Integrated Circuit Mode Switching via Internal Memory Copy
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Solution Overview
Problem
Power management in integrated circuits, particularly in mobile devices, is complex due to the need to switch between different clock frequencies and supply voltages, often requiring resetting to ensure correct operation, which can lead to unreliable mode changes and potential failures.
Innovation Solution
An integrated circuit with a processor, internal memory, and a memory controller that uses switch code to reliably switch between modes by copying switch code from external memory into internal memory, entering self-refresh mode to preserve data, and reinitializing the memory controller, allowing mode changes without resetting the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the integrated circuit resets to switch between modes with different clock frequencies and supply voltages, then the integrated circuit can operate correctly at the new operating point, but the mode switching becomes unreliable and may cause failures
Solution Approach 1:
The patent applies preliminary action by executing switch code before the actual mode transition. The switch code is copied from external memory to internal memory in advance, and the external memory is placed in self-refresh mode before the operating point changes. This ensures that the memory controller is reinitialized and ready before the new mode begins, preventing failures during mode switching without requiring a full system reset.
2Use of energy by moving object
If the integrated circuit switches between modes with different operating points, then power management and power consumption are improved, but the complexity of switching between modes increases
Solution Approach 1:
The patent uses copying by duplicating the switch code from external memory into internal memory. This allows the processor to execute the mode switching sequence from the faster internal memory rather than repeatedly accessing external memory, reducing the complexity of the switching mechanism while maintaining power management benefits. The copied switch code contains all necessary instructions for transitioning between operating points.
Solution Approach 2:
The patent introduces an intermediary approach by using self-refresh mode as a intermediate state between different operating modes. The external memory enters self-refresh mode to preserve contents during the transition, acting as a buffer that allows the memory controller to reinitialize without losing data. This intermediary state simplifies the switching process while maintaining data integrity.
3Loss of information
If the external memory enters self-refresh mode to preserve contents during mode switching, then data retention is maintained, but the memory controller must be reinitialized after stabilization
Solution Approach 1:
The patent applies preliminary action by entering self-refresh mode before the operating point changes and reinitializing the memory controller after stabilization. This timing sequence ensures that data is preserved during the transition while the memory controller is reinitialized in a controlled manner. The switch code coordinates these operations to minimize the reinitialization time while maintaining data retention.
Data Source
AI summary
In one embodiment, an integrated circuit includes a processor, an internal memory, and a memory controller coupled to an external memory. The integrated circuit may support two or more modes of operation, with different operating points. To switch from one operating point to another, code executed by the processor may copy switch code from the external memory into the internal memory, and may jump to the switch code. Executing out of the internal memory, the switch code may communicate with the memory controller to cause the external memory to enter into self-refresh mode. The operating point may be altered, and the switch code may reinitialize the memory controller after the integrated circuit has stabilized at the new operating point. After the memory controller's physical interface circuit has relocked, the external memory may exit self-refresh mode.