VCO Open-Loop Offset Correction for Low-Power PLL Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing signal synthesis devices struggle to accurately correct the offset of an open loop during low-power operation in PLL circuits, particularly in IoT devices that require long-term operation without battery replacement.
Innovation Solution
A signal synthesis apparatus and method that includes a voltage-controlled oscillator (VCO), an energy storage unit, a VCO input selector, and a digital controller. The digital controller calculates frequency offsets between closed and open loop modes and adjusts the modulation control signal to compensate for these offsets, ensuring accurate frequency output even during low-power operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the PLL circuit operates in open loop mode for low-power operation, then energy consumption is reduced, but frequency accuracy deteriorates due to open loop offset
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing offset compensation values for different capacitor combinations in a lookup table before open loop operation. The digital controller retrieves the appropriate compensation value based on the current capacitor connection state, allowing immediate correction without real-time closed loop feedback, thus maintaining frequency accuracy while operating in low-power open loop mode.
Solution Approach 2:
The patent changes the parameter of voltage input to the VCO by adding an offset voltage based on the retrieved compensation value. This parameter adjustment compensates for the open loop offset, ensuring that the VCO output frequency remains accurate even when operating without closed loop feedback.
2Measurement precision
If the PLL circuit operates in closed loop mode for accurate frequency, then frequency accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent implements dynamic operation mode switching between closed loop and open loop based on operational requirements. The system can transition from closed loop (high power, high accuracy) to open loop (low power, compensated accuracy) mode, optimizing the balance between energy consumption and frequency accuracy depending on the application context.
3Ease of manufacture
If manufacturing process variations occur, then device fabrication becomes easier, but frequency accuracy deteriorates due to process-induced offsets
Solution Approach 1:
The patent applies self-service by having the system automatically measure and characterize its own offset behavior during calibration, then use this self-acquired information to compensate for manufacturing variations. The lookup table is populated with compensation values specific to each device's actual characteristics, enabling each device to self-correct for its own process-induced deviations.
4Adaptability or versatility
If environmental changes such as temperature and humidity occur, then operational adaptability is improved, but frequency accuracy deteriorates due to environmental-induced offsets
Solution Approach 1:
The patent uses feedback by continuously monitoring the capacitor connection state and retrieving corresponding compensation values from the lookup table. This feedback mechanism allows the system to adapt to environmental changes by selecting the appropriate pre-calibrated compensation value that accounts for temperature and humidity effects on the specific capacitor combination being used.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively corrects frequency deviations caused by manufacturing processes and environmental changes, enabling accurate frequency output and efficient low-power operation in IoT devices.
Implementation Method 1
a voltage-controlled oscillator (VCO) which generates an output signal having a frequency corresponding to an input voltage by including a modulation cap bank having a plurality of capacitors of the same capacitance and an inductor
Implementation Method 2
an energy storage unit which stores energy using an input voltage and outputs a voltage based on the stored energy
Data Source
AI summary
Disclosed is technology related to a signal synthesis apparatus that corrects an offset between a closed loop and an open loop to output a frequency-modulated signal. The signal synthesis apparatus includes a VCO configured to modulate and output a frequency signal in response to an input voltage by including a modulation cap bank having a plurality of capacitors, an energy storage unit configured to output a voltage using stored energy, a VCO input selector configured to connect the VCO to input of the energy storage unit in the case of a closed loop mode and connect the VCO to output of the energy storage unit in the case of an open loop mode, and a digital controller configured to control an operation mode of the VCO input selector and transmit a modulation control signal for adjusting a connection state of the capacitors of the modulation cap bank to the VCO.