Frequency Divider Bias Shaping for Temperature-Dependent Low Power
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Solution Overview
Problem
Existing frequency dividers in wireless communication transceivers consume excessive power due to fixed operating points and inefficiencies in LO buffer distribution, leading to increased power consumption even under optimal conditions, which is detrimental for low-power applications like wireless sensor networks and mobile devices.
Innovation Solution
The implementation of a bias-current shaping technique that adjusts power consumption in frequency dividers based on temperature changes, using a temperature-dependent bias current and eliminating power-hungry LO buffers, while employing an impedance transformation network to reduce resistive loading, thereby optimizing power usage across various process and temperature corners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed operating point is used for the frequency divider to ensure reliable functionality at worst-case conditions, then reliability is improved, but power consumption increases significantly
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed operating point to a dynamic bias current that adapts to actual circuit conditions. The bias current is modulated based on detected frequency divider performance metrics, allowing the system to operate at optimal power levels while maintaining reliability. This resolves the contradiction by making the operating point variable rather than static, enabling low-power operation under normal conditions while ensuring reliability when needed.
Solution Approach 2:
The patent implements feedback by detecting the actual performance of the frequency divider and using this information to adjust the bias current. The system monitors frequency divider operation and dynamically modifies the bias current to maintain reliable functionality while minimizing power consumption. This feedback mechanism allows the system to avoid the excessive power consumption of fixed worst-case design while ensuring reliability is maintained through active monitoring and adjustment.
2Reliability
If LO buffers are used to distribute the LO signal to frequency dividers, then signal distribution reliability is improved, but power consumption increases
Solution Approach 1:
The patent extracts and removes the LO buffers from the signal distribution path, replacing them with an alternative approach that eliminates the power-hungry buffering stage. By taking out the LO buffers, the system achieves significant power savings while maintaining signal distribution functionality through direct coupling or alternative distribution mechanisms that do not require high-power amplification stages.
Solution Approach 2:
The patent introduces an intermediary mechanism to replace the LO buffers in signal distribution. Instead of using power-consuming buffer amplifiers, the system employs an intermediate coupling method (such as direct signal routing or passive distribution networks) that transfers the LO signal to frequency dividers without requiring active buffering, thereby eliminating the power consumption associated with LO buffers while maintaining distribution reliability.
3Use of energy by moving object
If inductive elements are used to resonate with parasitic capacitances and reduce power consumption, then power consumption is reduced, but device area increases significantly
Solution Approach 1:
The patent substitutes the mechanical/physical inductive elements with an electrical control mechanism. Instead of using large physical inductors to resonate with parasitic capacitances, the system employs electronic bias current control and modulation techniques to achieve the same power reduction effect. This substitution replaces bulky passive components with compact active control circuitry, maintaining power efficiency benefits while dramatically reducing the required device area.
Solution Approach 2:
The patent changes the operating parameters of the frequency divider circuit, specifically the bias current characteristics, to achieve power reduction without requiring large inductive elements. By dynamically adjusting bias current levels and timing parameters, the system optimizes power consumption while avoiding the need for physical resonance circuits that would occupy significant silicon area. This parameter-based approach achieves power efficiency through control rather than through large passive components.
Data Source
AI summary
A bias-shaping circuit for adjusting power consumption in a frequency divider to a temperature-dependent minimum includes a temperature-dependent bias source for producing a temperature-dependent bias. The bias is combined with an input signal to create an output bias. The output bias changes in response to a change in temperature to compensate for at least a portion of a temperature-induced change in the frequency divider, thereby adjusting power consumption in the frequency divider to a temperature-dependent minimum.