RC Oscillator Circuit Using Miller Capacitance for Low Frequency
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Solution Overview
Problem
Existing 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 does not increase power consumption and avoids specialized fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a high RC value is used to achieve low operation frequency, then the oscillation frequency is reduced, but the capacitor size increases
Solution Approach 1:
The patent changes the effective capacitance parameter by introducing a negative amplifier configuration. The capacitor C1 is connected between the input and output of an inverter configured as a negative amplifier, which multiplies the effective capacitance by (1 - A) where A is the voltage gain. This allows achieving large effective capacitance values without physically enlarging the capacitor, thus reducing capacitor size while maintaining low operation frequency.
Solution Approach 2:
The inverter configured as a negative amplifier acts as an intermediary element that transforms the relationship between the physical capacitor and the oscillation frequency. Instead of directly increasing capacitor size to achieve low frequency, the negative amplifier mediates by providing a gain-based multiplication effect on the capacitance, decoupling the physical size from the effective capacitance value.
2Quantity of substance
If advanced capacitor manufacturing technology is used to achieve high-density capacitors, then capacitor density increases, but manufacturing complexity and costs increase
Solution Approach 1:
Rather than relying on advanced manufacturing to increase physical capacitance density, the patent changes the effective capacitance parameter through circuit configuration. The negative amplifier configuration provides an electrical multiplication effect on the capacitance, achieving high effective capacitance values using standard manufacturing processes and components, thereby avoiding increased manufacturing complexity.
Solution Approach 2:
The patent creates an electrical 'copy' or virtual representation of increased capacitance through the negative amplifier's gain effect. Instead of physically creating high-density capacitors through complex manufacturing, the circuit generates an equivalent electrical effect that mimics the behavior of large capacitors, achieving the same functional result through a simpler, more cost-effective approach.
3Ease of manufacture
If standard capacitor sizes are used in RC oscillators, then manufacturing costs are reduced, but achieving low operation frequencies requires larger capacitor sizes
Solution Approach 1:
The patent resolves this contradiction by changing the effective capacitance parameter through the negative amplifier configuration. Standard-sized capacitors can be used (maintaining low manufacturing cost), while the negative amplifier multiplies the effective capacitance to achieve the large RC time constant needed for low operation frequencies. This decouples the relationship between physical capacitor size and effective capacitance value.
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 large capacitance value in a smaller capacitor size, reducing the overall size and costs associated with achieving low operation frequencies.
Implementation Method 1
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
Data Source
AI summary
An apparatus includes a first inverter having an input terminal and an output terminal, a first capacitive device connected between the input terminal and the output terminal of the first inverter, and a resistor network 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.