Incremental Gain Amplifier With Discrete Paths for Low-Distortion Control
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Solution Overview
Problem
Existing variable-gain amplifiers suffer from noise and distortion due to analog variable-gain elements, which limit their performance in signal processing applications, especially when multiple overlapping elements are used, introducing partition noise and nonlinearities that affect the dynamic range and frequency spectrum of the output signal.
Innovation Solution
The implementation of an incremental gain amplifier with multiple selectable signal paths and digital or analog gain control interfaces, which allows for discrete gain settings by sequentially switching signal paths or using switchable transistor pairs, eliminating the need for analog variable-gain elements and reducing noise and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If analog variable-gain elements are used to provide continuous gain adjustment, then gain control flexibility is improved, but noise and distortion increase
Solution Approach 1:
The amplifier is divided into multiple discrete gain stages, each with a fixed gain value. Instead of using a single analog variable-gain element, the circuit segments the gain control into separate functional blocks (first amplifier stage, second amplifier stage, third amplifier stage) where each stage contributes a specific gain factor. This segmentation allows digital selection of gain values while avoiding the noise and distortion associated with continuous analog adjustment.
Solution Approach 2:
The patent implements dynamic gain control through digital switching mechanisms that selectively enable or disable specific amplifier stages based on the desired gain setting. Control logic dynamically configures which stages are active, allowing the overall gain to be adjusted in discrete steps without using analog variable-gain elements. This dynamic reconfiguration maintains signal integrity while providing flexible gain control.
2Adaptability or versatility
If multiple overlapping variable-gain elements are used to expand gain range, then gain adjustment range is improved, but partition noise and nonlinearities increase
Solution Approach 1:
The amplifier chain is segmented into distinct non-overlapping stages, each with a defined gain contribution. The first amplifier stage provides initial amplification, the second stage provides additional gain, and the third stage provides final amplification. By segmenting the gain function into separate stages rather than using overlapping variable-gain elements, the patent eliminates partition noise while achieving a wide overall gain range through the combination of discrete stage gains.
Solution Approach 2:
The patent merges multiple fixed-gain amplifier stages in series to achieve the overall gain function. Instead of using multiple overlapping variable-gain elements that create partition noise, the circuit combines discrete amplifier stages where the total gain is the product of individual stage gains. This merging approach maintains linearity and reduces noise while providing the required gain adjustment range through digital selection of stage configurations.
3Object-generated harmful factors
If discrete gain settings are implemented by switching signal paths, then noise and distortion are reduced, but device complexity increases
Solution Approach 1:
The control function is segmented into independent control logic blocks that manage each amplifier stage separately. Rather than using a single complex switching mechanism, the patent divides the control function into manageable segments that can independently enable or disable specific stages. This segmentation simplifies the overall control architecture while achieving discrete gain settings through coordinated stage activation.
Solution Approach 2:
The control logic is designed to automatically configure the amplifier stages based on the desired gain setting without requiring external intervention or complex switching control. The system self-manages the activation and deactivation of amplifier stages through integrated control mechanisms, reducing the overall device complexity while maintaining precise discrete gain control. The control logic adapts the circuit configuration autonomously based on operational requirements.
Data Source
AI summary
An amplifier includes an amplifier section having selectable signal paths to provide discrete gain settings, and logic to incrementally select the signal paths. The logic may be configured to increment the gain in response to digital gain control signals or an analog gain control signal. Another amplifier has an input section with one or more input cells and an output section with one or more output cells. Either the input section or the output section includes at least two cells that may be selected to provide discrete gain settings. A loop amplifier is configured in a feedback arrangement with the input section. The input and output sections may have multiple selectable cells to provide coarse and fine gain steps. The gain of the loop amplifier may be coordinated with the gain of the input section to provide constant bandwidth operation.