SRAM with improved write operation
View Patent ↗A memory including an array of memory cells, word lines, and voltage supply lines. Each voltage supply line of the plurality of voltage supply lines is coupled to a first voltage supply terminal of a subset of memory cells of subsets of memory cells of the array. Each memory cell of the array is coupled to a word line. The memory includes a row decoder that controls a voltage on each of the word lines and controls a voltage on each of the voltage supply lines. The row decoder provides a low voltage state voltage on one of the voltage supply lines during a write operation to a subset of memory cells coupled to the voltage supply line and the row decoder provides a high voltage state voltage to the voltage supply line during a read operation of the subset of the memory cells.
1. A memory comprising:
an array of memory cells, wherein each memory cell of the array includes a first supply voltage terminal and a second supply voltage terminal;
a plurality of word lines, wherein each memory cell of the array is coupled to a word line of the plurality of word lines;
a plurality of voltage supply lines, each voltage supply line of the plurality of voltage supply lines is coupled to a first voltage supply terminal of a subset of memory cells of a plurality of subsets of memory cells of the array, wherein each subset of the plurality of subsets includes a plurality of memory cells;
a row decoder, the row decoder controls a voltage on each of the plurality of word lines, the row decoder controls a voltage on each of the plurality of voltage supply lines, wherein during at least one mode of operation, for each voltage supply line of the plurality of voltage supply lines, the row decoder provides a low voltage state voltage on a voltage supply line of the plurality of voltage supply lines during a write operation to a subset of memory cells of the plurality of subsets coupled to the voltage supply line and the row decoder provides a high voltage state voltage to the voltage supply line during a read operation of the subset of the memory cells.
2. The integrated circuit of claim 1 wherein the subsets of the plurality of subsets are characterized as rows of memory cells of the array.
3. The memory of claim 1 wherein for each voltage supply line of the plurality of voltage supply lines, a voltage provided on a voltage supply line coupled to a subset of memory cells of the plurality of subsets is dependent upon a voltage provided on a word line of the plurality of word lines that is coupled to the subset of memory cells.
4. The memory of claim 3 wherein the row decoder includes a plurality of logic circuits, each logic circuit of the plurality of logic circuits including an output for controlling a voltage of a voltage supply line of the plurality of voltage supply lines, wherein each logic circuit includes an input coupled to a word line of the plurality of word lines that is coupled to a subset of memory cells of the plurality of subsets that the voltage supply line is coupled to.
5. The memory of claim 4 wherein each logic circuit of the plurality of logic circuits performs a logical NAND operation with a word line coupled to the input of the logic circuit being an input of the logical NAND operation and the output of the logic circuit being an output of the logical NAND operation.
6. The memory of claim 5 wherein a write/read signal is a second input of the logical NAND operation for each logic circuit of the plurality of logic circuits.
7. The memory of claim 4 wherein each logic circuit of the plurality of logic circuits performs a logic inverter function with a word line coupled to the input of the logic circuit being an input of the logic inverter function and the output of the logic circuit being an output of the logic inverter function, such that a voltage supply line of the plurality of voltage supply lines coupled to the output of the logic circuit is provided at an inverted voltage state to a voltage state of the word line coupled to the input of the logic circuit.
8. The memory of claim 1 wherein during at least one mode of operation, for each voltage supply line of the plurality of voltage supply lines, the row decoder provides a low voltage state voltage on a voltage supply line of the plurality of voltage supply lines coupled to a subset of the plurality of subsets during a write operation to the memory cells of the subset while providing a high voltage state voltage on a word line of the plurality of word lines that is coupled to the subset.
9. The memory of claim 1 wherein the memory cells of the array are characterized as 6T SRAM memory cells.
10. The memory of claim 1 wherein the plurality of word lines are characterized as write word lines, wherein the memory includes a plurality of read word lines wherein each memory cell of the array is coupled to a read word line of the plurality of read word lines.
11. The memory of claim 1 , wherein the row decoder provides a high voltage state voltage on voltage supply lines of the plurality of voltage supply lines coupled to subsets of the plurality of subsets not being written to during a during a write operation to a subset of the plurality of subsets.
12. The memory of claim 1 wherein in at least one mode of operation, for each memory cell of the array, the first supply voltage terminal receives a higher voltage than the second supply voltage terminal during a read operation of the memory cell.
13. A method for operating a memory comprising:
performing a write operation to a plurality of memory cells, wherein each cell of the plurality of memory cells is coupled to a word line, each cell of the plurality of memory cells includes a voltage supply terminal coupled to a voltage supply line, wherein during the write operation, a voltage at a high voltage state is provided on the word line and a voltage at a low voltage state is provided on the voltage supply line;
performing a read operation of the plurality of memory cells, wherein during the read operation, a voltage at a high voltage state is provided on the voltage supply line.
14. The method of claim 13 wherein a voltage of the voltage supply line is produced by performing a logical NAND function where a voltage of the word line is an input of the logical NAND function.
15. The method of claim 14 , wherein a write/read signal is a second input of the logical NAND function.
16. The method of claim 13 wherein during the write operation and read operation, the voltage state of the word line is an opposite voltage state of the voltage supply line.
17. The method of claim 13 wherein the memory cells of the plurality of memory cells each include a read port and the word line is characterized as a write word line.
18. The method of claim 13 wherein during the write operation, the voltage state of the word line is an opposite voltage state of the voltage supply line.
19. A memory comprising:
an array of SRAM memory cells, wherein each memory cell of the array includes a first supply voltage terminal and a second supply voltage terminal;
a plurality of word lines, wherein each memory cell of the array is coupled to a word line of the plurality of word lines;
a plurality of voltage supply lines, each voltage supply line of the plurality of voltage supply lines is coupled to a first voltage supply terminal of a subset of memory cells of a plurality of subsets of memory cells of the array, wherein each subset of the plurality of subsets includes a plurality of memory cells;
a row decoder, the row decoder controls a voltage on each of the plurality of word lines, the row decoder controls a voltage on each of the plurality of voltage supply lines, wherein during at least one mode of operation, for each voltage supply line of the plurality of voltage supply lines, the row decoder provides a low voltage state voltage on a voltage supply line of the plurality of voltage supply lines coupled to a subset of the plurality of subsets during a write operation to the memory cells of the subset while providing a high voltage state voltage on a word line of the plurality of word lines that is coupled to the subset.
20. The memory of claim 19 wherein during at least one mode of operation for each memory cell of the array, the first supply voltage terminal receives a higher voltage than the second supply voltage terminal during a read operation of the memory cell.