Dual-Mode Frequency Synthesizer Sharing TX Components
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Solution Overview
Problem
Conventional frequency synthesizers occupy significant die area due to large voltage sources and inductors, and low-power frequency synthesizers are underutilized in communications devices, particularly when in low-power mode, where only data reception occurs.
Innovation Solution
A dual-mode frequency synthesizer is implemented, sharing components like voltage sources and inductors with the transmit chain, allowing the same components to function as either a mixer in normal mode or a low-power frequency synthesizer in low-power mode, reducing overall footprint without performance sacrifice.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional frequency synthesizer is used for both normal and low-power modes, then the device can maintain connection and receive broadcast data in sleep mode, but the die area is significantly increased due to dedicated low-power synthesizer components
Solution Approach 1:
The transmit chain components (mixer, voltage source, inductors) are designed to serve dual purposes: functioning as a mixer during normal operation and as a low-power frequency synthesizer during sleep mode. This multi-functionality eliminates the need for separate dedicated components, reducing die area while maintaining low-power reception capability
Solution Approach 2:
The patent merges the low-power frequency synthesizer components with the existing transmit chain by sharing the mixer, voltage source, and inductors between the two functional modes. This consolidation integrates what would traditionally be separate circuits into a unified structure, achieving area reduction without sacrificing low-power mode functionality
2Reliability
If separate frequency synthesizers are implemented for normal and low-power modes, then each mode has optimized signal processing capabilities, but the device complexity and footprint are increased
Solution Approach 1:
The system dynamically reconfigures the shared transmit chain components between two operational states: mixer mode during normal operation and frequency synthesizer mode during low-power sleep mode. This dynamic switching allows a single set of components to fulfill the signal processing requirements of both modes, maintaining reliability while reducing complexity
Solution Approach 2:
The transmit chain components are designed with universal functionality to perform both mixing operations during active transmission and frequency synthesis operations during reception in sleep mode. This dual capability ensures that signal processing requirements for both normal and low-power modes are met using the same hardware, thereby reducing overall device complexity
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
This configuration minimizes the die size of communications devices by leveraging shared circuitry for both normal and low-power modes, ensuring efficient power usage and reduced footprint without compromising signal processing capabilities.
Implementation Method 1
the second frequency synthesizer includes a voltage-controlled oscillator (VCO) to generate the second LO signal based at least in part on oscillating current in an inductor-capacitor (LC) tank circuit
Data Source
AI summary
An analog front-end (AFE) for a communications device includes a low-power frequency synthesizer with reduced footprint. The AFE includes a first frequency synthesizer and a second frequency synthesizer. The first frequency synthesizer is coupled to a transmit (TX) chain and to a receive (RX) chain of the AFE. The first frequency synthesizer is to generate a first local oscillator (LO) signal for transmitting or receiving carrier signals when the device is in a normal operating mode. The second frequency synthesizer is coupled to the RX chain and shares one or more components of the TX chain. The second frequency synthesizer is to utilize the one or more shared components to generate a second LO signal for receiving carrier signals when the device operates in a low-power mode. For example, the one or more shared components may include a voltage source and/or one or more inductors.