Software-Controlled IO Isolation in Integrated Circuits

The patent divides the IO isolation control into individual per-IO-cell units rather than using a single common control mechanism. Each IO cell has its own isolation latch and control logic, allowing independent control of each IO cell's isolation state. This segmentation enables selective isolation of only those IO cells that need to be isolated during sleep mode, rather than isolating all IO cells simultaneously, thereby reducing unnecessary power consumption while maintaining flexibility in control.

The patent applies different isolation states to different IO cells based on their specific requirements. Each IO cell can be independently configured to be isolated or non-isolated during sleep mode depending on whether it needs to maintain stability and detectability. This local quality approach allows the system to isolate only those IO cells that do not require continuous operation, while keeping critical IO cells connected and stable, thereby reducing overall leakage current without compromising necessary IO cell reliability.

The patent combines the control logic for multiple IO isolation circuits into a unified structure where each IO cell shares common control signals and timing mechanisms from the always active area. While each IO cell has its own isolation latch for independent control capability, the control signals, state machines, and timing logic are merged and shared across all IO cells. This merging approach provides the flexibility of individual control when needed while avoiding the complexity of completely separate control circuits for each IO cell.