Calibrated Frequency Generator IC for Multi-Clock Output
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Solution Overview
Problem
Existing electronic systems rely on multiple quartz crystals for frequency generation, which are large, power-consuming, and introduce phase noise, while semiconductor-based solutions like phase-locked loops offer faster turn-on but at higher power consumption and noise levels, lacking a viable technique to eliminate the need for multiple crystal sources.
Innovation Solution
A frequency generator integrated circuit calibrated with a single high accuracy reference frequency, using semiconductor technology to generate multiple clock frequencies, reducing component count, power consumption, and phase noise, while consolidating multiple frequency sources into a single chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple quartz crystals are used for frequency generation, then frequency accuracy and stability are improved, but device size and power consumption increase
Solution Approach 1:
The patent combines multiple frequency generation functions into a single integrated circuit that uses one reference crystal with multiple voltage-controlled oscillators (VCOs). Each VCO can be independently calibrated to generate different frequencies (e.g., 32.768 kHz, 1.024 MHz, 4.096 MHz) from the same reference source, eliminating the need for multiple separate crystal oscillators while maintaining frequency accuracy and reducing power consumption.
Solution Approach 2:
The integrated circuit provides multi-functionality by using a single reference crystal to generate multiple clock frequencies through programmable VCOs. The system can operate in different modes (single-frequency, multi-frequency, spread-spectrum) and can be configured via I2C interface to meet various frequency generation requirements, making one device replace multiple dedicated frequency sources.
2Reliability
If multiple quartz crystals are used for frequency generation, then frequency accuracy is improved, but device area increases
Solution Approach 1:
The patent integrates multiple frequency generation functions into a single chip that occupies minimal board space. By combining the reference crystal, multiple VCOs, calibration circuits, and control logic into one integrated circuit, the physical footprint is dramatically reduced compared to using multiple separate crystal oscillators, each requiring its own mounting space and associated circuitry.
3Speed
If phase-locked loops are used for frequency generation, then turn-on speed is improved, but power consumption and phase noise increase
Solution Approach 1:
The patent implements dynamic frequency tuning through voltage-controlled oscillators that can be rapidly adjusted via digital-to-analog converters controlled by the microcontroller. This allows fast frequency switching and turn-on without the phase noise and power consumption penalties of traditional phase-locked loops, as the VCOs can be directly programmed to desired frequencies without requiring phase locking acquisition time.
4Device complexity
If a single reference frequency is used to generate multiple clock frequencies, then component count is reduced, but frequency accuracy may be compromised
Solution Approach 1:
The patent incorporates calibration circuits that use feedback mechanisms to adjust and trim the output frequencies of each VCO. During calibration, the system measures the actual frequencies generated by each VCO and applies corrective voltage adjustments through DACs to ensure each output frequency meets specified accuracy requirements, even though all frequencies originate from a single reference crystal.
Data Source
AI summary
An integrated circuit frequency generator is disclosed. In some embodiments, the frequency generator comprises an electronic oscillator configured to generate an oscillator frequency, calibration circuitry configured to periodically calibrate the electronic oscillator with respect to a reference frequency at a first calibration frequency when at a steady state temperature and at a second calibration frequency when at a transient temperature, and circuitry configured to generate an output frequency from the oscillator frequency.