CONTROLLER AND CONTROL METHOD FOR DYNAMIC RANDOM ACCESS MEMORY
First Claim
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1. A dynamic random access memory controller, comprising:
- a command queue with access commands queued therein, wherein the access commands are queued in the command queue waiting to be transmitted to a dynamic random access memory; and
a microcontroller, using a counter to count how many times a rank of the dynamic random access memory is entirely refreshed,wherein;
the microcontroller repeatedly performs a per-rank refresh operation on the rank when the counter has not reached an upper limit and no access command corresponding to the rank is waiting in the command queue; and
the microcontroller decreases the counter by 1 every refresh inspection interval.
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Abstract
A schedule for refreshing a dynamic random access memory (DRAM). Access commands for a DRAM are queued in a command queue. A microcontroller uses a counter to count how many times a rank of the DRAM is refreshed entirely (whether by a one-time per-rank refresh operation or by a series of per-bank refresh operations). When the counter has not reached an upper limit and no access command corresponding to the rank is waiting in the command queue, the microcontroller repeatedly performs the per-rank refresh operation on the rank. Every refresh inspection interval, the microcontroller decreases the counter by 1.
1 Citation
20 Claims
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1. A dynamic random access memory controller, comprising:
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a command queue with access commands queued therein, wherein the access commands are queued in the command queue waiting to be transmitted to a dynamic random access memory; and a microcontroller, using a counter to count how many times a rank of the dynamic random access memory is entirely refreshed, wherein; the microcontroller repeatedly performs a per-rank refresh operation on the rank when the counter has not reached an upper limit and no access command corresponding to the rank is waiting in the command queue; and the microcontroller decreases the counter by 1 every refresh inspection interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A control method for dynamic random access memory, comprising:
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providing a command queue with access commands queued therein, wherein the access commands are queued in the command queue waiting to be transmitted to a dynamic random access memory; using a counter to count how many times a rank of the dynamic random access memory is entirely refreshed; repeatedly performing a per-rank refresh operation on the rank when the counter has not reached an upper limit and no access command corresponding to the rank is waiting in the command queue; and decreasing the counter by 1 every refresh inspection interval. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification