Memory device and method thereof
View Patent ↗The present application discloses a memory array where each memory bit cell of the array includes a level shifter. In addition, each memory bit cell includes a write port that includes pass gate that can include a p-type field effect transistor and an n-type field effect transistor. The control electrodes of the p-type field effect transistor and the n-type field effect transistor are connected together as part of a common node. In addition, a current electrode of the p-type field effect transistor and a current electrode of the n-type field effect transistor are connected together to form a common node.
1. A device comprising:
a memory array comprising a plurality of memory bit cells, each memory bit cell of the plurality of memory bit cells comprising:
a storage cell to store a bit of information; and
a level shifter comprising a first node coupled to the storage cell to receive a first voltage during a read operation representing the bit of stored information stored at the storage cell, and a second node to provide a second voltage representing the bit of stored information, where a magnitude of the first voltage is different than a magnitude of the second voltage.
2. The device of claim 1 wherein each memory bit cell further comprises:
a write port comprising a bit line node to receive a bit of information to be stored at the memory bit cell during a write operation, a write line node to receive a write enable signal that is asserted during the write operation, and a first node coupled to the second node of the level shifter to receive a third voltage representing the bit of information to be stored.
3. The device of claim 2 , wherein the write port further comprises a second node coupled to a first storage node of the storage cell to communicate a fourth voltage representing the bit of information to be stored to the first storage node during the write operation.
4. The device of claim 2 , wherein the write port further comprises a first transistor comprising a first current electrode, a second current electrode, and a control electrode, where the first transistor is a transistor of a first conductivity type, and the bit line node comprises the first current electrode and the write line node comprises the control electrode.
5. The device of claim 4 , wherein the write port further comprises a second transistor comprising a first current electrode, a second current electrode coupled to the second current electrode of the first transistor, and a control electrode coupled to the write line node, where the second transistor is a transistor of a second conductivity type, opposite than the first conductivity type.
6. The device of claim 5 , wherein the transistor of the first conductivity type is a PFET transistor, and the transistor of the second conductivity type is an NFET transistor.
7. The device of claim 4 , wherein the write port further comprises a second transistor comprising a first current electrode, a second current electrode coupled to the second current electrode of the first transistor, and a control electrode coupled to the write line node.
8. The device of claim 7 , wherein the level shifter further comprises a third transistor comprising a first current electrode, a second current electrode, and a control electrode, where the first node of the level shifter comprises the first current electrode, and the second node of the level shifter comprises the second current electrode.
9. The device of claim 8 , wherein the write port further comprises a fourth transistor comprising a first current electrode, a second current electrode, and a control electrode coupled to the second current electrode of the first transistor of the write port.
10. The device of claim 8 , wherein the first node of the level shifter is coupled to a first storage node of the storage cell, and the write port further comprises:
a second node coupled to a second storage node of the storage cell to communicate a fourth voltage to the second storage node during the write operation that is based upon the information received at the bit line node; and
a fourth transistor comprising a first current electrode, a second current electrode, and a control electrode coupled to the second current electrode of the first transistor, where the second node of the write port comprises the first current electrode.
11. The device of claim 10 wherein the third voltage represents a first logic value and the fourth voltage represents a second logic value complementary to the first logic value.
12. The device of claim 1 , wherein the level shifter further comprises a second node to receive a low power indicator, wherein the second voltage is to represent the bit of stored information in response to the low power indicator being negated, and the second signal does not represent the bit of stored information in response to the low power indicator being asserted.
13. The device of claim 1 , wherein the level shifter further comprises a first transistor comprising a first current electrode, a second current electrode, and a control electrode, wherein the first node comprises the first current electrode, and the second node comprises the second current electrode.
14. A device comprising:
a memory array comprising a plurality of memory bit cells, each memory bit cell of the plurality of bit cells comprising:
a first write port comprising
a first transistor comprising a first current electrode coupled to receive information from a first bit line node to be stored at a memory bit cell of the plurality of memory bit cells, a second current electrode to receive the second information from the first current electrode in response to a first write indicator being enabled, and a control electrode to receive the first write indicator, where the first transistor is a PFET transistor; and
a second transistor comprising a first current electrode coupled to a voltage reference node to receive a reference voltage during a first write operation, a second current electrode coupled to the second current electrode of the first transistor, and a control electrode coupled to the control electrode of the first transistor, where the second transistor is an NFET transistor.
15. The device of claim 14 further comprising:
a second write port comprising
a first transistor comprising a first current electrode coupled to receive second information from a second bit line to be stored at the bit cell, a second current electrode to receive the second information from the first current electrode in response to a second write indicator being enabled, and a control electrode to receive the second write indicator, where the first transistor is a PFET transistor; and
a second transistor comprising a first current electrode coupled to the voltage reference node to receive the reference voltage during a second write operation, a second current electrode coupled to the second current electrode of the first transistor, and a control electrode coupled to the control electrode of the first transistor.
16. The device of claim 14 wherein the first write port further comprises:
a third transistor comprising a first current electrode coupled to the memory bit cell, a second current electrode, and a control electrode coupled to the second current electrode of the first transistor.
17. The device of claim 16 wherein the first write port further comprises:
a fourth transistor comprising a first current electrode coupled to the memory bit cell, a second current electrode, and a control electrode coupled to the second current electrode of the first transistor.
18. The device of claim 16 further comprising a level shifter having a first node to receive a first high-level voltage from the bit cell representative of a logic state, and a second node to provide second high-level voltage from the level shifter representative of the logic state, where the first high-level voltage has a magnitude greater than the second high-level voltage.
19. A method comprising:
receiving an asserted write enable signal during a write operation;
turning on a first transistor in response to receiving the asserted write enable signal to communicate information at a first electrode of the first transistor to a node that comprises the second electrode of the first transistor, the information to be stored at a storage cell; and
turning off a second transistor in response to receiving the asserted write enable signal;
receiving a negated write enable signal during a read operation;
turning on the second transistor in response to receiving the negated write enable signal to communicate a reference signal to a first electrode of the second transistor to the node.
20. The method of claim 19 further comprising:
during the write mode, shifting, at a memory bit cell, a first high-voltage level at a storage node of the memory bit cell to a second high-voltage level.