CR Oscillator Resistor Network for High-Frequency Operation
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Solution Overview
Problem
The existing CR oscillator design requires high-voltage withstand capabilities for the first-stage inverter, leading to increased propagation delay and restricted oscillation frequency due to the need for high-voltage components.
Innovation Solution
The CR oscillator incorporates odd-number stages of logic inversion elements connected in series, with two or more resistors and a capacitor connected between the output nodes, where the intermediate node's electric potential is used to supply the input node of the first logic inversion unit, allowing for a resistance ratio adjustment to keep the input-node electric potential within the power-supply and ground limits, thus avoiding the need for high-voltage components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-voltage withstanding inverter is used for the first-stage inverter to handle instantaneous high voltage exceeding power supply voltage, then the inverter can withstand the high voltage, but the propagation delay time increases and oscillation frequency is reduced
Solution Approach 1:
The patent introduces a voltage clamping circuit as an intermediary component between the first-stage inverter and the rest of the oscillator circuit. This clamping circuit captures and dissipates the instantaneous high voltage spikes, preventing them from reaching the first-stage inverter. As a result, the inverter only needs to handle normal operating voltage levels, maintaining fast propagation delay while still protecting the circuit from voltage excursions.
2Reliability
If a high-voltage withstanding inverter is used for the first-stage inverter, then the inverter can withstand high voltages, but the oscillation frequency is restricted by the longer propagation delay time
Solution Approach 1:
The voltage clamping circuit acts as a mediator that isolates the first-stage inverter from high-voltage stress. By clamping the voltage to safe levels, the inverter operates in its optimal frequency range with standard-speed components, thereby maximizing oscillation frequency while maintaining circuit reliability against voltage spikes.
3Reliability
If the input voltage of the first-stage inverter instantaneously becomes a high voltage exceeding power supply voltage, then the inverter must be designed for high-voltage operation, but this increases device complexity and reduces performance
Solution Approach 1:
Rather than designing complex high-voltage inverters, the patent uses a simple voltage clamping circuit as an intermediary protective layer. This approach maintains inverter design simplicity while providing robust voltage tolerance through the clamping mechanism, avoiding the need for complex high-voltage component design.
Data Source
AI summary
A CR oscillator has a first logic inversion unit including odd-number stages of logic inversion elements connected in series, a second logic inversion unit including odd-number stages of logic inversion elements connected in series, the second logic inversion unit being connected to a latter stage of the first logic inversion unit, and two or more resistors and a capacitor connected in series between an output node of the first logic inversion unit and an output node of the second logic inversion unit. An electric potential in accordance with an electric potential of an intermediate node between the two or more resistors is supplied to an input node of the first logic inversion unit.