Sensor IC

• US 5,640,090 A
• Filed: 12/28/1995
• Issued: 06/17/1997
• Est. Priority Date: 01/31/1995
• Status: Expired due to Term

• Current Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Original Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Inventors: Watanabe, Atsushi, Urushiyama, Hirohiko, Yano, Katsuaki, Furuya, Misao
• Primary Examiner(s): O'Shea, Sandra L.
• Assistant Examiner(s): PHILLIPS, ROGER
• Application Number:
  US08/580,379
• Time in Patent Office: 537 Days
• Field of Search: 324/207.2, 324/207.12, 324/225, 324/251, 338/32 H, 327/511, 327/510, 73/862.381, 73/862.473, 73/862.581, 73/862.391
• US Class Current: 324/251
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01L 1/225 Measuring circuits therefor
• CPC Class Codes: G01R 33/07 Hall effect devices

Abstract

A sensor IC generates a voltage according to magnetic flux density of an applied magnetic field. The sensor IC includes a plurality of Hall sensors having an identical shape formed adjacent to each other in a semiconductor chip, each of the Hall sensors generating a sensor output voltage which includes a Hall output voltage component in proportion to the magnetic flux density. The sensor IC further includes a plurality of differential amplifiers having an identical circuit formed adjacent to each other in the semiconductor chip, each of the differential amplifiers multiplying the sensor output voltage produced from a corresponding one of the Hall sensors by a given gain. In the sensor IC, by a summing circuit, output signals produced from the plurality of differential amplifiers are summed.

Claims

1. A sensor IC generating a voltage according to magnetic flux density of an applied magnetic field, said sensor IC comprising:

a plurality of Hall sensors having an identical shape formed adjacent to each other in a semiconductor chip, each of the Hall sensors generating a sensor output voltage which includes a Hall output voltage component in proportion to said magnetic flux density;

a plurality of differential amplifiers having an identical pattern and an identical circuit formed adjacent to each other in said semiconductor chip, each of the differential amplifiers multiplying said sensor output voltage produced from a corresponding one of the Hall sensors by a given gain; and

a summing circuit summing output signals produced from said plurality of differential amplifiers, said summing circuit having at least two load resisters having an identical shape and an identical value formed adjacent to each other in said semiconductor chip, each of said load resisters being connected to said plurality of differential amplifiers in common so as to provide summing of output current of the plurality of differential amplifiers.

2. The sensor IC as claimed in claim 1, wherein said sensor IC further comprises a waveform-shaping circuit comparing an output voltage of said summing circuit with a reference voltage and converting said output signal of the summing circuit to a digital signal having two levels.

3. A sensor IC generating a voltage according to applied pressure, said sensor IC comprising:

a plurality of semiconductor pressure sensors having an identical shape formed adjacent to each other in a semiconductor chip, each of the sensors generating a sensor output voltage which includes a detected voltage component in proportion to said applied pressure;

a plurality of differential amplifiers having an identical pattern and an identical circuit formed adjacent to each other in said semiconductor chip, each of the differential amplifiers multiplying said sensor output voltage produced from a corresponding one of the semiconductor pressure sensors by a given gain; and

a summing circuit summing output signals produced from said plurality of differential amplifiers, said summing circuit having at least two load resistors having an identical shape and an identical value formed adjacent to each other in said semiconductor chip, each of said load resistors being connected to said plurality of differential amplifiers in common so as to provide summing of output current of the plurality of differential amplifiers.