Hybrid LC Filter Topology for Low-Droop Wideband Transceivers
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Solution Overview
Problem
As signal bandwidth grows in 5G and New Radio cellular applications, active analog filters in transceivers consume excessive power, and passive filters with series inductors affect the quality factor, leading to undesirable voltage droop due to the interdependence of complex and real pole adjustments.
Innovation Solution
The restructured LC ladder filter separates real and complex poles by relocating resistors and capacitors from input ports to the feedback chain of an amplifier, allowing independent adjustment of these poles, thereby minimizing voltage droop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active analog filter is deployed to filter undesired frequency components, then linearity and noise performance are improved, but power consumption increases excessively
Solution Approach 1:
The filter is divided into two independent sections: a passive LC filter section for frequency selection and an active amplifier section for signal amplification. This segmentation allows the passive section to handle filtering without power consumption while the active section provides only amplification, reducing overall power consumption compared to a fully active filter design.
Solution Approach 2:
The patent combines passive LC filtering elements with an active amplifier in a hybrid configuration. The passive inductors and capacitors provide frequency-selective filtering, while the active amplifier provides signal amplification and compensation for losses, creating a merged system that achieves both low power consumption and good signal quality.
2Use of energy by moving object
If a passive filter is implemented to decrease power consumption, then power consumption is reduced, but voltage droop occurs due to quality factor effects
Solution Approach 1:
The patent merges a passive LC filter with an active amplifier to create a hybrid filter. The passive section provides frequency selection with low power consumption, while the active amplifier section compensates for voltage droop and quality factor limitations, maintaining voltage stability across the transceiver.
Solution Approach 2:
The active amplifier acts as an intermediary element between the passive filter components and the load. It compensates for the voltage droop caused by the passive filter's quality factor effects, thereby maintaining stable voltage output while preserving the low power consumption benefits of the passive filter.
3Measurement precision
If series inductors are added to a passive filter, then frequency selectivity is improved, but complex and real poles become interdependent, leading to voltage droop
Solution Approach 1:
The filter circuit is segmented into independent pole adjustment mechanisms. The series inductors in the passive section provide frequency selectivity and define complex poles, while the feedback resistors in the active section independently control real poles. This segmentation eliminates the interdependence between complex and real pole adjustments, preventing voltage droop.
Solution Approach 2:
Feedback resistors are introduced as intermediary elements that decouple the pole adjustment mechanisms. These resistors allow independent control of real poles through feedback paths, separating the influence of series inductors on complex poles from their unwanted effect on real poles, thereby maintaining voltage stability while preserving frequency selectivity.
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 approach enables efficient power management by allowing independent adjustment of real and complex poles, reducing voltage droop and enhancing the performance of transceiver filters.
Implementation Method 1
active analog filters may be deployed to filter undesired frequency components
Implementation Method 2
a first capacitor coupled in parallel to the first input port and the second input port, the first capacitor may adjust the complex pole of the filter circuitry
Implementation Method 3
receiver filter circuitry may include an amplifier
Data Source
AI summary
This disclosure is directed to filtering in a transceiver of an electronic device. In some instances, active analog filters may be deployed in the transceiver of the electronic device to achieve greater linearity and/or reduce noise in the transceiver. However, as signal bandwidth grows increasingly larger, an active analog filter may consume excessive power. To remedy the excessive power consumption, a passive ladder LC filter may be used. Some LC ladder filters may include a limited quality factor (Q), which may lead to undesirable effects in the transceiver (e.g., voltage droop). To address these undesirable effects, certain components in the LC ladder filter may be relocated from an input port to a feedback chain of an amplifier coupled to the LC ladder filter. The new structure may enable components in the LC ladder filter to be tuned without causing additional voltage droop across the LC ladder filter.