Method for driving a semiconductor device including data migration between a volatile memory and a nonvolatile memory for power-saving
First Claim
1. A method for driving a semiconductor device including a volatile memory and a nonvolatile memory, the method comprising the steps of:
- operating the volatile memory with a normal mode;
monitoring access requirements to the volatile memory and detecting an access frequency of the volatile memory;
comparing a used space of the volatile memory and an available space of the nonvolatile memory when the access frequency of the volatile memory is smaller than a first set value;
forwarding data stored in the volatile memory to the nonvolatile memory when the used space of the volatile memory is smaller than the available space of the nonvolatile memory;
changing the volatile memory from the normal mode to a stop mode;
monitoring access requirements to the nonvolatile memory and measuring a data transferring speed of the nonvolatile memory;
returning the volatile memory from the stop mode to the normal mode when the data transferring speed of the nonvolatile memory is higher than a second set value; and
forwarding part of data in the volatile memory to the nonvolatile memory when an available space of the volatile memory is smaller than a third set value,wherein the third set value is configured to be changed depending on temperature of the volatile memory;
wherein the normal mode is a mode supplying a first power supply voltage to the volatile memory, andwherein the stop mode is a mode not supplying any power supply voltage to the volatile memory.
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Accused Products
Abstract
To reduce power consumption of a processing device including a processor and a main memory in the processor. The main memory includes not only a volatile memory such as a DRAM but also a nonvolatile memory. The processor monitors access requirements to the main memory. The processor determines on the basis of the monitoring results whether the volatile memory or the nonvolatile memory operates mainly. In the case where the main memory changes from the volatile memory to the nonvolatile memory, part or all of data stored in the volatile memory is backed up to the nonvolatile memory. While the nonvolatile memory operates mainly, supply of power supply voltage to the volatile memory is stopped or power supply voltage to be supplied is lowered.
17 Citations
7 Claims
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1. A method for driving a semiconductor device including a volatile memory and a nonvolatile memory, the method comprising the steps of:
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operating the volatile memory with a normal mode; monitoring access requirements to the volatile memory and detecting an access frequency of the volatile memory; comparing a used space of the volatile memory and an available space of the nonvolatile memory when the access frequency of the volatile memory is smaller than a first set value; forwarding data stored in the volatile memory to the nonvolatile memory when the used space of the volatile memory is smaller than the available space of the nonvolatile memory; changing the volatile memory from the normal mode to a stop mode; monitoring access requirements to the nonvolatile memory and measuring a data transferring speed of the nonvolatile memory; returning the volatile memory from the stop mode to the normal mode when the data transferring speed of the nonvolatile memory is higher than a second set value; and forwarding part of data in the volatile memory to the nonvolatile memory when an available space of the volatile memory is smaller than a third set value, wherein the third set value is configured to be changed depending on temperature of the volatile memory; wherein the normal mode is a mode supplying a first power supply voltage to the volatile memory, and wherein the stop mode is a mode not supplying any power supply voltage to the volatile memory. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification