Self-Biasing Inverter Clock Conditioning for Duty Cycle Correction
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Solution Overview
Problem
Existing clock generation circuits in IC devices face challenges in managing power consumption and reliability due to variations in clock signal phase relationships, leading to errors in data transmission and reception, particularly in high-speed serial communication interfaces.
Innovation Solution
A programmable clock conditioning circuit with a duty cycle correction circuit and a self-biasing inverter, coupled with a variable capacitor, is used to adjust capacitance and transition times of clock signals, reducing the need for complex calibration and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple increased frequency clock signals are used to control SERDES operation, then timing control performance is improved, but power consumption increases
Solution Approach 1:
The patent uses a variable capacitor with programmable capacitance values to adjust the phase shift of clock signals. By changing the capacitance parameter, the circuit can achieve different phase relationships without increasing frequency or complexity, thereby maintaining timing control performance while reducing power consumption compared to using multiple high-frequency clock signals.
Solution Approach 2:
The patent introduces a clock conditioning circuit with a variable capacitor as an intermediary element between the clock source and the SERDES components. This intermediary allows precise control of phase relationships through capacitance adjustment, avoiding the need for multiple independent high-frequency clock sources, thus reducing overall power consumption while maintaining timing accuracy.
2Measurement precision
If multiple clock signals with different phases are used for SERDES operation, then timing accuracy is improved, but phase relationship variations cause errors
Solution Approach 1:
The patent incorporates a feedback mechanism where the phase relationship of clock signals is monitored and adjusted through the variable capacitor. The programmable capacitance allows dynamic compensation for phase variations, ensuring that timing accuracy is maintained and phase relationship drift is corrected, thereby improving data transmission reliability.
Solution Approach 2:
The patent uses a dynamically adjustable variable capacitor that can be reconfigured based on operating conditions. This dynamic adjustment capability allows the circuit to adapt to phase variations in real-time, maintaining accurate timing relationships between clock signals and preventing errors caused by phase drift, thus improving reliability while preserving timing accuracy.
3Measurement precision
If complex calibration circuits are used to correct duty cycle distortion, then clock signal accuracy is improved, but circuit complexity and die area increase
Solution Approach 1:
The patent achieves duty cycle distortion correction by programmably changing the capacitance value of the variable capacitor. This single parameter adjustment (capacitance) replaces what would traditionally require complex multi-element calibration circuits, reducing die area and circuit complexity while maintaining clock signal accuracy.
Solution Approach 2:
The variable capacitor serves multiple functions: it adjusts phase relationships between clock signals, corrects duty cycle distortion, and enables programmable timing control. This multi-functionality eliminates the need for separate dedicated calibration circuits, thereby reducing overall circuit complexity and die area while achieving accurate clock signal conditioning.
4Measurement precision
If traditional duty cycle correction circuits are used, then duty cycle distortion is corrected, but power consumption and die area increase
Solution Approach 1:
The patent corrects duty cycle distortion by programmably adjusting the capacitance of the variable capacitor, which modifies the charging/discharging time constants of the clock signal edges. This parameter-based correction approach is more power-efficient than traditional active correction circuits, as it uses passive capacitance adjustment rather than continuous active switching, thereby reducing power consumption while achieving accurate duty cycle correction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively corrects duty cycle distortion and skew in clock signals, enhancing data transmission accuracy while reducing die area and power consumption, thus improving the performance of SERDES circuits in IC devices.
Implementation Method 1
A variable capacitor is coupled to the first input capacitor. A capacitance of the variable capacitor is programmable by a capacitance control signal
Implementation Method 2
a first self-biasing inverter that has an input coupled to the first input capacitor
Data Source
AI summary
A clock conditioning circuit includes a duty cycle correction circuit. The duty cycle correction circuit has a first input capacitor, a first self-biasing inverter and a variable capacitor. The first self-biasing inverter has an input coupled to the first input capacitor. The variable capacitor may be coupled to the first input capacitor. The variable capacitor may be configured to receive a first clock signal. A capacitance of the variable capacitor may be programmable by a capacitance control signal.