On-Chip RC Oscillator Frequency Trimming for Temperature Stability
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Solution Overview
Problem
Existing on-chip RC oscillators face limitations in accuracy due to temperature characteristics and process dispersion, particularly in high-frequency applications, where temperature calibration is challenging and affects the stability and reliability of clock signals in integrated circuit chips and communication interfaces.
Innovation Solution
An on-chip RC oscillator design incorporating a stabilized voltage supply module, an RC core oscillator module, a frequency sampling and conversion module, and a frequency trimming module, which generates a control signal with a suitable temperature coefficient and zero temperature coefficient current to calibrate and compensate for temperature changes, ensuring accurate clock frequency output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature calibration is performed using active devices and resistors, then temperature compensation is achieved, but process dispersion and electrical parameter dependence limit accuracy
Solution Approach 1:
The patent replaces the traditional mechanical/electrical calibration approach (using resistors and active devices) with a digital calibration system. The frequency calibration is achieved through digital signal processing and algorithmic compensation, eliminating the dependence on physical component tolerances and process dispersion.
Solution Approach 2:
The patent dynamically adjusts calibration parameters based on measured temperature and frequency deviations. By changing the calibration parameters digitally rather than through fixed physical components, the system achieves higher accuracy while maintaining temperature compensation.
2Reliability
If digital delay units are used for temperature compensation, then temperature coefficient adjustment is achieved, but digital logic delay time limits high-frequency performance
Solution Approach 1:
The patent replaces digital logic delay units with an analog temperature compensation mechanism that uses temperature-sensitive components to directly adjust the oscillator frequency. This substitution eliminates the speed limitations inherent in digital logic circuits while maintaining temperature compensation capability.
Solution Approach 2:
The patent introduces a temperature-sensitive capacitor or resistor as an intermediary element that directly couples the temperature compensation function to the oscillator circuit. This intermediary enables continuous analog adjustment without the discrete timing constraints of digital logic.
Data Source
AI summary
Disclosed are an on-chip RC oscillator, a chip, and a communication terminal. The on-chip RC oscillator comprises a stabilized voltage supply module, an RC core oscillator module, a frequency sampling and conversion module, and a frequency trimming module. By means of the frequency sampling and conversion module, the clock frequency of the oscillator is sampled and detected in real time, and the sampled clock frequency is converted into a voltage signal, and then analog-to-digital conversion is performed to obtain a corresponding digital code, so that when the clock frequency changes, the frequency trimming module circuit converts said digital code into a control signal; a voltage having a suitable temperature coefficient is outputted for the RC core oscillator module; also, a zero temperature coefficient current of a suitable magnitude is outputted for the RC core oscillator module, so as to precisely calibrate the clock frequency.