Claims
- 1. A detecting circuit formed on a semiconductor substrate with a fixed potential point and a variable potential point having a potential difference from the fixed potential point that changes upon power-on, to detect that the potential difference between the fixed potential point and the variable potential point reaches a predetermined potential difference, comprising:a first resistor connected to the variable potential point; and a second resistor not connected to the variable potential point, and wherein said first resistor is formed in a first semiconductor region biased to a potential of the variable potential point, and said second resistor is formed in a second semiconductor region biased to a potential of the fixed potential point.
- 2. A circuit according to claim 1, wherein the fixed potential is a ground potential,said first resistor is a p-type diffusion resistor formed in an n-type semiconductor region, and said second resistor is an n-type diffusion resistor formed in a p-type semiconductor region.
- 3. A detecting circuit for detecting a power-on potential level, said detecting circuit being formed on a semiconductor substrate with a fixed potential point and a variable potential point having a potential difference from the fixed potential point that changes upon power-on, to detect that the potential difference between the fixed potential point and the variable potential point reaches the power-on potential level, comprising:a first resistor connected to the variable potential point; and a second resistor not connected to the variable potential point, and wherein said first resistor is formed in a first semiconductor region biased to a potential of the variable potential point, and said second resistor is formed in a second semiconductor region biased to a potential of the fixed potential point.
- 4. The circuit according to claim 3, wherein the fixed potential is a ground potential, said first resistor is a p-type diffusion resistor formed in a n-type semiconductor region, and said second resistor is an n-type diffusion resistor formed in a p-type semiconductor region.
- 5. The circuit according to claim 4, wherein the variable potential is a power supply potential.
- 6. The circuit according to claim 5, wherein the n-type semiconductor region is biased to the power supply potential, and the p-type semiconductor region is biased to the ground potential.
- 7. The circuit according to claim 3, further comprising:a low pass filter coupled between the variable potential point and a power supply terminal.
- 8. The circuit according to claim 7, wherein the fixed potential is a ground potential, said first resistor is a p-type diffusion resistor formed in an n-type semiconductor region, and said second resistor is an n-type diffusion resistor formed in a p-type semiconductor region.
- 9. The circuit according to claim 8, wherein the variable potential is a power supply potential.
- 10. The circuit according to claim 9, wherein the n-type semiconductor region is biased t the power supply potential, and the p-type semiconductor region is biased to the ground potential.
Priority Claims (2)
Number |
Date |
Country |
Kind |
9-042228 |
Feb 1997 |
JP |
|
9-044245 |
Feb 1997 |
JP |
|
Parent Case Info
This application is a divisional of prior application Ser. No. 09/030,915 filed Feb. 26, 1998, now U.S. Pat. No. 6,052,313.
US Referenced Citations (6)
Foreign Referenced Citations (3)
Number |
Date |
Country |
0 476 282 A2 |
Mar 1992 |
EP |
2-116084 |
Apr 1990 |
JP |
6-243677 |
Sep 1994 |
JP |