JPS6436391A - Ic memory card - Google Patents

Ic memory card

Info

Publication number
JPS6436391A
JPS6436391A JP62192842A JP19284287A JPS6436391A JP S6436391 A JPS6436391 A JP S6436391A JP 62192842 A JP62192842 A JP 62192842A JP 19284287 A JP19284287 A JP 19284287A JP S6436391 A JPS6436391 A JP S6436391A
Authority
JP
Japan
Prior art keywords
write enable
terminal
inverse
semiconductor memory
memory card
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.)
Granted
Application number
JP62192842A
Other languages
Japanese (ja)
Other versions
JP2578819B2 (en
Inventor
Koji Sanada
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to JP62192842A priority Critical patent/JP2578819B2/en
Publication of JPS6436391A publication Critical patent/JPS6436391A/en
Application granted granted Critical
Publication of JP2578819B2 publication Critical patent/JP2578819B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Landscapes

  • Credit Cards Or The Like (AREA)
  • Static Random-Access Memory (AREA)
  • Techniques For Improving Reliability Of Storages (AREA)

Abstract

PURPOSE:To prevent error writing when an IC memory card is sampled from a system by providing a reverse-current prevention element between the write enable input terminals of the IC memory card and a semiconductor memory and inserting a resistor between the write enable input terminal of the semiconductor card and the power terminal of the semiconductor memory. CONSTITUTION:In the same manner to an external power source VCC, the write enable terminal, the inverse of WE is connected to the write enable terminal, the inverse of WE' of the semiconductor memory RAM1-m through a PNP type bipolar transistor Q4 and the write enable terminal, the inverse of WE' is connected to the power source VCC' through the resistor R6. Therefore, even when the external power source VCC and a write enable signal are turned off to zero volt at the same time, the write enable signal is interrupted by the PNP type bipolar transistor Q4, the voltage three volt of an internal battery BAT is supplied to the write enable terminal, the inverse of WE' of the semiconductor memory RAM1-m through the resistor R6. Thus the write enable signal is not turned to zero volt and the error writing can be prevented. Besides, the error writing can be prevented even when the utilized IC memory card is sampled from the system by mistake.
JP62192842A 1987-07-31 1987-07-31 IC memory card Expired - Lifetime JP2578819B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62192842A JP2578819B2 (en) 1987-07-31 1987-07-31 IC memory card

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62192842A JP2578819B2 (en) 1987-07-31 1987-07-31 IC memory card

Publications (2)

Publication Number Publication Date
JPS6436391A true JPS6436391A (en) 1989-02-07
JP2578819B2 JP2578819B2 (en) 1997-02-05

Family

ID=16297887

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62192842A Expired - Lifetime JP2578819B2 (en) 1987-07-31 1987-07-31 IC memory card

Country Status (1)

Country Link
JP (1) JP2578819B2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0344721A (en) * 1989-07-12 1991-02-26 Toshiba Corp Detecting circuit for memory back-up voltage
JPH04112209A (en) * 1990-09-03 1992-04-14 Fuji Electric Co Ltd Programmable controller

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5990279A (en) * 1982-11-12 1984-05-24 Toshiba Corp Interface circuit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5990279A (en) * 1982-11-12 1984-05-24 Toshiba Corp Interface circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0344721A (en) * 1989-07-12 1991-02-26 Toshiba Corp Detecting circuit for memory back-up voltage
JPH04112209A (en) * 1990-09-03 1992-04-14 Fuji Electric Co Ltd Programmable controller

Also Published As

Publication number Publication date
JP2578819B2 (en) 1997-02-05

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