Wide-Range VCO Delay Cell With Parallel Current Paths
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Solution Overview
Problem
Existing Phase Lock Loops (PLLs) are limited to a narrow frequency range, requiring multiple designs for different frequencies, which increases complexity and power consumption, and often necessitate start-up circuitry that complicates the system.
Innovation Solution
A wide frequency range Voltage Controlled Oscillator (VCO) architecture with parallel current sources in each delay cell, allowing the VCO to operate across a wide frequency range without additional start-up circuitry, by providing an alternate current path when the bias circuit saturates or during initialization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a narrow frequency range PLL design is used, then the design is simpler and consumes less power, but multiple designs are required for different frequencies
Solution Approach 1:
The VCO is designed with parallel current sources that enable a single circuit architecture to operate across multiple frequency ranges (50 MHz to 3 GHz). The first current source enables wide frequency operation while the second current source provides biasing, allowing the same circuit to serve multiple frequency requirements without needing separate dedicated circuits for each frequency range.
Solution Approach 2:
The patent implements dynamic switching between parallel current sources based on operating conditions. The voltage control input dynamically adjusts the operation of the first current source to enable wide frequency tuning, while the bias voltage input controls the second current source to maintain proper biasing throughout the frequency range, allowing adaptive operation across varying frequency requirements.
2Adaptability or versatility
If start-up circuitry is added to enable wide frequency operation, then frequency range is improved, but device complexity increases
Solution Approach 1:
The parallel current source configuration provides self-starting capability without requiring external start-up circuitry. The first current source automatically provides the necessary current path during initialization and saturation conditions, enabling the VCO to self-start and maintain operation across the full frequency range without additional control circuits.
Solution Approach 2:
The first current source acts as an intermediary that provides an alternate current path during transition and saturation conditions. This intermediate current path enables smooth operation during frequency transitions and initialization without requiring complex start-up control logic or additional circuitry to manage the transitions.
3Use of energy by moving object
If the bias circuit operates at saturation, then power consumption is reduced, but the VCO frequency range is limited
Solution Approach 1:
The system dynamically switches between the first and second current sources based on operating conditions. During normal operation, the second current source provides biasing while the first current source enables wide frequency tuning. During saturation or initialization, the roles reverse, with the first current source providing the main current path. This dynamic role reversal maintains wide frequency range capability while allowing efficient saturation operation.
Solution Approach 2:
The patent changes the operational parameters of the parallel current sources based on the operating state. The voltage control input and bias voltage input independently adjust the current levels and switching behavior of the first and second current sources, respectively. This parameter control enables the system to operate in saturation mode for power efficiency while maintaining the capability to access the full frequency range when needed.
Data Source
AI summary
Systems and methods are disclosed for wide frequency range voltage controlled oscillators. For example, an apparatus includes a Voltage Controlled Oscillator (VCO) including a delay cell which includes first and second current sources provided in parallel with one another. The first current source is controlled by a voltage control input connected to a voltage control terminal and the second current source is controlled by a bias voltage input connected to a bias voltage terminal. The first current source provides an alternate current path in the delay cell when the second current source is off. The delay cell is operable to receive an input and produce an output using the alternate current path.