Variable voltage bit line precharge
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsAtul Katoch, Adrian Earle
Life of this patent
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Abstract
A memory device includes an array of memory cells, a bit line connected to the memory cells, and a power supply voltage input terminal configured to receive a power supply voltage at a first voltage level to operate the memory cells at the first voltage level. A bit line precharge circuit has an input terminal configured to receive the power supply voltage at the first voltage level, and the bit line precharge circuit is configured to precharge the bit lines to a second voltage level lower than the first voltage level.
Claims20
A precharge circuit, comprising:
- a terminal at a first voltage level;
- a first switch connecting the terminal to one or more bit lines;
- one or more second switches connecting the terminal to the one or more bit lines;
- and
- a precharge controller connected to the first switch and the one or more second switches, wherein the precharge controller is configured to actuate the first switch to charge the one or more bit lines to the first voltage level for a first time period, and configured to select a second voltage level lower than the first voltage level and actuate the one or more second switches to charge the one or more bit lines to the second voltage level for a second time period.
A precharge circuit, comprising:
- a terminal at a first voltage level;
- a first transistor connecting the terminal to one or more bit lines, a gate of the first transistor connected to a precharge controller;
- one or more second transistors connected to the terminal, a gate of the one or more second transistors connected to the precharge controller;
- and
- one or more trim devices connecting the one or more second transistors to a bit line, the one or more trim devices including varying threshold voltage types,
- wherein one of the one or more second transistors is selected to charge the bit line to a second voltage level lower than the first voltage level based on a connected corresponding trim device of the one or more trim devices.
A method, comprising:
- connecting a terminal at a first voltage level to a bit line through a first switch;
- determining that a first time period expired;
- disconnecting the terminal from the bit line through the first switch;
- selecting a second switch to connect the terminal to the bit line to bring the bit line to a second voltage level;
- connecting the terminal to the bit line through the second switch and a trim device;
- determining a second time period has expired;
- and
- disconnecting the terminal from the bit line through the second switch and the trim device.
Dependencies are inferred from the claim text.