Complementary Logic Circuit Biasing for PVT and Timing Skew
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Solution Overview
Problem
Performance variations in semiconductor devices due to fabrication process variations, voltage, and temperature (PVT) lead to asymmetrical output waveforms, reduced current drive, and increased layout area, necessitating the development of self-correcting circuits with improved timing accuracy and reduced power consumption.
Innovation Solution
The implementation of a complementary logic circuit with separate variable power supplies for p-type and n-type transistors, coupled with a bias network and a feedforward configuration of inverters and buffers, which mitigates differences in switching times and slew rates, and reduces the impact of electrostatic discharge components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the p-type semiconductor device is made larger to compensate for reduced charge carrier mobility, then the current drive is improved, but the circuit area increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the width-to-length ratios of transistors based on detected performance variations. Specifically, the circuit measures actual PVT conditions and modifies transistor dimensions (W/L ratios) to optimize current drive without permanently increasing circuit area. This allows the p-type device to achieve adequate drive strength through adaptive parameter adjustment rather than fixed size increase.
2Reliability
If ESD components are coupled between power supplies and the complementary logic circuit to protect against electrostatic discharge, then reliability is improved, but the circuit area increases
Solution Approach 1:
The patent merges the ESD protection function with the existing power supply network by integrating protection mechanisms into the power distribution structure. Rather than adding separate ESD components that would increase area, the design incorporates protection functionality into the power supply paths, achieving reliability improvement without proportional area increase.
3Measurement precision
If separate variable power supplies are used for p-type and n-type transistors to mitigate switching time differences, then timing accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamics by using variable, adjustable power supplies for p-type and n-type transistors rather than fixed supplies. The power supply voltages can be dynamically tuned to compensate for timing skew and performance variations. This dynamic adjustment capability allows the system to achieve high timing accuracy while managing complexity through controlled adaptability rather than rigid fixed-parameter design.
4Productivity
If the degree of miniaturization increases to improve performance, then productivity is improved, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent applies self-service by implementing circuits that automatically detect and compensate for their own performance variations. The system measures actual PVT conditions and self-adjusts transistor parameters to maintain optimal performance. This self-correcting capability allows the circuit to tolerate fabrication variations without requiring extremely tight manufacturing precision, enabling continued miniaturization while maintaining performance.
Data Source
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AI summary
Systems and methods for circuits that self correct errors due to variations in fabrication processes, voltages, and temperature (PVT), as well as input timing errors. In an exemplary embodiment, a method for improving output signal (410) quality in a complementary logic circuit (400) is provided. An n-type transistor in the complementary logic circuit is digitally enabled or biased (Control B, Control D) with a first variable power supply (Vss). A p-type transistor in the complementary logic circuit is digitally enabled or biased (Control A, Control C) with a second variable power supply (Vdd), providing a voltage different from that of the first variable power supply, to mitigate a difference in the switching times between the p-type transistor (435) and the n-type transistor (440).