Non volatile memory device architecture and corresponding programming method
View Patent ↗A non volatile memory device architecture, suitable for speeding up and synchronize the programming steps of the cells in particular of the Flash-Nor type, of the type comprising a matrix of memory cells organized into rows and columns, at least one group of these columns being selected by at least one first enable signal by a second enable signal generated by a first decoder; the group of columns being associated with at least one Program Load PL controlled by a logic circuit comprising a first centralized portion and plural second portions associated with a respective program load sequentially updated and driven in a synchronous way to the first centralized portion.
1. A non-volatile memory comprising:
a matrix of memory cells including rows and columns;
a logic circuit to program selected cells, said circuit including a central portion and a plurality of second output portions, said logic to indicate a first selection of a row and sequentially select successive columns on said selected row;
a discharge circuit to activate a discharge signal, said discharge circuit connected to a column and to ground; and
said logic circuit to pulse program a cell in a selected column and row by means of a specific second output portion to update a program load, a second update for the central portion and a third sequential update of the plurality of second portions.
2. The architecture of claim 1 further comprising a logic gate activated by an update signal which allows the communication between the central portion and the plurality of second portions by means of a bus.
3. The architecture of claim 2 wherein each of the plurality of second portions comprises a first latch register, connected to the bus, and activated by a first control signal and a second latch register in cascade to the first latch connected to the program load and activated by a second control signal.
4. The architecture of claim 3 wherein the central portion comprises a plurality of latch registers, suitable for storing possible switches of the cells of the at least one group of columns, a multiplexer in cascade to the plurality of latch registers with an output connected to the logic gate.
5. The architecture of claim 4 wherein the multiplexer is driven by the first address signal and that the central portion comprises a decoder controlled by the second address signal which drives sequentially the plural second portions.
6. The architecture of claim 5 wherein each of the plural second portions comprises a second logic gate whose inputs are the second address signal output from the decoder and a synchronization signal and whose output is connected to the first Latch register, the output providing the first control signal.
7. The architecture of claim 6 wherein the first address signal and the second address signal are synchronized and activated by means of the synchronization signal.
8. The architecture of claim 1 wherein the plural second portions are sequentially activated and are at the maximum in the number of J and that the number J is function of the number of the Program Loads programmable in series by the logic circuit.
9. A method for programming a non volatile memory device with matrix of memory cells, organized into rows and columns, at least one group of the columns being selected by means of a first decoder, at least one program load controlled by a logic circuit and suitable for programming the cells of an activated column of the at least one group, the logic circuit comprising a central portion centralized for the matrix and plural second output portions each specific for each Program Load, the method comprising the steps of:
a first selection which provides to select a row of the matrix and in a sequential way the active columns of the group by means of a first enable signal and at least one second select signal generated by the first decoder;
a discharge step which provides to activate a discharge signal suitable for activating a discharge circuit connected between the columns of the group and a ground reference;
a programming step which comprises
a first update step which provides to update the program Load for a pulse programming of one cell of the activated column by means of a specific second output portion;
a second update step of the central portion and
a third sequential update step of the plural second portions.
10. The method of claim 9 wherein the second update step and the third update step are synchronized.
11. The method of claim 10 wherein the second update step comprises the activation of a first address signal which drives the central portion while the third update step comprises the activation of a second address signal which sequentially drives the plural second portions.
12. The method of claim 11 wherein the first and second address signal are generated by a second decoder independently from the first decoder.
13. The method of claim 12 wherein the second address signal is a processing of the first address signal.
14. The method of claim 13 wherein the programming step comprises an enable step which allows the activation of the second and the third update step.
15. The method of claim 14 wherein the enable step provides the activation of an update signal which allows to prepare the communication by means of the bus between the central portion and each of the plural second portions.
16. The method of claim 15 wherein each of the plural second portions comprises a first and a second latch register connected to each other and activated separately by a first control signal and by a second control signal, the second control signal being activated during the first update step.
17. The method of claim 16 wherein the first and second update steps are activated in parallel to the deactivation of the first update step.
18. The method of claim 17 wherein the synchronization provides to sequentially activate the plural second portions by means of the activation of the second address signal according to a synchronization signal to generate the first control signal.
19. The method of claim 18 wherein the synchronization comprises an update of the central portion by means of the first address signal which drives a multiplexer in cascade to a plurality of latches registers and connected to a logic gate activated by the update signal and connected to the bus.