Digital Ring Oscillator Instant Synchronization
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Solution Overview
Problem
Existing oscillator technologies, such as Voltage-Controlled Oscillators (VCO) and Phase Locked Loops (PLL), face challenges in achieving instant synchronization with external signals, consuming excessive power, and producing jitter due to analog circuitry, which limits their ability to provide frequencies on demand without significant time delays.
Innovation Solution
A digital ring oscillator circuit that can be turned on and off instantly, using coarse and fine frequency adjustments to synchronize with an external clock signal, producing multiple frequencies by digital division, and maintaining synchronization without relying on VCO or Delay Locked Loop methods, utilizing silicon hardware delays for frequency control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If VCO and PLL circuitry are used to synchronize with external signals, then frequency multiplication capability is achieved, but synchronization time delay increases and power consumption increases
Solution Approach 1:
The patent replaces analog VCO and PLL circuitry with a digital ring oscillator implementation. The ring oscillator uses digital logic gates (NAND, NOR, NOT gates) arranged in a feedback loop to generate oscillating signals, eliminating the need for analog voltage-controlled oscillation and phase-locked loop mechanisms. This digital approach reduces power consumption while maintaining frequency multiplication capability through integer division of the oscillation frequency.
Solution Approach 2:
The patent changes the fundamental operating parameters by using a free-running digital oscillator with a fixed high frequency that is then divided down to match the external clock frequency, rather than using an analog oscillator that must continuously adjust its frequency to lock onto the external signal. This parameter change eliminates the synchronization delay inherent in analog frequency adjustment while reducing power consumption.
2Speed
If VCO is used to derive application frequencies through division, then frequency multiplication is achieved, but synchronization time delay increases significantly
Solution Approach 1:
The ring oscillator is designed to free-run at a predetermined high frequency that is an integer multiple of the external clock frequency. This preliminary action of pre-establishing the oscillation at the correct frequency relationship eliminates the need for time-consuming frequency adjustment and phase locking, allowing immediate frequency multiplication upon activation.
Solution Approach 2:
The patent replaces the analog frequency adjustment mechanism of VCO with a digital frequency division approach. The digital ring oscillator generates a high-frequency signal that is then divided by an integer factor to produce the desired output frequency, eliminating the synchronization delay inherent in analog frequency tuning and phase locking processes.
3Reliability
If analog VCO circuitry is used for frequency generation, then continuous frequency adjustment is possible, but jitter is produced and power consumption increases
Solution Approach 1:
The patent substitutes analog VCO circuitry with a digital ring oscillator composed of logic gates. This digital implementation eliminates the jitter inherent in analog oscillators that results from voltage variations and component tolerances. The digital logic gates provide stable, clean transitions with consistent timing, producing a more reliable clock signal suitable for synchronous digital systems.
Solution Approach 2:
The patent changes from analog voltage-controlled frequency adjustment to digital frequency determination through gate delay characteristics. The oscillation frequency is determined by the propagation delays of the digital logic gates, which provide stable and repeatable timing characteristics compared to analog circuits susceptible to voltage noise and component variations, thereby reducing jitter.
4Reliability
If PLL and DLL circuitry are used for clock synchronization, then frequency matching is achieved, but excessive power is consumed
Solution Approach 1:
The patent replaces power-hungry PLL and DLL circuitry with a simple digital ring oscillator. The ring oscillator requires only the logic gates necessary to create the feedback loop, consuming significantly less power than analog PLL/DLL implementations that require voltage-controlled oscillators, phase comparators, charge pumps, and frequency dividers. The digital approach achieves clock synchronization through frequency division rather than continuous analog adjustment.
Solution Approach 2:
The patent extracts only the essential frequency generation and division functionality from complex PLL/DLL systems. By using a free-running ring oscillator with integer frequency division, the design eliminates unnecessary analog control circuitry while retaining the core function of generating synchronized clock signals, thereby reducing power consumption.
Data Source
AI summary
A High Frequency Digital Oscillator contains a ring oscillator having an output fn, and having coarse and fine frequency adjustments, wherein the input signal f1 is the input to both the ring oscillator and the High-Frequency Digital Oscillator, which has a multiplicity of output signals including f2, f4, and f8 at one-half, one fourth, and one-eighth the frequency of fn respectively, and wherein an input gating signal causes the oscillator to start or stop, a signal fc=1/4*(f4) causing a coarse frequency adjustment and a signal A=(1/f1−1/fc) making a fine adjustment, and by stopping the new output before the rising edge of f1; and then restarting starting the new output at the rising edge of so that the output and input are synchronized.