Semiconductor strain gauge bridge circuit

• US 4,911,016 A
• Filed: 02/13/1989
• Issued: 03/27/1990
• Est. Priority Date: 03/26/1986
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kobayashi, Ryoichi, Miyazaki, Atsushi
• Primary Examiner(s): Raevis, Robert R.
• Application Number:
  US07/310,018
• Time in Patent Office: 407 Days
• Field of Search: 338/3, 73/766, 73/708, 73/862.63, 73/720, 73/721, 73/726, 73/727, 323/366
• US Class Current: 73/766
• CPC Class Codes: G01L 1/2281 for temperature variations
• CPC Class Codes: G01L 19/0038 being part of the housing other details about the housing G01L19/14
• CPC Class Codes: G01L 19/148 Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
• 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 strain gauge bridge circuit device is disclosed to include a bridge circuit of semiconductor strain gauges, a first zero-point temperature compensation circuit connected to one of a pair of output terminals of the bridge circuit and including a voltage-dividing resistor circuit generating a voltage substantially equal to a potential appearing at the one output terminal at a predetermined temperature, and a second zero-point temperature compensation circuit connected to the other of the output terminals and including a resistive element having a temperature characteristic similar to that of the semiconductor strain gauges.

Claims

1. A semiconductor strain gauge bridge circuit device comprising:

a bridge circuit composed of semiconductor strain gauges and having a pair of power supply terminals to be connected to a power source and also having another pair of output terminals;

a first zero-point temperature compensation circuit connected across said power supply terminals and having a junction point connected through a resistor to one of said output terminals, said junction point being at a potential, when said power supply terminals are connected to a power source, which is substantially equal to a potential appearing at said one output terminal at a predetermined temperature; and

a nonlinearity compensation circuit connected across the other of said output terminals and one of said power supply terminals and having a non-linear temperature-resistance characteristic substantially the same as that of the semiconductor strain gauge bridge circuit so that a zero-point output versus temperature characteristic of the semiconductor strain gauge bridge circuit is substantially flattened over a predetermined temperature range that includes said predetermined temperature.

2. A semiconductor strain gauge bridge circuit device according to claim 1, wherein said nonlinearity compensation circuit includes a resistive element having a negative temperature-resistance characteristic and a fixed resistor connected in series with said resistive element.

3. A semiconductor strain gauge bridge circuit device according to claim 1, wherein said nonlinearity compensation circuit includes a resistive element having a negative temperature-resistance characteristic, a first fixed resistor connected in parallel with said resistive element, and a second fixed resistor connected in series with the parallel connection of said resistive element and said first fixed resistor.

4. A semiconductor strain gauge bridge circuit device according to claim 1, further comprising a sensitivity temperature compensation circuit through which the power source is connected to the other of said power supply terminals for compensating the temperature-dependent sensitivity of said bridge circuit.

5. A semiconductor strain gauge bridge circuit device according to claim 4, wherein said nonlinearity compensation circuit includes a resistive element having a negative temperature-resistance characteristic and a fixed resistor connected in series with said resistive element.

6. A semiconductor strain gauge bridge circuit device according to claim 4, wherein said nonlinearity compensation circuit includes a resistive element having a negative temperature-resistance characteristic, a first fixed resistor connected in parallel with said resistive element, and a second fixed resistor connected in series with the parallel connection of said resistive element and said first fixed resistor.