Method of regulating resistance value in sensor circuit

• US 6,768,320 B2
• Filed: 05/17/2002
• Issued: 07/27/2004
• Est. Priority Date: 05/21/2001
• Status: Expired due to Fees

• Current Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Original Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Inventors: Ono, Atsushi
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): Dole, Timothy J
• Application Number:
  US10/146,953
• Publication Number:
  US 20020171440A1
• Time in Patent Office: 802 Days
• Field of Search: 324/691, 324/686, 324/649, 324/658, 338/195
• US Class Current: 324/691
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: G01L 1/2262 involving simple electrical bridges

Abstract

In a pressure sensitive sensor circuit, a first conductive path has a first resistor which has a first resistance value and a second conductive path has a second resistor which has a second resistance value lower than the first resistance value of the first resistor and the second resistor is connected to the first resistor in series. A third conductive path has an open circuit which is connected to the second resistor in parallel. The open circuit of the third conductive path is short-circuited when a relationship between input pressure and output level in the pressure sensitive sensor circuit need to regulation of the resistance value in the pressure sensitive sensor.

Claims

1. A method of regulating a resistance value in a pressure sensitive sensor circuit, comprising the steps of:

providing a pressure sensitive sensor circuit including;

a first conductive path having a first resistor which has a first resistance value;

a second conductive path having a second resistor which has a second resistance value lower than the first resistance value of the first resistor, and the second resistor connected to the first resistor in series; and

a third conductive path having an open circuit which is connected to the second resistor in parallel, said third conductive path including a pair of lands separated from each other by a solder joinable distance, and the pair of lands connected to the second resistor in parallel;

inspecting a relationship between input pressure and output level in the pressure sensitive sensor circuit; and

short-circuiting the open circuit of the third conductive path based on the result of the inspection by depositing solder bridging said pair of lands.

2. A sensor circuit comprising:

a first resistor having a first resistance value;

a second resistor having a second resistance value lower than the first resistance value of the first resistor, and connected to the first resistor in series; and

an adjuster for regulating a resistance value in the sensor circuit, including a pair of lands separated from each other by a solder joinable distance, and the pair of lands connected to the second resistor in parallel, said second resistor being short-circuited when solder bridges said pair of lands.

3. The sensor circuit recited in claim 2, further comprising an electrostatic capacitance sensor connected to said second resistor, said electrostatic capacitance sensor being composed of a capacitor and a switch connected in series.

4. A sensor circuit comprising:

a first resistor having a first resistance value;

a second resistor having a second resistance value lower than the first resistance value of the first resistor, and connected to the first resistor in series; and

an adjuster for regulating a resistance value in the sensor circuit, including;

a first land, branched from upstream of the second resistor; and

a second land branched from downstream of the second resistor, and separated from the first land by a solder joinable distance, said second resistor being short-circuited when solder bridges said first and second lands.

5. The sensor circuit recited in claim 4, further comprising an electrostatic capacitance sensor connected to said second resistor, said electrostatic capacitance sensor being composed of a capacitor and a 0switch connected in series.

6. A sensor circuit comprising:

a first resistor having a first resistance value, said first resistor being comprised of a high resistance element having a relatively high resistance value and a low resistance element having a relatively low resistance value, and an adjuster for regulating a resistance value in the sensor circuit, including a pair of lands separated from each other by a solder joinable distance, and the pair of lands connected to the second resistor in parallel, said low resistance element being short-circuited when solder bridges said pair of lands; and

an electrostatic capacitance sensor connected to said first resistor, said electrostatic capacitance sensor being composed of a capacitor and a switch connected in series.

7. The sensor circuit recited in claim 6, further comprising:

a second resistor having a second resistance value, said second resistor being comprised of a high resistance element having a relatively high resistance value and a low resistance element having a relatively low resistance value, and an adjuster for regulating a resistance value in the sensor circuit, including a pair of lands separated from each other by a solder joinable distance, and the pair of lands connected to the second resistor in parallel, said low resistance element being short-circuited when solder bridges said pair of lands; and

a logic device connected to said first and second resistors and providing an output depending on an output of said electrostatic capacitance sensor.