IP Library Granted Patent US 6,885,601
Granted Patent B2
US 6,885,601 · App. 10/747,241 · Granted Apr 26, 2005

Memory circuit and method of reading data

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Quick Facts
Patent No.
US 6,885,601
App. No.
10/747,241
Granted
Apr 26, 2005
Kind
B2
Abstract

Malfunction caused by a parasitic capacitance generated between bit lines is prevented. Dummy bit lines are arranged opposite to an address decoder while sandwiching a date storage section. The dummy bit lines are arranged such that the both right and left dummy bit lines having cell transistors sandwich the central dummy bit line having no cell transistor.

Claims (20)

1. A memory circuit comprising:

an address decoder;

a data storage section connected to said address decoder by a plurality of word lines;

a voltage stable detection section connected to said address decoder by the plurality of word lines and also connected to said address decoder via said data storage section;

said voltage stable detection section made up of a first dummy bit line having no cell transistor corresponding to intersections between itself and the plurality of word lines at each intersection and second dummy bit lines having cell transistors corresponding to intersections between themselves and the plurality of word lines at each intersection.

2. The memory circuit according to claim 1 , wherein a gate, a source, and a drain of each cell transistor are connected to a corresponding word line, a corresponding bit line, and the ground, respectively.

3. The memory circuit according to claim 1 , further comprising:

a pre-charge circuit connected to said data storage section and said voltage stable detection section;

a level detection circuit connected to said data storage section; and

a latch circuit connected to said level detection circuit.

4. The memory circuit according to claim 1 , wherein said second dummy bit lines are provided at both sides of said first dummy bit line.

5. The memory circuit according to claim 1 , wherein a plurality of second dummy bit lines are provided at both sides of said first dummy bit line.

6. The memory circuit according to claim 1 , wherein said voltage stable detection section is arranged opposite to said address decoder while sandwiching said data storage section.

7. A method of reading data comprising the steps of:

supplying an electric charge to a plurality of bit lines of a data storage section comprising the plurality of bit lines and a plurality of word lines;

supplying the electric charge to first and second dummy bit lines of a voltage stable detection section made up of the first dummy bit line having no cell transistor corresponding to intersections between itself and the plurality of word lines, and the second dummy bit lines having cell transistors corresponding to intersections between themselves and the plurality of word lines, said first and second dummy bit lines being arranged side-by-side;

supplying the electric charge to the plurality of word lines of said data storage section, and subsequently supplying the electric charge to the plurality of word lines of said voltage stable detection section; and

reading data from said data storage section when the voltage of the first and second dummy bit lines are stabilized after supplying the electric charge to the plurality of word lines of said voltage stable detection section.

8. The method of reading data according to claim 7 , further comprising the step of selecting a structure of said voltage stable detection section made up of said first dummy bit line and said second dummy bit lines arranged at both sides of said first dummy bit line.

9. The method of reading data according to claim 7 , further comprising the step of selecting a structure of said voltage stable detection section made up of said first dummy bit line and a plurality of said second dummy bit lines arranged at both sides of said first dummy bit line.

Assignments (2)
CHANGE OF NAME Recorded Dec 18, 2008
From: OKI ELECTRIC INDUSTRY CO., LTD.
To: OKI SEMICONDUCTOR CO., LTD.
Reel/Frame 022038/0711 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 30, 2003
From: NAGATA, SATOSHI
To: OKI ELECTRIC INDUSTRY CO., LTD.
Reel/Frame 014855/0344 →