CMOS Skew Trigger Circuit for P/N Device Drift Compensation
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Solution Overview
Problem
CMOS circuits face issues due to drift in the absolute or relative strength of P-devices and N-devices caused by manufacturing process variations and phenomena like NBTI, PBTI, and HCI, leading to inefficiencies in handling timing, drive strength, and rise/fall times, which existing solutions address with costly measures such as longer timing intervals and increased drive strength.
Innovation Solution
A circuit skew compensation trigger system that monitors the relative strength of P-devices and N-devices in real time using a voltage divider technique, triggering a compensator when the difference exceeds a threshold, adjusting timing or compensating for drift through mechanisms like switching in additional devices or altering voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If longer timing intervals and larger base drive strength are provided to handle drift, then circuit reliability is improved, but circuit complexity and overhead costs increase
Solution Approach 1:
The patent applies preliminary action by proactively detecting drift in P-device or N-device strength before it causes circuit failure. The sensor circuit continuously monitors device characteristics and triggers compensation mechanisms in advance, allowing the circuit to maintain reliability without requiring oversized components or excessive timing margins that would increase complexity.
Solution Approach 2:
The patent implements feedback through a closed-loop system where sensor circuits detect drift conditions, trigger circuits generate compensation signals, and compensator circuits adjust device characteristics accordingly. This feedback mechanism enables the circuit to automatically correct drift issues, maintaining reliability without the need for static design margins that would increase complexity and overhead.
2Reliability
If longer timing intervals are used to accommodate drift, then circuit reliability is improved, but productivity decreases
Solution Approach 1:
The patent applies dynamics by making timing intervals adaptive rather than static. The sensor circuit detects actual drift conditions in real-time and dynamically adjusts timing parameters through trigger circuits and compensators. This allows the circuit to operate at maximum speed when devices are within specifications while automatically extending timing only when drift is detected, thereby maintaining both high productivity and reliability.
3Reliability
If larger base drive strength is provided to handle drift, then circuit reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting device characteristics such as drive strength based on detected drift conditions. The sensor circuit monitors device parameters and the compensator circuits modify them in response to drift, allowing the circuit to use minimum necessary power during normal operation while maintaining reliability through targeted parameter adjustments only when needed.
Data Source
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AI summary
A circuit skew compensation trigger system comprises a voltage divider including a P-transistor and an N-transistor and a center node in the voltage divider pulled to a first level. The circuit skew compensation trigger system further comprising a trigger to activate when a skew between the P-transistor and the N-transistor is above a threshold. The trigger to initiate a compensator to adjust for the skew.