CMOS Low-Noise Amplifier Using Digital Feedback Noise Reduction
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Solution Overview
Problem
CMOS low-noise amplification circuits face challenges in miniaturization due to the need for precise passive elements like inductors, which increase chip area and manufacturing time, and are difficult to digitally control, leading to high costs and complex re-design processes.
Innovation Solution
A digital low-noise amplification circuit that uses discretization, digital filtering, and negative feedback to select and control frequency bands without passive elements, converting continuous signals to discrete and back to continuous for feedback, allowing digital control of noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If spiral inductors are used for input matching and gain enhancement, then frequency characteristic and gain are improved, but chip area increases significantly
Solution Approach 1:
The patent extracts and removes the spiral inductor component from the circuit, replacing it with a digital signal processing approach. By taking out the passive inductor element that occupies large chip area, the invention achieves frequency selection and gain control through digital filtering algorithms instead of physical inductive components.
Solution Approach 2:
The patent substitutes the mechanical/electrical passive inductor system with a digital signal processing system. Instead of using physical inductors to achieve frequency characteristic and gain, the invention uses digital filtering and signal processing techniques that operate in the digital domain, eliminating the need for large-area passive components.
2Manufacturing precision
If multiple passive elements (inductors, capacitors) are used for frequency control, then frequency characteristic is improved, but manufacturing precision requirements increase and design time increases
Solution Approach 1:
The patent changes the control parameters from physical passive element values (inductance, capacitance) to digital signal processing parameters (filter coefficients, sampling frequency). By changing to digital parameters, the system achieves frequency control and gain adjustment through software algorithms rather than precise physical component manufacturing, dramatically reducing manufacturing precision requirements and design time.
Solution Approach 2:
The patent replaces the analog passive element system with a digital signal processing system. Instead of manually designing and tuning physical inductors and capacitors with high precision, the invention uses digital filtering algorithms that can be programmed and adjusted without physical re-manufacturing, eliminating iterative design cycles.
3Object-affected harmful factors
If analog feedback loops are used for noise reduction, then noise characteristic is improved, but device complexity and control difficulty increase
Solution Approach 1:
The patent substitutes the analog feedback loop with a digital feedback mechanism. Instead of using continuous analog circuits for noise reduction feedback, the invention samples the signal digitally and applies digital filtering and processing algorithms to reduce noise, then feeds back the processed digital signal. This approach reduces circuit complexity while maintaining noise reduction effectiveness.
Solution Approach 2:
The patent introduces a digital signal processing intermediary between the amplification stage and the feedback path. By inserting digital sampling, filtering, and processing stages as intermediaries, the system achieves noise reduction through algorithmic processing rather than complex analog circuitry, simplifying the overall device architecture.
4Reliability
If continuous-time analog processing is used, then signal fidelity is improved, but adaptability to different frequency bands decreases
Solution Approach 1:
The patent introduces dynamic reconfigurability through digital signal processing. By using digital filtering algorithms with adjustable parameters, the system can dynamically adapt to different frequency bands and signal characteristics without changing physical circuit components. The digital processing stage can be reprogrammed to maintain signal fidelity across various operating conditions and frequency ranges.
Solution Approach 2:
The patent creates a universal signal processing platform that can handle multiple frequency bands and signal types through a single digital processing architecture. Instead of designing separate analog circuits for each frequency band, the invention uses a unified digital signal processing approach that can be configured via software to process signals across different bands while maintaining high signal fidelity.
Data Source
AI summary
[Problems] to provide a CMOS low-noise amplification circuit which can reduce a chip area and design time, and which is easy to be digital-controlled from outside. [Means For Solving the Problems] The amplification circuit includes; an amplification stage (12) which amplifies an input signal up to an intended value; a sample and hold circuit (13) which samples the output signal from the amplification stage (12) by sampling the output signal with a sampling frequency which is at least twice the frequency band of the output signal to convert the output signal to a discrete time signal; a moving average calculation unit (15) which selects and outputs a particular frequency from the discrete time signal outputted from the sample and hold circuit (13) by a moving average operation; and a smoothing filter (17) which smoothes the output signal from the moving average calculation unit (15) and feed it back to the input of the amplification stage (12).