Semiconductor device and semiconductor device control method
Disclosed is a semiconductor device in which an internal voltage fluctuation when a current jump occurs is restrained. The semiconductor device includes a plurality of blocks, each of which performs a given operation, and a current jump control circuit. The current jump control circuit monitors control signals in each of the blocks and calculates predicted values of consumption current of the blocks, based on results of monitoring at different timings, thereby controlling a fluctuation of consumption current of the blocks. The current jump control circuit controls operation of a subset or all of the blocks, if an increase of a predicted value of consumption current of the blocks is larger than a first value or a decrease of the predicted value is larger than a second value.
1. A semiconductor device comprising:
a plurality of blocks, each of which performs a given operation; and
a control circuit which monitors control signals in each of the blocks and calculates a predicted value of consumption current of the blocks, based on results of monitoring at different timings, thereby controlling a fluctuation of consumption current of the blocks,
wherein if an increase of a predicted value of consumption current of the blocks is larger than a first value, the control circuit controls a subset or all of the blocks to decrease consumption current, and
wherein if a decrease of the predicted value of consumption current of the blocks is larger than a second value, the control circuit controls a subset or all of the blocks to increase consumption current.
2. The semiconductor device according to claim 1 ,
wherein the control circuit calculates a first predicted value of consumption current of the blocks,
wherein the control circuit calculates a second predicted value of consumption current of the blocks after calculating the first predicted value of consumption current of the blocks,
wherein if a value obtained by subtracting the first predicted value of consumption current of the blocks from the second predicted value of consumption current of the blocks is larger than the first value, the control circuit deactivates a subset or all of the blocks or decreases a operating frequency of a subset or all of the blocks, and
wherein if a value obtained by subtracting the second predicted value of consumption current of the blocks from the first predicted value of consumption current of the blocks is larger than the second value, the control circuit activates a subset or all of the blocks to perform a given operation or increases a operating frequency of a subset or all of the blocks.
3. The semiconductor device according to claim 2 , wherein each of the first and second predicted values of consumption current of the blocks is a predicted value of consumption current of the blocks for a period including one or more clock cycles.
4. The semiconductor device according to claim 3 ,
wherein one of the blocks is a memory block, and
wherein one of the control signals is an enable signal for the memory block.
5. The semiconductor device according to claim 4 , wherein the given operation is a dummy read of the memory block.
6. The semiconductor device according to claim 3 , wherein at least one of the blocks comprises a dummy circuit which operates when the given operation is performed.
7. The semiconductor device according to claim 1 , wherein the control circuit maintains an operating state of the subset or all of the blocks for a given period of time, after forcedly controlling operation of the subset or all of the blocks.
8. The semiconductor device according to claim 7 , wherein the control circuit monitors a power supply voltage, after maintaining the operating state of the subset or all of the blocks for the given period of time, and cancels the forced control exerted on operation of the subset or all of the blocks, if the power supply voltage remains within a given range for the given period of time.
9. The semiconductor device according to claim 1 , wherein the control circuit comprises a storage unit in which parameters are stored for use in calculating the predicted values of consumption current of the blocks from the results of monitoring.
10. The semiconductor device according to claim 9 , wherein parameters for the control circuit to control operation of the subset or all of the blocks are stored in the storage unit.
11. The semiconductor device according to claim 10 ,
wherein the parameters stored in the storage unit can be updated,
wherein a control is exerted on operation of the subset or all of the blocks, if it has been detected that a predicted value of consumption current of the blocks calculated using the parameters set in the storage unit deviates from a given current range, and
wherein the control circuit monitors a power supply voltage, retains used parameters as the parameters in the storage unit, if a fluctuation of the monitored power supply voltage falls within a given voltage range, and changes parameter values set in the storage unit, if the fluctuation of the power supply voltage is out of the given voltage range.