compensating means G01L19/04

Abstract

A semiconductor pressure detection device is provided which is adapted to detect pressure using resistors formed in the surface area of a semiconductor substrate and having a piezo-effect. A diode is formed in the surface area of the semiconductor substrate and a drive voltage corresponding to a temperature variation is supplied to a bridge circuit through the diode.

Claims

1. A semiconductor pressure detection device comprising:

a semiconductor substrate of a first conductivity type;

a first semiconductor region of a second conductivity type formed in the surface area of said semiconductor substrate to provide, together with said semiconductor substrate, a temperature-sensitive diode;

power supply means connected to said diode to generate a voltage according to a variation of a forward voltage of said diode resulting from a temperature variation; and

a bridge circuit including a resistive semiconductor region of said second conductivity type which is formed in the surface area of said semiconductor substrate and has a piezo-effect, said bridge circuit being adapted to receive an output voltage of said power supply means and produce output voltage according to pressure applied;

wherein said semiconductor substrate is made of an N-type semiconductor and attached to a base having a pressure introduction hole, the semiconductor region of said second conductivity type is made of a P-type semiconductor, and said power supply means comprises a first reference power supply for supplying a reference voltage to a diode, an amplifier connected to said diode and a second reference power supply for controlling an output voltage by a transistor which is controlled by an output of said amplifier.

4. A semiconductor pressure detection device according to claim 1 or claim 3 in which said bridge circuit comprises a first bridge portion including two resistive semiconductor regions each showing a mutually opposite-polarity piezo-effect and a first voltage dividing resistor connected between said two resistive semiconductor regions and having no piezo-effect and a second bridge portion including a second voltage dividing resistor having no piezo-effect, in which an output voltage is detected between the first and second voltage dividing points.

5. A semiconductor pressure detection device according to claim 1 or claim 3 in which said bridge circuit comprises a first bridge portion including two resistive semiconductor regions each showing a mutually opposite-polarity piezo-effect and a first voltage dividing resistor connected between said two resistive semiconductor regions and having no piezo-effect, a second bridge portion including two resistive semiconductor regions each having a mutually opposite-polarity piezo-effect and a second voltage dividing resistor connected between said two resistive semiconductor region and having no piezo-effect, said first and second bridge circuit portions being combined such that the adjacent elements each have an opposite-polarity piezo-effect, and first and second variable resistors connected to voltage dividing points of said first and second voltage resistors, respectively, in which an output voltage is detected between the first variable resistor and the second variable resistor.

2. A semiconductor pressure detection device comprising:

a first reference voltage terminal adapted to receive a first reference voltage;

a second reference voltage terminal adapted to receive a second reference voltage different from the first reference voltage;

a semiconductor substrate of a first conductivity type;

a semiconductor region of a second conductivity type formed in the surface area of the semiconductor substrate connected to the first reference voltage terminal and biased in forward direction and constituting a temperature-sensitive diode together with the semiconductor substrate;

a bridge circuit having resistive semiconductor regions of the second conductivity type formed in the surface area of the semiconductor substrate connected to the second reference voltage terminal and biased in reverse direction and possessing piezo-effect; and

a transistor connected to the semiconductor region, the resistive semiconductor regions and the second reference voltage terminal and adapted to apply the second reference voltage to the resistive semiconductor region in accordance with the terminal voltage of said diode.

3. A semiconductor pressure detection device according to claim 2, in which said semiconductor substrate is of N type and connected to ground, said resistive semiconductor regions are of P type, and said first and second reference voltage terminals are connected respectively to a positive voltage source and a negative voltage source.

6. A temperature compensation method for a semiconductor pressure detection device comprising a bridge circuit which is formed of a first bridge portion including two resistors each having matually opposite-polarity piezo-effect and a first voltage dividing resistor connected between the two resistors and having no piezo-effect and a second bridge portion including a second voltage dividing resistor having no piezo-effect in which an output voltage is detected between a voltage dividing point of the first voltage dividing resistor and a voltage dividing point of the second voltage dividing resistor, comprising the steps of:

dividing said second voltage dividing resistor to obtain a voltage dividing ratio of 1/2 and setting the voltage dividing ratio of said first voltage dividing resistor whereby the temperature characteristic of an output voltage between both the voltage dividing points when no pressure is applied such that it is becomes similar to the temperature characteristic of an output voltage of power supply means; and

setting the voltage dividing ratio of said second voltage dividing resistor such that the temperature characteristic of a potential on the voltage dividing point of said second voltage dividing resistor is made equal to the temperature characteristic of a potential on the voltage dividing point of said first voltage dividing resistor.

7. A temperature compensation method for a semiconductor pressure detection device comprising a bridge circuit which is formed of a first bridge portion including two resistors each having no mutually opposite-polarity piezo-effect and a first voltage dividing resistor connected between said two resistors and having no piezo-effect and a second bridge portion including a second voltage dividing resistor having no piezo-effect in which an output voltage is detected between the voltage dividing points of said first and second voltage dividing resistors, comprising the steps of:

setting the voltage dividing ratio of said first voltage dividing resistor such that the temperature characteristic of a potential on the first voltage dividing point when no pressure is applied is linearized; and

setting the voltage dividing ratio of said second voltage dividing resistor such that the temperature characteristic of a potential on the voltage dividing point of the second voltage dividing resistor when no pressure is applied is made equal to the temperature characteristic of a potential on the first voltage dividing point.

8. A temperature compensation method for a semiconductor pressure detection device comprising a bridge circuit which is formed of a first bridge portion including two resistors each having a mutually opposite-polarity piezo-effect and a first voltage dividing resistor connected between the two resistors and having no piezo-effect and a second bridge portion including two resistors each having a mutually opposite-polarity piezo-effect and a second voltage dividing resistor connected between the two resistors and having no piezo-effect, said first and second bridge portions being combined such that the adjacent resistors each have a mutually opposite piezo-effect, and first and second variable resistors connected to the voltage dividing points of said first and second voltage dividing resistors in which an output voltage is detected between the first and second variable resistors, comprising the steps of:

setting the voltage dividing ratio of the first and second voltage dividing resistors such that the temperature characteristic of an output voltage between both the voltage dividing points of said first and second voltage dividing resistors when no pressure is applied becomes similar to the temperature characteristic of an output voltage of power supply means;

causing a value of one variable resistor connected to one of the first and second voltage dividing resistors to become zero, the amount of variation of a potential on the voltage dividing point of said one voltage dividing resistor being smaller than that on the voltage dividing point of the other voltage dividing resistor; and

setting a value of the other variable resistor such that the amount of variation of a potential on the output terminal of said other variable resistor resulting from a temperature variation is made equal to an amount of variation of a potential on the output terminal of said one variable resistor resulting from the temperature variation.