Hybrid Resistive RDAC Echo Cancellation for Low-Power Transceivers
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Solution Overview
Problem
Conventional transceiver technologies face issues with increased power consumption and silicon real estate usage due to the reliance on active and/or passive filters for echo rejection, which are inefficient in managing transmit signal leakage into receive paths.
Innovation Solution
Integration of a passive hybrid resistive network into the transmit path of a resistive digital-to-analog converter to perform echo cancellation, utilizing a differential resistor-based digital-to-analog converter (RDAC) with a positive and negative stage, and a differential receiver to electrically couple resistors and MOSFETs for signal inversion and coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional active and/or passive filters are used for echo rejection, then transmit signal leakage can be filtered, but power consumption increases and silicon real estate usage increases
Solution Approach 1:
The patent combines the echo rejection function with the existing DAC structure by integrating a passive resistive hybrid network into the transmit path. This merging approach eliminates the need for separate active filters, thereby reducing power consumption while maintaining echo rejection capability. The hybrid network is electrically coupled to the DAC outputs and receiver inputs, allowing it to perform echo cancellation as part of the signal path rather than as a separate processing stage.
Solution Approach 2:
The patent replaces active filter circuits with a passive resistive hybrid network. This substitution eliminates the need for active components (operational amplifiers, transistors) that consume power, using only passive resistive elements that do not require power supply. The passive nature of the hybrid network directly addresses the power consumption issue while maintaining the signal filtering function.
2Object-affected harmful factors
If conventional active and/or passive filters are used for echo rejection, then transmit signal leakage can be filtered, but silicon real estate usage increases
Solution Approach 1:
The patent integrates the echo rejection functionality into the existing DAC circuitry by adding a passive resistive hybrid network that shares the same physical space and signal path. This consolidation eliminates the need for separate filter circuits, reducing the overall silicon area required. The hybrid network is coupled to the DAC outputs and receiver inputs, performing echo cancellation within the existing transceiver footprint.
Solution Approach 2:
The patent replaces bulky active filter circuits with a compact passive resistive hybrid network. Passive resistive elements occupy significantly less silicon area compared to active filter components (operational amplifiers, capacitors, inductors). This substitution directly reduces the silicon real estate requirement while maintaining the echo rejection function.
3Use of energy by moving object
If passive hybrid resistive network is integrated into transmit path, then power consumption and silicon real estate are reduced, but echo cancellation performance must be maintained
Solution Approach 1:
The patent optimizes the resistance values of the hybrid network components to achieve effective echo cancellation. By carefully selecting and tuning the resistance parameters of the passive resistive elements, the system maintains high echo rejection performance despite using a simpler passive structure. The resistance values are designed to match the impedance characteristics of the transmit and receive paths, ensuring optimal signal cancellation.
Solution Approach 2:
The passive resistive hybrid network acts as an intermediary element between the DAC outputs and the receiver inputs. It mediates the signal paths to enable echo cancellation without requiring active components. The hybrid network processes the signals passively, maintaining signal integrity while rejecting echo, thus preserving reliability without power consumption.
Data Source
AI summary
A differential resistor-based digital-to-analog converter (RDAC) can include a positive digital-to-analog converter (PDAC) stage and a negative digital-to-analog converter (NDAC) stage. A first network of resistors of the PDAC stage can be electrically coupled to a second network of resistors of the NDAC stage utilizing an intermediary network of resistors. Further, a differential receiver can include a first input and a second input. The first input can be electrically coupled to a first resistor of the intermediary network of resistors, and the second input can be electrically coupled to a second resistor of the intermediary network of resistors. Furthermore, a portion of the first network of resistors can be electrically coupled to a positive output of the RDAC, and another portion of the second network of resistors can be electrically coupled to a negative output of the RDAC.