Negative Amplifier Oscillator for Low Frequency
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Solution Overview
Problem
Existing semiconductor oscillators face challenges in achieving low operation frequencies with large RC values, leading to increased size and costs, while advanced capacitor manufacturing technologies require complex processes and higher costs.
Innovation Solution
A resistor-capacitor oscillator design utilizing a capacitor with enlarged effective capacitance through a negative amplifier configuration, which enhances capacitance without increasing power consumption or requiring specialized fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a large RC value is used to achieve low operation frequency, then the oscillation frequency is reduced, but the capacitor size and device area increase
Solution Approach 1:
The patent changes the effective capacitance parameter by introducing a negative amplifier configuration. The effective capacitance is transformed from the physical capacitor value to an amplified value (C_effective = C_physical * (1 + A)), where A is the amplifier gain. This allows achieving large RC time constants with small physical capacitor sizes, resolving the contradiction between low frequency operation and small device area
Solution Approach 2:
The negative amplifier acts as an intermediary element between the physical capacitor and the oscillator circuit. It mediates the capacitance value by providing gain amplification, allowing the physical capacitor to be much smaller than what would traditionally be required for low-frequency operation while maintaining the necessary RC time constant
2Quantity of substance
If high-value capacitors are manufactured using advanced semiconductor technology, then capacitor density increases, but manufacturing complexity and costs increase
Solution Approach 1:
Instead of manufacturing high-value capacitors directly using complex semiconductor processes, the patent creates a functional copy or equivalent of large capacitance through the negative amplifier circuit. The amplifier circuit replicates the effect of a large capacitor without requiring the physical fabrication of a large-capacitance device, thereby avoiding complex manufacturing procedures
Solution Approach 2:
The patent substitutes the physical capacitor manufacturing approach with an electronic circuit approach. Rather than relying on semiconductor fabrication processes to create high-value capacitors, the solution uses an operational amplifier-based negative impedance converter to synthesize the required capacitance, replacing mechanical/fabrication complexity with electronic circuitry
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 design achieves a significant reduction in capacitor size and maintains performance, allowing for lower operation frequencies with reduced costs compared to conventional oscillators.
Implementation Method 1
the first inverter is configured as a negative amplifier. The effective capacitance of the first capacitive device is equal to (A+2) times a capacitance of the first capacitive device, wherein A is a voltage gain of the negative amplifier
Data Source
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AI summary
An apparatus includes an odd number of inverter stages connected in a ring configuration, the inverter stages comprising a first inverter (702; 802; 902; 1002) having an input terminal and an output terminal, a first capacitive device (C1) connected between the input terminal and the output terminal of the first inverter, and a resistor network (R1) coupled to the first capacitive device, wherein the first inverter is configured as a negative amplifier, and the first capacitive device and the resistor network are configured to determine a frequency of an oscillator.