Dynamic voltage frequency scaling method and apparatus

1. A system-on chip (SOC) comprising:

a central processing unit (CPU) to operate a dynamic voltage frequency scaling (DVFS) control unit,

the DVFS control unit comprising:

a SOC load calculating unit to calculate a SOC load based on at least one element of the SOC;

a DVFS table selecting unit for determining a scenario of a CPU operation based on a result of analyzing a pattern of the SOC load or according to an external input, and determining a DVFS table suitable for the scenario; and

a DVFS calculating unit for determining a DVFS operation corresponding to the SOC load and a current operating frequency, based on the determined DVFS table among a plurality of DVFS tables,

wherein each of the plurality of DVFS tables is configured to comprise up-thresholds and down-thresholds corresponding to operating frequencies of the CPU, and

the up-thresholds and the down-thresholds are calculated based on a plurality of OFSL (Operating Frequency to SOC Load) ratio values corresponding to the ratio between each of the plurality of operating frequencies and the SOC load.

2. The SOC of claim 1 , wherein the DVFS control unit further comprises a DVFS table storing unit for storing the plurality of DVFS tables and providing the plurality of DVFS tables to the DVFS table selecting unit.

3. The SOC of claim 1 ,

wherein in some of the plurality of DVFS tables, ratios between the operating frequencies and the up-thresholds vary according to the operating frequencies.

4. The SOC of claim 1 ,

wherein in some of the plurality of DVFS tables, ratios between the operating frequencies and the down-thresholds vary according to the operating frequencies.

5. The SOC of claim 1 , wherein the external input comprises application execution information and a CPU control signal.

6. The SOC of claim 1 , wherein the DVFS table selecting unit determines a DVFS table suitable for the scenario by selecting at least one of the plurality of DVFS tables.

7. The SOC of claim 1 , wherein the DVFS operation comprises a first policy and a second policy,

wherein the first policy increases the operating frequency of the CPU and an operating voltage of the SOC, and

the second policy decreases the operating frequency of the CPU and the operating voltage of the SOC.

8. The SOC of claim 1 , further comprising:

a performance monitoring unit for measuring the memory usage of at least one of the elements of the SOC and transmitting information regarding the memory usage to the DVFS control unit; and

a clock management unit for changing an operating frequency of the CPU to perform the DVFS operation, under control of the DVFS control unit.

9. An electronic system comprising

the SOC of claim 1 ; and

a power management integrated circuit for generating an operating voltage of the SOC and applying the operating voltage to the SOC so as to perform a dynamic voltage frequency scaling (DVFS) operation.

10. A dynamic voltage frequency scaling (DVFS) controlling method comprising:

calculating a system-on chip (SOC) load on at least one of elements of a SOC;

determining a scenario of a central processing unit (CPU), based on analyzing a pattern of the SOC load or according to an external input;

determining whether a current DVFS table is to be replaced with another DVFS table depending on the scenario; and

determining a DVFS operation corresponding to the SOC load and an operating frequency of the CPU, based on the current DVFS table or a replaced DVFS table,

wherein each of the plurality of DVFS tables is configured to comprise up-thresholds and down-thresholds corresponding to operating frequencies of the CPU, and

the up-thresholds and the down-thresholds are calculated based on a plurality of OFSL (Operating Frequency to SOC Load) ratio values corresponding to the ratio between each of the plurality of operating frequencies and the SOC load.

11. The DVFS controlling method of claim 10 , if it is determined that the current DVFS table is to be replaced with another DVFS table, further comprising determining a DVFS table suitable for the scenario by selecting at least one of a plurality of DVFS tables.

12. The DVFS controlling method of claim 11 ,

and in some of the plurality of DVFS tables, ratios between the operating frequencies and the up-thresholds vary according to the operating frequencies.

13. The DVFS controlling method of claim 11 ,

wherein in some of the plurality of DVFS tables, ratios between the operating frequencies and the down-thresholds vary according to the operating frequencies.

14. The DVFS controlling method of claim 10 , wherein the external input comprises application execution information and a CPU control signal.

15. The DVFS controlling method of claim 10 , wherein the DVFS operation comprises a first policy and a second policy,

wherein the first policy instructs to increase an operating frequency of CPU and an operating voltage of the SOC, and

the second policy instructs to decrease the operating frequency of the CPU and the operating voltage of the SOC.

16. A system on a chip (SOC), comprising:

a multi-core processor;

system elements; and

a dynamic voltage frequency scaling (DVFS) controller, the DVFS controller to allot greater or lesser power to the SOC depending upon the SOC's mode of operation and current operating frequency, wherein the DVFS controller is configured to determine the mode of operation by analyzing system activity and to allot greater or lesser power according to one of a plurality of DVFS tables selected on the basis of a load pattern or an external input, wherein the external input comprises application execution information and/or a CPU control signal and each of the plurality of DVFS tables is configured to comprise up-thresholds and down-thresholds corresponding to operating frequencies of the CPU, and

the up-thresholds and the down-thresholds are calculated based on a plurality of OFSL (Operating Frequency to SOC Load) ratio values corresponding to the ratio between each of the plurality of operating frequencies and the SOC load.

17. The SOC of claim 16 , wherein the DFVS controller is configured to allot greater or lesser power by adjusting an operating frequency.

18. The SOC of claim 16 , wherein the DVFS controller is configured to allot greater or lesser power by adjusting an operating voltage.

19. The SOC of claim 16 , wherein the DVFS controller is configured to allot greater or lesser power by adjusting an operating voltage and frequency for a plurality of the cores of the multicore processor.

20. An electronic system including the SOC of claim 16 .