Voltage-Restricted Oscillator Circuit for Full-Swing Low-Power Output
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Solution Overview
Problem
Existing oscillator circuits for semiconductor integrated circuits face challenges in achieving full swing with low power consumption, as they require amplification circuits that increase power consumption and have limited oscillation amplitude, especially at high frequencies.
Innovation Solution
The proposed oscillation circuit includes an oscillation core block, a voltage restriction block, and a differential output block, utilizing p-channel and n-channel MOS transistors to maintain a constant oscillation amplitude and achieve full swing between the power supply voltage and ground voltage without additional current supply, using a simple circuit structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an amplification circuit is added to achieve full swing, then the oscillation amplitude is improved, but the power consumption increases
Solution Approach 1:
The patent extracts the voltage restriction function from a separate amplification circuit and integrates it directly into the oscillation core block. By taking out the essential voltage control function and embedding it within the existing circuit structure, the patent achieves full swing capability without adding external amplification stages, thereby avoiding the associated power consumption increase.
Solution Approach 2:
The voltage restriction block performs multiple functions: it restricts the oscillation voltage to achieve full swing, maintains stable oscillation amplitude, and controls the operating point of the oscillation transistors. This multi-functionality eliminates the need for separate amplification circuits, reducing overall power consumption while achieving the desired oscillation characteristics.
2Speed
If the oscillation frequency is increased, then the operation speed is improved, but the oscillation amplitude decreases due to parasitic capacitance
Solution Approach 1:
The voltage restriction block provides negative feedback to the oscillation core block by restricting the oscillation voltage. This feedback mechanism compensates for the amplitude reduction caused by parasitic capacitance at high frequencies, maintaining stable oscillation amplitude across a wide frequency range including high-frequency operation.
Solution Approach 2:
The patent changes the operating parameters of the oscillation transistors through the voltage restriction block, which controls the gate-source voltage to maintain optimal operating conditions. This parameter control compensates for frequency-dependent effects like parasitic capacitance, allowing high-frequency operation with maintained amplitude.
3Device complexity
If a self-biased CMOS inverter is used, then the circuit scale is reduced, but the oscillation amplitude becomes small requiring additional amplification
Solution Approach 1:
The patent merges the voltage restriction function with the oscillation core block, combining what would traditionally be separate circuits into a unified structure. This integration maintains the compactness of the self-biased CMOS inverter while adding full swing capability through the embedded voltage restriction block, avoiding the need for additional external amplification circuits.
Data Source
AI summary
An oscillator circuit having a relatively simple circuit structure while enabling full swing with low power consumption includes an oscillation core block, a voltage restriction block, and a differential output block. Drain terminals of first and second transistors are each connected to the voltage restriction block. The voltage restriction block restricts the amplitude of an oscillation signal to a reference voltage. Source terminals of third and fourth transistors are connected to drain terminals of fifth and sixth transistors, and source terminals of seventh and eighth transistors are connected to drain terminals of ninth and tenth transistors. This supplies the differential output block with current generated by the amplitude restriction. The differential output block converts the current into drive voltage to ground voltage to perform full swing.