Dynamic random access memory with fully independent partial array refresh function
View Patent ↗A dynamic random access memory device includes a plurality of memory subblocks. Each subblock has a plurality of wordlines whereto a plurality of data store cells are connected. Partial array self-refresh (PASR) configuration settings are independently made. In accordance with the PASR settings, the memory subblocks are addressed for refreshing. The PASR settings are made by a memory controller. Any kind of combinations of subblock addresses may be selected. Thus, the memory subblocks are fully independently refreshed. User selectable memory arrays for data retention provide effective memory control programming especially for low power mobile application.
1. A dynamic random access memory (DRAM) device comprising:
M memory banks, M being an integer greater than one, each having a plurality of wordlines, each wordline being connected to a plurality of data store cells, the cells being refreshable by a refresh operation; and
a partial array self-refresh configuration register (PASR) for controlling, in a self-refresh mode, the refreshing of each of the M memory banks independently from each other;
a command controller for receiving a command signal and providing a configuration control clock to the PASR, wherein the PASR includes M flip-flops for latching the M-bit refresh data input from M input pins.
2. The DRAM device of claim 1 , wherein
the register contains a respective bit for each memory bank which indicates whether or not, in a self-refresh mode, the memory bank is to be refreshed;
in self-refresh mode, the DRAM device performs a self-refresh operation only for the memory banks for which the respective bit in the register is set to indicate self-refresh.
3. The DRAM device of claim 1 , wherein the register comprises:
M latches, wherein each latch controls the refreshing of a respective one of the M memory banks.
4. The DRAM device of claim 1 , further comprising:
a first address producing circuit for producing N first addresses in the self-refresh mode, N being an integer.
5. The DRAM device of claim 4 , further comprising:
an address controlling circuit for controlling the refreshing of the memory banks in response to the logical combination of the N first addresses and the M-bit refresh data.
6. The DRAM device of claim 5 , wherein the address controlling circuit comprises:
a first address decoding circuit including
M decoding circuits for decoding the first addresses to produce M decoded first address outputs, and
M logic circuits for logically combining the M decoded first address outputs and the M-bit refresh data, thereby producing M first addresses.
7. The DRAM device of claim 6 , further comprising:
a second address producing circuit for producing addresses, the second address producing circuit including M decoding circuits for decoding the second addresses to produce N decoded second addresses.
8. The DRAM device of claim 7 , wherein the first address decoding circuit further includes:
a bank selection circuit having
M selecting circuits for selecting the M decoded first addresses in the refresh mode or the M decoded second addresses in the non-refresh mode, the M selected addresses designating the memory bank to be refreshed.
9. The DRAM device of claim 8 , wherein:
the first address producing circuit comprises an internal address producer for producing internal addresses as the first addresses; and
the second address producing circuit comprises an external address producer for producing external addresses as the second addresses.
10. The DRAM device of claim 9 , wherein:
the command controller controls the latching of the input data by the register and detects the refresh mode, the producing of the address by the address producing circuit and the selection by the bank selection circuit being controlled in response to the detection of the refresh mode.
11. The DRAM device of claim 10 , wherein the command controlling circuit comprises:
a mode detection circuit for detecting a self-refresh mode in the DRAM device.
12. The DRAM device of claim 1 , further comprising:
a first address producing circuit for producing first addresses in the refresh mode; and
a second address producing circuit for producing external addresses.
13. The DRAM device of claim 12 , further comprising:
a bank address controlling circuit for controlling the refreshing of the memory banks in response to the logical combination of the first addresses, the second addresses and the M-bit refresh data.
14. The DRAM device of claim 13 , wherein the bank address controlling circuit comprises:
a selecting circuit for selecting the first addresses in the refresh mode or the second addresses in the non-refresh mode to produce selected addresses.
15. The DRAM device of claim 14 , wherein the bank address controlling circuit further comprises:
an address decoding circuit for decoding the selected addresses to produce M decoded addresses.
16. The DRAM device of claim 15 , wherein the bank address controlling circuit further comprises:
a bank selecting circuit for logically combining the M decoded addresses and the M subblock refresh data to produce M selected addresses designating the memory bank to be refreshed.
17. The DRAM device of claim 16 , wherein:
the selecting circuit comprises N selectors for selecting the N first addresses or the N second addresses to produce N selected addresses;
the address decoding circuit comprises M logic circuits for decoding the N selected addresses to produce M decoded addresses; and
the bank selecting circuit comprises M logic circuits for logically combining the M decoded addresses and the M subblock refresh data to produce the M selected addresses.
18. The DRAM device of claim 17 , wherein:
the first address producing circuit comprises an internal address producer for producing internal addresses as the first addresses; and
the second address producing circuit comprises an external address producer for producing external addresses as the second addresses.
19. The DRAM device of claim 18 , wherein:
the command controller detects the refresh mode, the producing of the address by the address producing circuit and the selection by the selecting circuit being controlled in response to the detection of the refresh mode.
20. A method for refreshing a dynamic random access memory device (DRAM) including M memory banks, M being an integer greater than one, each bank having a plurality of wordlines, each wordline being connected to a plurality of data store cells, the cells being refreshable in a self-refresh mode, the method comprising:
receiving a command signal and providing a configuration control clock to a partial array self-refresh configuration register (PASR) and latching the M-bit refresh data input from M input pins into the M flip-flops of the PASR;
controlling, in the self-refresh mode, the refreshing of each of the M memory banks independently from each other.
21. The method of claim 20 further comprising:
storing in a register a respective bit for each memory bank which indicates whether or not, in a self-refresh mode, the memory bank is to be refreshed;
in self-refresh mode, performing a self-refresh operation only for the memory banks for which the respective bit in the register is set to indicate self-refresh.
22. The method of claim 21 , wherein the step of controlling comprises:
configuring M bank refresh data in response to input data, the M bank refresh data being independently set by the input data, each of the M bank refresh data controlling the refreshing at a respective one of the M memory banks.
23. A refresh controller for use in a dynamic random access memory (DRAM) device selectively operable in a self-refresh mode or a non self-refresh mode, the DRAM device including M memory banks, M being an integer greater that one, each bank having a plurality of wordlines, each wordline being connected to a plurality of data store cells, the cells being refreshable in the self-refresh mode, the refresh controller comprising:
refresh circuitry for controlling in refresh mode the refreshing of the memory banks in accordance with M-bit refresh data from the M input pins independently set;
wherein the refresh circuitry comprises:
a register containing a respective bit for each memory bank which indicates whether or not, in a self-refresh mode, the memory bank is to be refreshed;
wherein in self-refresh mode, the refresh controller controls a self-refresh operation to occur only for the memory banks for which the respective bit in the register is set to indicate self-refresh.
24. A refresh controller for use in a dynamic random access memory (DRAM) device selectively operable in a self-refresh mode or a non self-refresh mode, the DRAM device including M memory banks, M being an integer greater that one, each bank having a plurality of wordlines, each wordline being connected to a plurality of data store cells, the cells being refreshable in the self-refresh mode, the refresh controller comprising:
refresh circuitry for controlling in refresh mode the refreshing of the memory banks in accordance with M-bit refresh data from the M input pins independently set;
configuration circuitry for configuring the M bank refresh data in response to input data, wherein each of the M bank refresh data corresponds to a respective one of the M memory banks.