Phase Interpolation Circuit Control for Low-Jitter MOSFET Bias Stability
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Solution Overview
Problem
The accuracy of phase interpolation in semiconductor devices is deteriorated due to fluctuations in the bias voltage of MOSFETs, and traditional methods to stabilize this voltage, such as using a large stabilizing capacitor, increase the circuit area and reduce high-speed operation capabilities, leading to increased jitter.
Innovation Solution
A semiconductor device with a phase interpolation circuit that includes an N-bit current digital-analog conversion circuit, a switch circuit, a capacitive element, an inverter, and a control logic circuit. The control logic circuit detects the end of the phase interpolation operation and outputs control signals to turn off the current digital-analog conversion circuit and inverter, reducing bias voltage fluctuations and allowing for high-speed operation without increasing circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a large stabilizing capacitor is connected to the gate of the MOSFET to suppress bias voltage fluctuation, then the bias voltage stability is improved, but the circuit area increases and the time constant increases making high-speed operation difficult
Solution Approach 1:
The patent extracts the stabilizing capacitor from the traditional configuration and replaces it with a control logic circuit that detects the end of phase interpolation operation and turns off the current digital-analog conversion circuit. This removes the need for a large physical capacitor while maintaining voltage stability through active control.
Solution Approach 2:
The patent implements a feedback mechanism where the control logic circuit monitors the output of the inverter to detect when phase interpolation operation ends, and based on this feedback, controls the switching of the current digital-analog conversion circuit to maintain bias voltage stability without requiring a large capacitor.
2Stability of the object's composition
If a large stabilizing capacitor is connected to the gate of the MOSFET to suppress bias voltage fluctuation, then the bias voltage stability is improved, but the time constant increases making high-speed operation difficult and jitter increases
Solution Approach 1:
The patent removes the large stabilizing capacitor from the circuit and replaces its stabilizing function with an active control mechanism using the control logic circuit and switching elements, enabling high-speed operation without the time constant limitation imposed by large capacitors.
Solution Approach 2:
The patent employs periodic switching action through the control logic circuit that turns off the current digital-analog conversion circuit at appropriate moments (when phase interpolation ends), providing intermittent stabilization that maintains voltage stability without requiring continuous large capacitance, thus enabling high-speed operation.
3Speed
If the current digital-analog conversion circuit is kept on continuously to maintain operation, then the circuit can respond quickly, but the bias voltage fluctuates and accuracy deteriorates
Solution Approach 1:
The patent uses periodic switching control where the current digital-analog conversion circuit is turned off when phase interpolation operation ends, as detected by the control logic circuit. This periodic on-off operation maintains accuracy during critical phases while enabling quick response when needed, avoiding continuous operation that would cause voltage fluctuation.
Solution Approach 2:
The control logic circuit automatically detects the end of phase interpolation operation and autonomously controls the switching of the current digital-analog conversion circuit without external intervention. This self-service mechanism ensures the circuit operates at high speed when needed while maintaining accuracy by turning off at appropriate moments.
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 achieves high-accuracy and high-resolution phase interpolation with a small circuit area, enabling high-speed operation while minimizing jitter, thus addressing the limitations of traditional stabilization methods.
Implementation Method 1
a capacitive element
Data Source
AI summary
A semiconductor device includes a phase interpolation circuit including an N-bit current digital-analog conversion circuit, a switch circuit, a capacitive element, an inverter, and a control logic circuit. The control logic circuit detects an end of a phase interpolation operation by using an output result of the inverter and outputs a first control signal for turning off the current digital-analog conversion circuit. Also, the control logic circuit detects the end of the phase interpolation operation by using the output result of the inverter and outputs a second control signal for turning off the inverter.