Current-Reuse Notch Filter Receiver for Out-of-Band Blocker Rejection
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Solution Overview
Problem
Existing wireless communication receivers face challenges in efficiently suppressing out-of-band blockers while minimizing power consumption, particularly in current-reuse architectures lacking notch filters and requiring high voltage supplies.
Innovation Solution
A current-reuse receiver topology integrated with a current-mode notch filter that reuses supply currents from post-mixer and gain stages to power the low noise transconductance amplifier (LNTA) stage, utilizing a passive mixer and operational transconductance amplifier (OTA) with an RC network for effective blocker attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional high-order filters are used to eliminate out-of-band blockers, then blocker rejection is improved, but power consumption and circuit area increase
Solution Approach 1:
The patent extracts the blocker rejection function from the main signal path by implementing a dedicated notch filter stage that specifically targets out-of-band blockers. This separate extraction allows the main receiver path to operate with lower power consumption while the notch filter handles blocker suppression independently.
Solution Approach 2:
The notch filter is positioned to operate before the main low-pass filter in the signal chain, performing preliminary blocker rejection. This preliminary action removes strong out-of-band blockers early, preventing them from overwhelming subsequent filtering stages and reducing the power required by downstream components.
2Object-affected harmful factors
If traditional high-order filters are used to eliminate out-of-band blockers, then blocker rejection is improved, but circuit area increases
Solution Approach 1:
The filtering function is segmented into two distinct stages: a notch filter for out-of-band blockers and a low-pass filter for in-band noise. This segmentation allows each filter to be optimized for its specific function with minimal circuit area, rather than using a single large high-order filter to handle all filtering requirements.
Solution Approach 2:
The receiver front-end architecture integrates multiple functions into a compact structure where the notch filter and low-pass filter work together in a unified signal path. The current-reuse architecture further enhances area efficiency by sharing current sources across multiple circuit blocks.
3Use of energy by moving object
If current-reuse architecture is used to reduce power consumption, then power efficiency is improved, but voltage headroom is reduced
Solution Approach 1:
The patent changes the operating parameters by using a higher supply voltage (2.5V) to compensate for the reduced voltage headroom in the current-reuse architecture. This parameter change allows the circuit to maintain adequate voltage margins across all stages while still achieving power savings through current reuse.
Solution Approach 2:
The current-reuse architecture copies and shares current sources across multiple circuit blocks (LNTA, mixer, and notch filter). By copying the current source functionality rather than using separate power supplies for each block, the overall power consumption is reduced while the shared current path is managed to maintain voltage headroom.
4Object-affected harmful factors
If notch filter is added to current-reuse architecture, then out-of-band blocker rejection is improved, but current consumption increases
Solution Approach 1:
The notch filter is merged with the current-reuse architecture by sharing the DC current source between the notch filter and the LNTA stage. This merging allows the notch filter to operate without requiring a completely separate power supply, thereby reducing the overall current consumption compared to having independent power sources for each block.
Solution Approach 2:
The notch filter stage is designed to be self-sufficient by using its own DC current source that is shared with other blocks. The current source automatically adjusts to provide the required bias current to the notch filter while also supplying current to the LNTA, creating a self-regulating power distribution system.
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 significantly reduces power consumption and maintains performance by sharing DC currents among components, enhancing energy efficiency and suitability for low-power applications like IoT devices.
Implementation Method 1
utilizing a passive mixer and operational transconductance amplifier (OTA) with an RC network for effective blocker attenuation
Implementation Method 2
A current-reuse receiver topology integrated with a current-mode notch filter that reuses supply currents from post-mixer and gain stages to power the low noise transconductance amplifier (LNTA) stage
Data Source
AI summary
Disclosed are example embodiments describing receiver circuits and methods for mitigating out-of-band blockers. The receiver circuits include a low noise transconductance amplifier (LNTA) stage, a down-conversion mixer stage, a post-mixer filter, and a gain stage. A feature is the reuse of supply currents from the post-mixer filter and the gain stage to supply the LNTA stage. The method involves down-converting an input signal, filtering the down converted signal through a current-mode notch filter, amplifying the filtered signal, and reusing a combined supply current for the LNTA stage.