JPS57172595A - Memory protecting circuit - Google Patents
Memory protecting circuitInfo
- Publication number
- JPS57172595A JPS57172595A JP56056628A JP5662881A JPS57172595A JP S57172595 A JPS57172595 A JP S57172595A JP 56056628 A JP56056628 A JP 56056628A JP 5662881 A JP5662881 A JP 5662881A JP S57172595 A JPS57172595 A JP S57172595A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- memory
- reference value
- power supply
- power voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
PURPOSE: To enable with a simple circuit to prevent memory contents from being destroyed when turn on an electric power supply or the power supply is turned off, by making the selection line of a memory circuit unselected when a power voltage is lower than a reference value.
CONSTITUTION: A power-on resetting circuit A which generates a reset signal when a power supply is turned on and has a time constant depending upon a resistance R3 and a capacitor C1 is provided and the memory protecting circuit of a memory circuit 2 which is powered down by a battery BA is provided with a detecting circuit which detects a power voltage Vcc exceeding a prescribed reference value. Then when the power voltage Vcc is lower than the reference value, the capacitor C1 is discharged and at the same time, the selection line of the memory circuit 2 is made unselected. For example, a circuit which includes a microcomputer 1, a Zener diode ZD, etc., as shown in the figure is used to perform said operation.
COPYRIGHT: (C)1982,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP56056628A JPS57172595A (en) | 1981-04-15 | 1981-04-15 | Memory protecting circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP56056628A JPS57172595A (en) | 1981-04-15 | 1981-04-15 | Memory protecting circuit |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS57172595A true JPS57172595A (en) | 1982-10-23 |
Family
ID=13032561
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP56056628A Pending JPS57172595A (en) | 1981-04-15 | 1981-04-15 | Memory protecting circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS57172595A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59202526A (en) * | 1983-04-30 | 1984-11-16 | Minolta Camera Co Ltd | Voltage drop protecting circuit of control circuit |
JPH0314150A (en) * | 1989-06-13 | 1991-01-22 | Hitachi Maxell Ltd | Memory card |
KR100231139B1 (en) * | 1996-08-28 | 1999-11-15 | 문정환 | Reset signal generating circuit |
JP2008075795A (en) * | 2006-09-22 | 2008-04-03 | Japan Aviation Electronics Industry Ltd | Sucker sheet |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS52116027A (en) * | 1976-03-25 | 1977-09-29 | Casio Comput Co Ltd | Memory protection circuit in small size electronic devices |
JPS5531133B2 (en) * | 1976-08-04 | 1980-08-15 | ||
JPS5627734B2 (en) * | 1973-02-22 | 1981-06-26 |
-
1981
- 1981-04-15 JP JP56056628A patent/JPS57172595A/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5627734B2 (en) * | 1973-02-22 | 1981-06-26 | ||
JPS52116027A (en) * | 1976-03-25 | 1977-09-29 | Casio Comput Co Ltd | Memory protection circuit in small size electronic devices |
JPS5531133B2 (en) * | 1976-08-04 | 1980-08-15 |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59202526A (en) * | 1983-04-30 | 1984-11-16 | Minolta Camera Co Ltd | Voltage drop protecting circuit of control circuit |
JPH0314150A (en) * | 1989-06-13 | 1991-01-22 | Hitachi Maxell Ltd | Memory card |
KR100231139B1 (en) * | 1996-08-28 | 1999-11-15 | 문정환 | Reset signal generating circuit |
JP2008075795A (en) * | 2006-09-22 | 2008-04-03 | Japan Aviation Electronics Industry Ltd | Sucker sheet |
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