Wideband Channel-Selective Amplifier for Blocker Rejection
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Solution Overview
Problem
Conventional communication systems require multiple transceivers for different frequency bands and protocols, leading to increased area, cost, and complexity, as well as the need for expensive off-chip filtering components to manage blockers.
Innovation Solution
A wide-band low noise amplifier with built-in filter capabilities that can be tuned to any desired channel center frequency and bandwidth, utilizing an inverter-based wideband transconductance stage with source follower driven resistive feedback and a common gate, channel-selective transimpedance stage based on N-path staggered tuned mixer circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate transceivers are used for different frequency bands and protocols, then each transceiver can be optimized for its specific band, but the total circuit area, cost, and system complexity increase significantly
Solution Approach 1:
The patent combines multiple separate transceivers into a single integrated transceiver that can operate across multiple frequency bands and protocols. The amplifier structure uses a bank of switchable filter sections that can be configured to support different frequency bands, eliminating the need for multiple separate transceiver circuits while maintaining band-specific optimization through software-controlled filter selection.
Solution Approach 2:
The amplifier is designed with universal functionality to operate across multiple frequency bands (sub-6 GHz and mmWave) and support multiple communication protocols. The filter bank architecture allows the same physical hardware to be reconfigured for different bands through switching mechanisms, providing multi-functionality without requiring separate dedicated circuits for each band.
2Adaptability or versatility
If conventional resistive feedback wideband LNA is used, then wideband operation is achieved, but channel selectivity is lost and compression occurs due to strong blockers
Solution Approach 1:
The amplifier is segmented into multiple parallel paths, each containing a switchable filter section tuned to specific frequency bands. This segmentation allows the wideband amplifier to maintain channel selectivity by activating only the filter section corresponding to the desired channel, while keeping other sections inactive to avoid interference and compression from blockers in other bands.
Solution Approach 2:
The filter bank employs dynamic switching mechanisms that can reconfigure which filter sections are active based on the desired operating frequency and channel. This dynamic reconfiguration allows the amplifier to adapt its frequency response in real-time, maintaining both wideband capability and channel selectivity by selectively enabling appropriate filter sections as signal conditions change.
3Reliability
If channel-selective wideband mixer topologies are used, then channel selectivity is achieved, but noise figure becomes very high
Solution Approach 1:
The filter sections perform preliminary channel selection before the signal reaches the mixing stage. By pre-filtering the input signal to remove out-of-band blockers and interference, the subsequent mixer operates on a cleaner signal, which significantly reduces the noise figure compared to channel-selective mixer topologies where filtering occurs after mixing.
Solution Approach 2:
The filter bank acts as an intermediary between the wideband amplifier and the mixer stage. This intermediary component selectively passes desired frequency components while attenuating others before they reach the mixer, thereby achieving channel selectivity without degrading the noise figure of the overall system.
4Reliability
If off-chip filtering components are used to reject blockers, then channel selectivity and blocker rejection are improved, but cost and device area increase
Solution Approach 1:
The filter sections are nested within the amplifier chip itself, integrating what would traditionally be separate off-chip components into the main amplifier die. This nesting approach allows multiple filter sections to be packed into the chip area using standard CMOS fabrication processes, significantly reducing the overall device area compared to external filtering components while maintaining blocker rejection performance.
Data Source
AI summary
An amplifier structure may include a first amplifier substructure having a first amplifier and a first filter structure and provide a first high frequency output signal and a first low frequency output signal having a frequency lower than a frequency of the first high frequency output signal. It may include a second amplifier substructure having a second amplifier and a second filter structure and provide a second high frequency output signal and a second low frequency output signal having a frequency lower than the frequency of the second high frequency output signal. It may include a first combination node configured to receive the first high frequency output signal and the second low frequency output signal and to provide a first amplified signal, and a second combination node configured to receive the first low frequency output signal and the second high frequency output signal and to provide a second amplified signal.