Voltage-Controlled Oscillator Differential Input Proportionality
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Solution Overview
Problem
Conventional voltage-controlled oscillators lose proportionality between oscillation signals and control voltages when the control voltage becomes a high frequency signal, leading to increased power consumption and inefficiency, especially when processing differential signals.
Innovation Solution
A voltage-controlled oscillator design that includes a voltage-current converter with a unique transistor configuration and ring oscillators, which maintains proportionality between control voltages and oscillation signals even at high frequencies, using a differential control voltage scheme to ensure linear output currents and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transistors of the operational amplifier are driven at high speeds to maintain proportionality between output current and control voltage, then proportionality is improved, but power consumption increases
Solution Approach 1:
The patent changes the operating parameters by using a differential voltage input structure instead of a single-ended voltage input. This allows the transistors to operate in a more efficient regime where proportionality is maintained without requiring excessively high drive speeds, thus reducing power consumption while preserving the linear relationship between control voltage and output current.
Solution Approach 2:
The patent segments the single control voltage input into two differential control voltage inputs (first control voltage and second control voltage). This segmentation allows the circuit to process the control signal in a differential manner, improving proportionality accuracy without requiring the transistors to operate at unnecessarily high speeds, thereby reducing power consumption.
2Device complexity
If a single-end input type voltage-current converter is used, then circuit simplicity is improved, but the ability to process differential signals deteriorates
Solution Approach 1:
The patent implements a dynamic differential input structure where the circuit can adapt to differential control voltages. The first and second transistors are configured to receive differential control voltages, enabling the voltage-current converter to dynamically process differential signals while maintaining a relatively simple circuit structure through efficient use of transistor pairs and current mirrors.
3Adaptability or versatility
If two current control circuits are used to process differential signals, then differential signal processing capability is improved, but device complexity increases
Solution Approach 1:
The patent merges two current control functions into a single integrated voltage-current converter circuit. By using a differential input structure with paired transistors and current mirrors, the circuit achieves differential signal processing capability while avoiding the complexity of two separate independent control circuits. The merging is achieved through shared current mirrors and integrated transistor pairs that simultaneously handle both differential inputs.
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 achieves oscillation signals with good proportionality to control voltage changes while minimizing power consumption, even with high frequency signals, and enables precise analog-digital conversion with low power usage.
Implementation Method 1
a voltage-current converter, which receives a first control voltage and a second control voltage and outputs a first output current proportional to the first control voltage and a second output current proportional to the second control voltage
Implementation Method 2
a first ring oscillator, which includes plural delay elements connected in a ring form and oscillates based on the first output current corresponding to the first control voltage
Data Source
AI summary
A voltage-controlled oscillator includes a voltage-current converter, a first ring oscillator and a second ring oscillator. The voltage-current converter includes a first transistor for receiving a first control voltage at its gate terminal, a second transistor for receiving a second control voltage at its gate terminal, a third transistor connected to the first transistor in series and has a gate terminal connected to a drain terminal of the first transistor, a fourth transistor connected to the second transistor in series and has a gate terminal connected to a drain terminal of the second transistor, a resistor connected to a source terminal of the first transistor and a source terminal of the second transistor, a fifth transistor having a gate terminal connected to the drain terminal of the first transistor, and a sixth transistor having a gate terminal connected to the drain terminal of the second transistor.