Voltage-to-Current Converter for Low-Gain VCO Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Voltage controlled oscillators require large gains to extend frequency range and cover PVT variations, but this leads to noise and supply pushing issues, and existing solutions either require digital calibration or have limited input range coverage.
Innovation Solution
A voltage-to-current converter with a current mirror and current generating circuit, coupled with a current controlled oscillator, which converts input voltage to output current and generates a frequency signal, achieving smaller gains and linear operation without digital calibration, covering most or the full input range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a voltage controlled oscillator uses a large gain to extend frequency range and cover PVT variation, then the frequency range and PVT coverage are improved, but noise and supply pushing issues worsen
Solution Approach 1:
The voltage controlled oscillator is divided into multiple sub-bands, each with smaller gain. This segmentation allows the oscillator to achieve extended frequency range and PVT coverage through multiple smaller-gain stages rather than one large-gain stage, thereby reducing noise and supply pushing in each individual sub-band while maintaining overall adaptability.
Solution Approach 2:
The patent implements dynamic switching between multiple sub-bands based on operating conditions. By dynamically selecting appropriate sub-bands and adjusting their activation, the system maintains optimal gain levels for different frequency ranges and PVT conditions, preventing noise and supply pushing while covering the full frequency range.
2Object-affected harmful factors
If a voltage controlled oscillator uses multiple sub-bands with smaller gains to prevent noise and supply pushing, then noise and supply pushing are reduced, but digital calibration is required which increases manufacturing cost
Solution Approach 1:
The voltage-to-current converter is designed with self-calibrating characteristics where the current mirror automatically adjusts to maintain accurate current relationships across sub-bands. This self-service mechanism eliminates the need for external digital calibration circuits, reducing manufacturing cost while maintaining low noise and supply pushing performance.
Solution Approach 2:
The patent introduces a specially designed current mirror as an intermediary element between voltage input and current output stages. This current mirror acts as a mediator that automatically compensates for variations and maintains precision without requiring digital calibration, thereby reducing device complexity while achieving the desired noise reduction.
3Device complexity
If a voltage controlled oscillator uses a linear input voltage characteristic with smaller gain, then gain is reduced and digital calibration is eliminated, but the linear range does not cover the full input range
Solution Approach 1:
The input voltage range is segmented into multiple sub-bands, each handled by a separate linear voltage-to-current converter operating at smaller gain. This segmentation allows each converter to maintain linearity within its specific range while collectively covering the full input range, eliminating the need for digital calibration and achieving both reduced complexity and full range coverage.
Solution Approach 2:
The system dynamically switches between multiple linear voltage-to-current converters, each optimized for a specific sub-range. By dynamically activating the appropriate converter based on the input voltage level, the system maintains linear operation across the full input range without requiring digital calibration, thereby achieving both reduced complexity and full adaptability.
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 prevents noise and supply pushing while maintaining linear operation across the input range, suitable for applications like NFC and RFID devices with simple and cost-effective circuit structures.
Implementation Method 1
the current mirror is coupled to the resistor, and is used for mirroring a reference current to generate a mirrored current
Implementation Method 2
the reference current is formed according to at least a current flowing through the resistor
Data Source
AI summary
A voltage controlled oscillator includes a voltage-to-current converter and a current controlled oscillator, where the voltage-to-current converter is used for converting an input voltage to generate an output current, and the current controlled oscillator is used for generating an output frequency signal according to the output current. In addition, the voltage-to-current converter includes an input terminal, a resistor, a current mirror and a current generating circuit, where the input terminal is for receiving the input voltage; the resistor is coupled to the input terminal; the current mirror is coupled to the resistor, and is used for mirroring a reference current to generate a mirrored current, where the reference current is formed according to at least a current flowing through the resistor; and the current generating circuit is coupled to the current mirror, and is used for generating the output current according to at least the mirrored current.