State Machine Patch Circuit for Low-Cost IC State Corrections
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Solution Overview
Problem
The high cost of remanufacturing integrated circuits (ICs) due to poorly designed state machines, where the number of logic gates required for modifications exceeds the number of spare cells, making it impractical to correct erroneous state switching or add new states without significant re-manufacturing efforts.
Innovation Solution
A state machine circuit with a state patch circuit that generates patched predicted states and output values based on current and input signals, allowing for flexible correction of erroneous designs and addition of new states through firmware or software updates, utilizing a patch register to store modification criteria and generate selection signals for the first and second selection circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If state machine modifications are required due to poor design, then the state switching can be corrected, but the cost for remanufacturing the IC becomes extremely high when the number of logic gates required for modifications exceeds the number of spare cells
Solution Approach 1:
The patent applies preliminary action by pre-configuring spare cells and state patch circuits into the IC before final assembly. These spare resources are prepared in advance specifically for potential state machine modifications, allowing corrections without expensive remanufacturing. The state patch circuit is pre-integrated with selection circuits that can activate alternative state transitions when modification needs are detected.
Solution Approach 2:
The patent utilizes parameter changes by modifying the state transition parameters through firmware or configuration data rather than physically changing the hardware logic gates. The state patch circuit alters the effective state transition table by selecting different next states based on configuration signals, enabling design corrections through parameter adjustment instead of physical remanufacturing.
2Adaptability or versatility
If the number of logic gates required for modifications exceeds the number of spare cells, then state machine corrections become impractical, but the patent introduces a state patch circuit to enable corrections within existing IC structure
Solution Approach 1:
The state patch circuit serves multiple functions: it can correct erroneous state transitions, add new states, modify transition conditions, and preserve original functionality when not needed. The same circuit structure handles various types of state machine modifications through configurable selection logic, making the IC adaptable to different correction scenarios without requiring separate solutions for each modification type.
Solution Approach 2:
The state patch circuit acts as an intermediary layer between the original logic circuit and the state register. Instead of directly modifying the complex logic gates, the patch circuit intercepts the state transition signals, applies corrections through selection logic, and forwards the modified signals to the state register. This intermediary approach enables modifications without directly altering the core IC structure.
3Reliability
If state design needs to be altered by remanufacturing the IC, then correct state switching is achieved, but the manufacturing cost and time are significantly increased
Solution Approach 1:
The patent creates a virtual copy of the state machine functionality through the state patch circuit, which replicates and modifies the state transition behavior without physically copying or remanufacturing the entire IC. The selection circuits generate alternative state transition paths that copy the intended correct behavior, allowing rapid implementation of design corrections.
Solution Approach 2:
The state machine becomes dynamic and reconfigurable through the state patch circuit, which can alter state transition behavior in real-time based on configuration signals. Unlike static remanufactured ICs, this approach allows the state machine to adapt its transition logic dynamically through firmware updates or configuration changes, enabling rapid corrections without physical remanufacturing cycles.
Data Source
AI summary
A state machine circuit switching between multiple states is provided. The state machine circuit has: a state patch circuit for generating a patched predicted state value, a patched output value, and a selection signal according to a current state value and at least one of a second input signal, a predicted state value, and an output value of the state machine circuit; a first selection circuit for outputting the patched predicted state or the predicted state to a register according to the selection signal; and a second selection circuit for outputting the patched output value or the output value according to the selection signal, wherein the predicted state value and the output value are generated according to a first input signal and the current state value of the state machine circuit, and the predicted state value and the output value are not generated according to the second input signal.