Temperature based DRAM refresh
View Patent ↗A system for controlling the refresh cycles of a DRAM cell array based upon a temperature measurement. During active mode, a refresh request indication based on a measured temperature is provided to a DRAM controller (e.g. of another integrated circuit die), wherein the DRAM controller initiates a refresh cycle of the DRAM cell array in response thereto. In a self refreshing mode, the DRAM controller does not initiate refresh cycles, but refresh cycles are performed by a controller on the integrated circuit die of the array based upon a temperature measurement.
1. A method for refreshing DRAM cells, the method comprising:
operating in an active mode wherein in the active mode:
sensing a temperature with a temperature sensor located on a same integrated circuit die as an array of dynamic random access memory (DRAM) cells;
providing a first indication to initiate a refresh cycle to first control circuitry, the first indication based on a temperature measured by the temperature sensor;
providing a second indication by the first control circuitry to initiate a refresh cycle of the array based on the first indication;
refreshing the array as per the second indication from the first control circuitry;
operating in a self refresh cycle mode:
sensing a temperature with the temperature sensor;
initiating a refresh of the array by a second control circuitry based on a temperature measured by the temperature sensor;
refreshing the array as per the initiating;
providing an indication by the first control circuitry to initiate a refresh cycle of a second array of dynamic random access memory (DRAM) cells;
refreshing the second array as per the indication from the first control circuitry;
wherein the refreshing the array is performed using a first address generator;
wherein the refreshing the second array is performed using a second address generator.
2. The method of claim 1 wherein the second control circuitry is located on the same integrated circuit die as the array and temperature sensor, wherein the first control circuitry is located on a second integrated circuit die.
3. The method of claim 1 wherein the providing the second indication by the first control circuitry is based upon an opportunity to run a refresh cycle of the array.
4. The method of claim 3 wherein the opportunity is at a time when read or write accesses are not being made to the array.
5. The method of claim 1 wherein the providing the second indication includes providing a refresh command.
6. The method of claim 5 wherein the refresh command is received by circuitry on the same integrated circuit die as the array and wherein the first control circuitry is on a different integrated circuit die.
7. The method of claim 1 wherein the refreshing the array as per the second indication from the first control circuitry and the refreshing the array as per the initiating is performed using an address generator located on the same integrated circuit die as the array.
8. The method of claim 1 wherein the first control circuitry and the second control circuitry is located in a same IC package.
9. The method of claim 1 wherein the first control circuitry and the second control circuitry are located on the same integrated circuit die.
10. The method of claim 1 wherein data read accesses and data write accesses can be made to the array during the active mode and data read accesses and data write accesses can not be made to the array during the self refresh mode.
11. The method of claim 1 wherein the refreshing the array as per the second indication from the first control circuitry when operating the active mode further includes performing an auto refresh cycle.
12. The method of claim 2 wherein the second array is located on a third integrated circuit die.
13. The method of claim 12 wherein the third integrated circuit die includes a second temperature sensor.
14. A method for refreshing DRAM cells, the method comprising:
operating in an active mode wherein in the active mode:
sensing a temperature with a temperature sensor located on a same integrated circuit die as an array of dynamic random access memory (DRAM) cells;
providing a first indication to initiate a refresh cycle to first control circuitry, the first indication based on a temperature measured by the temperature sensor;
providing a second indication by the first control circuitry to initiate a refresh cycle of the array based on the first indication, wherein the first control circuitry is located on a second integrated circuit die;
refreshing the array as per the second indication from the first control circuitry;
operating in a self refresh cycle mode:
sensing a temperature with the temperature sensor;
initiating a refresh of the array by a second control circuitry based on a temperature measured by the temperature sensor, wherein the second control circuitry is located on the same integrated circuit die as the array and temperature sensor, wherein in the self refresh cycle mode, the initiating a refresh is performed independent of the first control circuitry;
refreshing the array as per the initiating.
15. The method of claim 14 wherein the providing the second indication by the first control circuitry is based upon an opportunity to run a refresh cycle of the array.
16. The method of claim 15 wherein the opportunity is at a time when read or write accesses are not being made to the array.
17. The method of claim 14 wherein the providing the second indication includes providing a refresh command.
18. The method of claim 17 wherein the refresh command is received by circuitry on the same integrated circuit die as the array and wherein the first control circuitry is on a different integrated circuit die.
19. The method of claim 14 wherein the refreshing the array as per the second indication from the first control circuitry and the refreshing the array as per the initiating is performed using an address generator located on the same integrated circuit die as the array.
20. The method of claim 14 wherein the first control circuitry and the second control circuitry is located in a same IC package.
21. The method of claim 14 wherein data read accesses and data write accesses can be made to the array during the active mode and data read accesses and data write accesses can not be made to the array during the self refresh mode.
22. The method of claim 14 wherein the refreshing the array as per the second indication from the first control circuitry when operating the active mode further includes performing an auto refresh cycle.
23. The method of claim 14 further comprising:
providing an indication by the first control circuitry to initiate a refresh cycle of a second array of dynamic random access memory (DRAM) cells;
refreshing the second array as per the indication from the first control circuitry;
wherein the refreshing the array is performed using a first address generator;
wherein the refreshing the second array is performed using a second address generator.
24. The method of claim 14 further comprising: generating data accesses to the array by the first control circuitry.