Adaptive word line pull down
AssigneeFairchild Camera & Instr. Corp.
InventorRoger V. Rufford
Life of this patent
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Abstract
An adaptive word line pull-down circuit steers a pull-down current only to the word being pulled down and only for the time when that word is being pulled down. The time that it takes for the bottom word line to fall controls how long the pull-down current is steered to the falling word.
Claims9
A method for pulling down the word line voltage when a word is to be deaddressed in a memory of the kind having a plurality of words, with each word associated with a top word line and a bottom word line, said method comprising,
- detecting a signal that the address of a word is to be changed,
- amplifying the detected signal,
- steering a pull-down current to the bottom word line to commence pulling the word down in response to the amplified signal,
- maintaining that pull-down current on the bottom word line until the word is deaddressed,
- detecting the fact that the word has been pulled down, and
- steering the pull-down current away from the bottom pull-down line after the word has been deaddressed by detecting and amplifying the voltage of one of the word lines.
Apparatus for pulling down the word line voltage when a word is to be deaddressed in a memory of the kind having a plurality of words and a top word line and a bottom word line associated with each word, said apparatus comprising,
- detecting means for detecting a signal that the address of a word is to be changed,
- amplifying means operatively associated with the detecting means for amplifying the detected signal,
- steering means operatively associated with the amplifying means for steering a pull-down current to the bottom word line to commence pulling the word down in response to the amplified signal and for maintaining that pull-down current on the bottom word line until the word is deaddressed,
- said amplifying means including current switch means operatively associated with a word line for detecting the fact that the word has been pulled down and effective to cause the level shifter and steering means to steer the pull-down current away from the bottom pull-down line after the word has been deaddressed.
Dependencies are inferred from the claim text.