Non-volatile latch with low voltage operation
View Patent ↗Methods, circuits, devices, and/or arrangements for providing a non-volatile latch are disclosed. In one embodiment, a non-volatile latch can include: (i) a first non-volatile memory (NVM) cell coupled to a first supply, a first gate (e.g., a control gate), and an output node, where the first NVM cell is configured to be in a first state; and (ii) a second NVM cell coupled to a second supply, a second gate (e.g., another control gate), and the output node, where the second NVM cell is configured to be in a second state.
1. A non-volatile latch, comprising:
a) a first non-volatile memory (NVM) cell connected to a first supply, a first gate, and an output node, wherein said first NVM cell is configured to be in a first state; and
b) a second NVM cell connected to a second supply, a second gate, and said output node, wherein said second NVM cell is configured to be in a second state, wherein said first and second gates are independently controllable.
2. The non-volatile latch of claim 1 , wherein said first and second supplies are configured to be variable depending on a mode of operation.
3. The non-volatile latch of claim 1 , further comprising a protection transistor coupled in series between said first NVM cell and said first supply.
4. The non-volatile latch of claim 1 , further comprising a protection transistor coupled in series between said second NVM cell and said second supply.
5. The non-volatile latch of claim 1 , further comprising:
a) a first protection transistor coupled in series between said first NVM cell and said first supply; and
b) a second protection transistor coupled in series between said second NVM cell and said second supply.
6. The non-volatile latch of claim 1 , wherein said first and second NVM cells each comprise a conductive material charge storage layer.
7. The non-volatile latch of claim 6 , wherein said conductive material charge storage layer comprises polysilicon.
8. The non-volatile latch of claim 6 , wherein said conductive material charge storage layer comprises metal.
9. The non-volatile latch of claim 1 , wherein said first and second NVM cells each comprise a dielectric material charge storage layer.
10. The non-volatile latch of claim 9 , wherein said dielectric material charge storage layer comprises a high-k dielectric.
11. The non-volatile latch of claim 9 , wherein said dielectric material charge storage layer comprises nitride or oxynitride.
12. The non-volatile latch of claim 1 , wherein said first and second NVM cells each comprise a charge storage layer having nanocrystals.
13. The non-volatile latch of claim 1 , wherein said first and second NVM cells each are configured to be programmed using channel hot electron (CHE) injection.
14. The non-volatile latch of claim 13 , wherein said configured to be programmed comprises said first or said second supply at about 5 V, said output node at about 0 V, and said first or said second gate at about 5.5 V.
15. The non-volatile latch of claim 1 , wherein said first and second NVM cells each are configured to be erased using channel-induced hot hole (CHH) injection.
16. The non-volatile latch of claim 15 , wherein said configured to be erased comprises said first or said second supply at about 5 V, said output node at about 0 V, and said first or said second gate at about 2 V.
17. The non-volatile latch of claim 15 , wherein said configured to be erased further comprises ramping down a voltage on said first or said second gate.
18. The non-volatile latch of claim 17 , wherein said ramping down said voltage on said first or said second gate comprises using a staircase function.
19. The non-volatile latch of claim 1 , wherein said first state is ON, and said second state is OFF.
20. The non-volatile latch of claim 1 , wherein said first state is OFF, and said second state is ON.
21. The non-volatile latch of claim 1 , wherein said first and second states are ON.
22. The non-volatile latch of claim 1 , wherein said first and second states are OFF.
23. The non-volatile latch of claim 1 , wherein said output node is configured to control a transistor.
24. The non-volatile latch of claim 1 , wherein said output node is configured to control an inverter, latch, SRAM cell, or combinations thereof.
25. A method of operating a non-volatile latch, comprising the steps of:
a) receiving an indication for accessing said non-volatile latch, said non-volatile latch including a first non-volatile memory (NVM) cell coupled in series with a second NVM cell, wherein said first and second NVM cells are independently controllable using separate gates;
b) when said indication is a latch state set indication, programming said first NVM cell and erasing said second NVM cell;
c) when said indication is a latch state reset indication, erasing said first NVM cell and programming said second NVM cell; and
d) when said indication is a latch state read indication, biasing each of said gates to read said latch state on an output node.
26. The method of claim 25 , further comprising generating said latch state read indication in response to chip power-up.
27. The method of claim 25 , wherein said programming comprises using channel hot electron (CHE) injection.
28. The method of claim 25 , wherein said erasing comprises using channel-induced hot hole (CHH) injection.
29. An electrically erasable programmable read-only memory (EEPROM) device, comprising:
a) a controller configured to control programming, erasing, and reading of a memory portion; and
b) said memory portion having a plurality of non-volatile latches, wherein each said non-volatile latch includes a first non-volatile memory (NVM) cell connected to a first supply, a first gate, and an output node, and wherein said first NVM cell is configured to be in a first state, and a second NVM cell connected to a second supply, a second gate, and said output node, wherein said second NVM cell is configured to be in a second state, wherein said first and second gates are independently controllable.
30. The EEPROM device of claim 29 , further comprising an array of NVM cells.
31. The EEPROM device of claim 29 , further comprising an array of static random-access memory (SRAM) cells.
32. The EEPROM device of claim 29 , wherein said first state is ON, and said second state is OFF.
33. The EEPROM device of claim 29 , wherein said first state is OFF, and said second state is ON.
34. The EEPROM device of claim 29 , wherein said first and second states are ON.
35. The EEPROM device of claim 29 , wherein said first and second states are OFF.
36. A method of operating a non-volatile latch, comprising the steps of:
a) receiving an indication for accessing said non-volatile latch, said non-volatile latch including a first non-volatile memory (NVM) cell coupled in series with a second NVM cell, wherein said first and second NVM cells are independently controllable using separate gates;
b) when said indication is a latch state set or reset indication, performing a non-selective operation on both said first and said second NVM cells, and performing a selective operation on either of said first or said second NVM cells; and
c) when said indication is a latch state read indication, biasing each of said gates to read said latch state on an output node.
37. The method of claim 36 , wherein said non-selective operation comprises programming.
38. The method of claim 37 , wherein:
a) when said indication is a latch state set indication, erasing said second NVM cell; and
b) when said indication is a latch state reset indication, erasing said first NVM cell.
39. The method of claim 36 , wherein said non-selective operation comprises erasing.
40. The method of claim 39 , wherein:
a) when said indication is a latch state set indication, programming said first NVM cell; and
b) when said indication is a latch state reset indication, programming said second NVM cell.