Multi-Mode Analog Baseband Filter with Dynamic Capacitor Switching
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Solution Overview
Problem
Existing analog baseband filters for multi-mode and multi-band wireless transceivers face challenges in accurately setting cut-off frequencies due to temperature and process variations, leading to increased circuit area and noise, especially when handling diverse bandwidths like 2G and 3G/4G, which results in inefficient resource usage and signal degradation.
Innovation Solution
The implementation of a multi-mode and multi-band analog baseband filter apparatus with a switching unit that connects RF units to filter blocks based on selected communication modes, allowing for the sharing of signal chains and capacitor regions between high-band and low-band modes, thereby optimizing resistor and capacitor usage and reducing circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate filter circuits are designed for 2G and 3G/4G modes, then each mode can be optimized independently, but the overall circuit area increases significantly
Solution Approach 1:
The patent implements a universal filter circuit that can operate in both 2G and 3G/4G modes by dynamically reconfiguring capacitor connections. The same physical filter circuit serves multiple functions across different communication standards, eliminating the need for separate dedicated circuits for each mode while maintaining optimized performance for both.
Solution Approach 2:
The patent employs dynamic reconfiguration of capacitor connections through switching mechanisms that adjust the filter circuit's characteristics based on the operating mode. Capacitors are connected or disconnected from specific nodes depending on whether 2G or 3G/4G mode is active, allowing the circuit to adapt its behavior dynamically rather than being fixed for a single mode.
2Measurement precision
If large-value resistors and capacitors are used for low-band (2G) filtering, then the cut-off frequency can be accurately set, but the circuit area increases several times
Solution Approach 1:
The patent uses dynamic capacitor switching to achieve large effective capacitance values only when needed for 2G mode operation. By connecting capacitors in parallel through switching mechanisms, the circuit obtains the required large capacitance for low-band filtering temporarily, then disconnects them when operating in 3G/4G mode, avoiding the permanent area occupation that would result from always including such large capacitors.
Solution Approach 2:
The patent divides the capacitor bank into multiple segments that can be independently connected or disconnected based on operating mode requirements. Instead of using a single large capacitor that occupies maximum area always, the capacitor is segmented into smaller units that are activated only when their capacity is needed, reducing the effective area occupation while maintaining the ability to achieve large capacitance values when required.
3Adaptability or versatility
If the circuit area is increased to support diverse bandwidths, then all communication modes can be supported, but noise increases and signal characteristics degrade
Solution Approach 1:
The patent dynamically activates only the necessary circuit components for the current operating mode. By switching capacitor connections based on whether 2G or 3G/4G mode is active, the circuit minimizes the number of active components at any given time, thereby reducing the overall noise floor and avoiding signal degradation that would result from having all components permanently active in a large-area design.
4Measurement precision
If digital correction algorithms are used to adjust cut-off frequency, then temperature and process variations can be compensated, but computational resources and power consumption increase
Solution Approach 1:
The patent replaces digital correction algorithms with an analog switching mechanism that physically reconfigures the filter circuit's capacitor connections based on operating mode. This mechanical/electrical switching approach achieves frequency accuracy adaptation without requiring complex digital computation, thereby significantly reducing power consumption and computational resource usage while maintaining cut-off frequency precision.
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 reduces circuit area by half, decreases noise, and enhances signal processing efficiency across various communication standards, supporting a wide range of bandwidths while minimizing power and computational resources.
Implementation Method 1
the first capacitor included in the first capacitor region of the first filter block is connected to the second capacitor included in the second capacitor region of the second filter block
Data Source
Figure 1~2A
Figure 2B
Figure 3A
AI summary
An analog, baseband filter apparatus for a multi-mode and multi-band wireless transceiver and a method for controlling the analog baseband filter apparatus are provided. The analog baseband filter apparatus includes a plurality of Radio Frequency (RF) units, each of the plurality of RF units being for receiving RF signals of one of a plurality of frequency bands and outputting baseband signals, a plurality of filter blocks for filtering and amplifying the baseband signals, and a switching unit for connecting at least two of the plurality of RF units to at least one of the plurality of filter blocks according to a selected communication mode, wherein the at least one of the plurality of filter blocks is configured to be connected to a capacitor region (C11,C21,C2,C22) of an adjacent filter block from among the plurality of filter blocks.