JPH06231598A - Prom circuit - Google Patents

Prom circuit

Info

Publication number
JPH06231598A
JPH06231598A JP1602493A JP1602493A JPH06231598A JP H06231598 A JPH06231598 A JP H06231598A JP 1602493 A JP1602493 A JP 1602493A JP 1602493 A JP1602493 A JP 1602493A JP H06231598 A JPH06231598 A JP H06231598A
Authority
JP
Japan
Prior art keywords
redundant
circuit
signal
write
fuse
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
Application number
JP1602493A
Other languages
Japanese (ja)
Inventor
Hiroshi Takahashi
浩 高橋
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 IC Microcomputer Systems Co Ltd
Original Assignee
NEC IC Microcomputer Systems Co Ltd
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 IC Microcomputer Systems Co Ltd filed Critical NEC IC Microcomputer Systems Co Ltd
Priority to JP1602493A priority Critical patent/JPH06231598A/en
Publication of JPH06231598A publication Critical patent/JPH06231598A/en
Pending legal-status Critical Current

Links

Landscapes

  • For Increasing The Reliability Of Semiconductor Memories (AREA)
  • Read Only Memory (AREA)

Abstract

PURPOSE:To prevent the change of the changeover address signal of a stored redundant memory due to the erroneous application of high voltage to a specific terminal by a user in a PROM circuit. CONSTITUTION:An AND circuit 3, to which a control signal 102 output at a time when a control fuse cell 2 is brought to an unwritten state and a redundant-circuit active signal 103 are input and from which a write permit signal 104 activating a redundant fuse-cell write circuit 4 is output, is installed. Accordingly, the redundant fuse-cell write circuit 4 is not activated even when the redundant-circuit active signal 103 is selected by conducting write to the control fuse cell 2, thus preventing the change of a redundant address signal stored in redundant fuse cells 5, 6 and 7.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明はプログラマブル・リード
・オンリ・メモリ(PROM)回路に関し、特に冗長メ
モリの切替え回路に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a programmable read only memory (PROM) circuit, and more particularly to a redundant memory switching circuit.

【0002】[0002]

【従来の技術】従来の冗長メモリ切替え回路は、図2に
示すように、冗長回路活性信号109と、冗長アドレス
信号(冗長メモリ切替えディジタル・アドレス信号)1
11,112および113により選択される冗長ヒュー
ズセル9,10および11と、前記冗長ヒューズセル
9,10,11に書込み信号110で書込みを行なう冗
長ヒューズセル書込み回路8を有している。
2. Description of the Related Art A conventional redundant memory switching circuit includes a redundant circuit activation signal 109 and a redundant address signal (redundant memory switching digital address signal) 1 as shown in FIG.
It has redundant fuse cells 9, 10 and 11 selected by 11, 112 and 113, and a redundant fuse cell write circuit 8 for writing to the redundant fuse cells 9, 10 and 11 with a write signal 110.

【0003】冗長回路活性信号109は、PROM回路
の特定端子への高電圧印加によって選択され、冗長アド
レス信号111,112および113により選択された
ヒューズセル9,10および11は冗長ヒューズセル書
込み回路8から出力される書込み信号110によって書
込まれ、冗長アドレス信号を記憶する。
Redundant circuit activation signal 109 is selected by applying a high voltage to a specific terminal of the PROM circuit, and fuse cells 9, 10 and 11 selected by redundant address signals 111, 112 and 113 are redundant fuse cell write circuit 8. Is written by the write signal 110 output from the memory device to store the redundant address signal.

【0004】[0004]

【発明が解決しようとする課題】この従来のPROM回
路は、特定端子に高電圧を印加することで冗長ヒューズ
セル書込み状態になるので、使用者が誤って前記状態を
選択してしまうと、未書込みの冗長ヒューズセルに誤書
込みを行ない、記憶されていた冗長アドレス信号が変更
されてしまうという問題点があった。
This conventional PROM circuit is in a redundant fuse cell write state by applying a high voltage to a specific terminal. Therefore, if the user erroneously selects the state, the PROM circuit is not written. There is a problem in that the redundant address signal stored in the redundant fuse cell for writing is erroneously written and the stored redundant address signal is changed.

【0005】本発明の目的は、前記問題点が解決され、
記憶されている冗長アドレス信号が変更されてしまうこ
とのないようにしたPROM回路を提供することにあ
る。
The object of the present invention is to solve the above problems,
Another object of the present invention is to provide a PROM circuit in which a stored redundant address signal is not changed.

【0006】[0006]

【課題を解決するための手段】本発明のPROM回路の
構成は、冗長アドレス信号により選択される書込み可能
な第1の半導体記憶素子と、前記第1の半導体記憶素子
に書込みを行なう第1の書込み回路と、前記冗長アドレ
ス信号とは独立した信号で機能する第2の半導体記憶素
子と、前記第2の半導体記憶素子に書込みを行なう第2
の書込み回路と、前記第2の半導体記憶素子の書込み状
態出力信号により前記第1の書込み回路の活性・不活性
を制御する論理回路とを備えたことを特徴とする。
According to the structure of a PROM circuit of the present invention, a writable first semiconductor memory element selected by a redundant address signal and a first writable semiconductor memory element are provided. A write circuit, a second semiconductor memory element that functions as a signal independent of the redundant address signal, and a second semiconductor memory element that writes to the second semiconductor memory element.
And a logic circuit for controlling activation / deactivation of the first write circuit according to a write state output signal of the second semiconductor memory element.

【0007】[0007]

【実施例】次に、本発明について図面を参照して説明す
る。図1は本発明の一実施例のPROM回路を示すブロ
ック図である。図1に示されるように、本実施例は、冗
長ヒューズセル書込み回路4と、冗長ヒューズセル5,
6および7と、前記回路4とは異なる制御ヒューズセル
書込み回路1と、前記冗長ヒューズセル5,6,7とは
異なる制御ヒューズセル2と、AND回路3とを備え
て、構成される。
DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a PROM circuit according to an embodiment of the present invention. As shown in FIG. 1, in this embodiment, the redundant fuse cell write circuit 4, the redundant fuse cells 5,
6 and 7, a control fuse cell write circuit 1 different from the circuit 4, a control fuse cell 2 different from the redundant fuse cells 5, 6 and 7, and an AND circuit 3.

【0008】即ち、本実施例のPROM回路は、冗長メ
モリ切替えディジタル・アドレス信号(以下、冗長アド
レス信号106,107,108とする)により選択さ
れる書込み可能な半導体記憶素子(以下第1のヒューズ
セル5,6,7とする)と、前記第1のヒューズセル
5,6,7に書みを行なう第1の書込み回路4と、前記
冗長アドレス信号106,107,108とは独立した
第2のヒューズセル2と、第2のヒューズセル2に書込
みを行なう第2の書込み回路1と、第2のヒューズセル
2の書込み状態出力信号により第1の書込み回路4の活
性・不活性を制御する論理積回路3とを備えることを特
徴とする。
That is, the PROM circuit of this embodiment is a writable semiconductor memory element (hereinafter referred to as a first fuse) selected by a redundant memory switching digital address signal (hereinafter referred to as redundant address signals 106, 107 and 108). Cells 5, 6, 7), the first write circuit 4 for writing to the first fuse cells 5, 6, 7 and the second address independent of the redundant address signals 106, 107, 108. Fuse cell 2, a second write circuit 1 for writing to the second fuse cell 2, and a write state output signal of the second fuse cell 2 to control activation / inactivation of the first write circuit 4. And a logical product circuit 3.

【0009】図1において、書込み許可信号104は、
冗長回路活性信号103と制御ヒューズセル2からの制
御信号102とのAND論理によって決定されるが、制
御ヒューズセル2にデータが書込まれていない場合、制
御信号102からは論理積“1”が出力されている。特
定端子に高電圧を印加し、冗長回路活性信号103を選
択すると、論理積“1”が出力され、AND回路3によ
り書込み許可信号104に論理値“1”が出力され、冗
長アドレス信号を記憶する冗長ヒューズセル5,6およ
び7へ書込み、冗長ヒューズセル書込み回路4を活性化
させる。冗長ヒューズセル書込み回路4から出力される
書込み信号105によって、冗長アドレス信号106,
107および108により選択された、冗長ヒューズセ
ル5,6および7は、書込まれ、冗長アドレス信号が記
憶される。
In FIG. 1, the write enable signal 104 is
It is determined by the AND logic of the redundant circuit activation signal 103 and the control signal 102 from the control fuse cell 2. However, when data is not written in the control fuse cell 2, the logical product "1" is obtained from the control signal 102. It is being output. When a high voltage is applied to a specific terminal and the redundant circuit activation signal 103 is selected, a logical product “1” is output, the AND circuit 3 outputs a logical value “1” to the write enable signal 104, and the redundant address signal is stored. The redundant fuse cells 5, 6 and 7 are written to activate the redundant fuse cell write circuit 4. By the write signal 105 output from the redundant fuse cell write circuit 4, the redundant address signal 106,
Redundant fuse cells 5, 6 and 7 selected by 107 and 108 are written and redundant address signals are stored.

【0010】一方、制御ヒューズセル2が書込まれてい
た場合は、制御信号102が出力されず、論理値“0”
となり、たとえ、冗長回路活性信号103が選択され、
論理値“1”となっていても、冗長回路活性信号103
と制御信号102との論理積(AND)により、AND
回路3から書込み許可信号104が出力されない。その
ため、冗長ヒューズセル書込み回路4は活性せず、すな
わち書込み信号102は出力されず、冗長ヒューズセル
5,6および7に書込むことはない。
On the other hand, when the control fuse cell 2 is written, the control signal 102 is not output and the logical value is "0".
Therefore, even if the redundant circuit activation signal 103 is selected,
Even if the logical value is "1", the redundant circuit activation signal 103
AND with the control signal 102
The write enable signal 104 is not output from the circuit 3. Therefore, redundant fuse cell write circuit 4 is not activated, that is, write signal 102 is not output, and redundant fuse cells 5, 6 and 7 are not written.

【0011】制御ヒューズセル2に書込む場合は、制御
回路活性信号100を選択し、制御ビューズセル書込み
回路1を活性させ、書込み信号101を出力し、制御ヒ
ューズセル2に書込む。
When writing to the control fuse cell 2, the control circuit activation signal 100 is selected, the control views cell write circuit 1 is activated, the write signal 101 is output, and the control fuse cell 2 is written.

【0012】なお、以上の説明においては、一実施例と
して、冗長ヒューズセルが3ビットの切替え回路に対し
て適用した場合についてであったが、本発明は、ビット
数に制限されることなく、他のPROM回路にしても有
効に適用されることは言うまでもない。
In the above description, the case where the redundant fuse cell is applied to the switching circuit of 3 bits is described as one embodiment, but the present invention is not limited to the number of bits. It goes without saying that other PROM circuits can be effectively applied.

【0013】[0013]

【発明の効果】以上説明したように、本発明は、PRO
M回路に適用されて、制御ヒューズセルに書込みを行な
うことで、冗長ヒューズセル書込み回路の機能を停止さ
せ、冗長回路活性信号を選択状態でも、冗長ヒューズセ
ルへの書込みを禁止し、保護するという効果がある。
As described above, according to the present invention, the PRO
By applying to the M circuit to write to the control fuse cell, the function of the redundant fuse cell write circuit is stopped, and even if the redundant circuit activation signal is selected, writing to the redundant fuse cell is prohibited and protected. effective.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の一実施例のPROM回路を示すブロッ
ク図である。
FIG. 1 is a block diagram showing a PROM circuit according to an embodiment of the present invention.

【図2】従来のPROM回路を示すブロック図である。FIG. 2 is a block diagram showing a conventional PROM circuit.

【符号の説明】[Explanation of symbols]

1 制御ヒューズセル書込み回路 2 制御ヒューズセル 3 AND回路 4,8 冗長ヒューズセル書込み回路 5,6,7,9,10,11 冗長ヒューズセル 100 制御回路活性信号 101 制御ヒューズセル書込み信号 102 制御信号 103,109 冗長回路活性信号 104 書込み許可信号 105,110 冗長ヒューズセル書込み信号 106,107,108,111,112,113
冗長アドレス信号
1 Control Fuse Cell Write Circuit 2 Control Fuse Cell 3 AND Circuit 4,8 Redundant Fuse Cell Write Circuit 5, 6, 7, 9, 10, 11 Redundant Fuse Cell 100 Control Circuit Activation Signal 101 Control Fuse Cell Write Signal 102 Control Signal 103 , 109 redundant circuit activation signal 104 write enable signal 105, 110 redundant fuse cell write signal 106, 107, 108, 111, 112, 113
Redundant address signal

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 冗長アドレス信号により選択される書込
み可能な第1の半導体記憶素子と、前記第1の半導体記
憶素子に書込みを行なう第1の書込み回路と、前記冗長
アドレス信号とは独立した信号で機能する第2の半導体
記憶素子と、前記第2の半導体記憶素子に書込みを行な
う第2の書込み回路と、前記第2の半導体記憶素子の書
込み状態出力信号により前記第1の書込み回路の活性・
不活性を制御する論理回路とを備えたことを特徴とする
PROM回路。
1. A writable first semiconductor memory element selected by a redundant address signal, a first write circuit for writing to the first semiconductor memory element, and a signal independent of the redundant address signal. A second semiconductor memory element that functions in the above, a second write circuit that writes data to the second semiconductor memory element, and a write state output signal of the second semiconductor memory element that activates the first write circuit.・
A PROM circuit comprising a logic circuit for controlling inactivity.
【請求項2】 半導体記憶素子がヒューズセルである請
求項1に記載のPROM回路。
2. The PROM circuit according to claim 1, wherein the semiconductor memory element is a fuse cell.
JP1602493A 1993-02-03 1993-02-03 Prom circuit Pending JPH06231598A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1602493A JPH06231598A (en) 1993-02-03 1993-02-03 Prom circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1602493A JPH06231598A (en) 1993-02-03 1993-02-03 Prom circuit

Publications (1)

Publication Number Publication Date
JPH06231598A true JPH06231598A (en) 1994-08-19

Family

ID=11905000

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1602493A Pending JPH06231598A (en) 1993-02-03 1993-02-03 Prom circuit

Country Status (1)

Country Link
JP (1) JPH06231598A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH097391A (en) * 1995-05-25 1997-01-10 Samsung Electron Co Ltd Fuse element circuit of semiconductor memory device
JP2004030850A (en) * 2002-06-28 2004-01-29 Toshiba Corp Semiconductor storage device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH097391A (en) * 1995-05-25 1997-01-10 Samsung Electron Co Ltd Fuse element circuit of semiconductor memory device
JP2004030850A (en) * 2002-06-28 2004-01-29 Toshiba Corp Semiconductor storage device

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