Oscillator Frequency Calibration Using Digital Pulse Feedback
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Solution Overview
Problem
Existing oscillator calibration methods are inefficient, consuming significant test time and device die area, due to variations in semiconductor processing that affect oscillator frequency outputs.
Innovation Solution
A frequency calibration device comprising a phase frequency detector and pulse generator that produce pulses to adjust the frequency of a target oscillator signal relative to a reference oscillator signal, using a counter to modify digital bit values and trigger incremental changes in the oscillator's frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If known oscillator calibration techniques are used, then oscillator frequency can be calibrated to reference frequency, but test time is significantly consumed
Solution Approach 1:
The patent replaces traditional mechanical/circuit-based frequency measurement and adjustment mechanisms with a digital system. A phase frequency detector digitally compares the target oscillator frequency with reference frequency, and a pulse generator digitally adjusts the oscillator frequency through pulse-width modulation, eliminating the need for physical component adjustments and reducing test time
Solution Approach 2:
The calibration system performs self-adjustment through automatic feedback control. The phase frequency detector continuously monitors frequency deviation and the pulse generator automatically corrects it without external intervention, enabling rapid iterative calibration that reduces test time while maintaining precision
2Measurement precision
If known oscillator calibration techniques are implemented in hardware, then frequency calibration can be performed, but device die area is significantly occupied
Solution Approach 1:
The pulse generator serves multiple functions: it generates calibration pulses, modulates oscillator frequency, and enables bidirectional frequency adjustment (increase and decrease). This multi-functionality consolidates what would traditionally require separate hardware circuits into a single integrated component, reducing die area while maintaining calibration precision
Solution Approach 2:
The system changes the operational parameters of the oscillator dynamically through digital pulse width modulation rather than physically changing component values. This allows frequency calibration without requiring additional physical components or large resistor/capacitor networks, thereby reducing the area occupied on the device die
Data Source
AI summary
In one general aspect, an apparatus can include a phase frequency detector configured to produce a plurality of indicators of relative differences between a frequency of a target oscillator signal and a frequency of a reference oscillator signal. The apparatus can also include a pulse generator configured to produce a plurality of pulses based on the plurality of indicators. The plurality of pulses can include a first portion configured to trigger an increase in the frequency of the target oscillator signal and the plurality of pulses including a second portion configured to trigger a decrease in the frequency of the target oscillator signal.