Cross-Coupled Inductor Noise-Cancellation Amplifier Layout
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Solution Overview
Problem
Conventional noise-cancellation amplifiers require bulky components like resistors and capacitors for noise cancellation, leading to increased area, complexity, and process variation, which complicates layout and increases cost.
Innovation Solution
The use of cross-coupled inductors replaces capacitors and resistors, simplifying the layout and reducing the number of components, allowing for a more symmetrical and stable noise-cancellation amplifier design with fewer on-chip components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional noise-cancellation amplifiers use resistors and capacitors for noise cancellation, then noise cancellation function is achieved, but device area increases and layout complexity increases
Solution Approach 1:
The patent changes the fundamental parameters of the noise cancellation circuit by replacing resistors and capacitors with inductors. This parameter substitution enables the same noise cancellation function to be achieved with a different component topology that occupies less area. The inductor-based differential pair configuration provides noise cancellation through inductive coupling rather than RC time constants, fundamentally changing how the noise cancellation function is implemented physically.
Solution Approach 2:
The patent extracts and eliminates unnecessary components (resistors and capacitors) from the conventional noise cancellation amplifier architecture. By removing these bulky passive components and replacing them with a more compact inductor-based differential structure, the design achieves noise cancellation without the area penalty of traditional RC-based noise cancellation circuits.
2Reliability
If conventional noise-cancellation amplifiers use resistors and capacitors, then noise cancellation is achieved, but device complexity increases
Solution Approach 1:
The patent merges the noise cancellation function with the signal amplification function into a unified inductor-based differential pair structure. Instead of having separate RC noise cancellation circuits alongside the amplifier, the inductors are integrated directly into the amplifier core, combining multiple functions into a single compact structure that reduces overall device complexity.
Solution Approach 2:
The patent extracts and removes resistors and capacitors from the circuit architecture, reducing the total component count. The noise cancellation function is maintained through the inductive coupling in the differential pair, eliminating the need for separate RC components and thereby simplifying the overall device structure.
3Reliability
If conventional noise-cancellation amplifiers use resistors and capacitors, then noise cancellation is achieved, but layout simplification is prevented
Solution Approach 1:
The patent merges the noise cancellation functionality into the core amplifier structure using inductors that are part of the differential pair configuration. This integration eliminates the need for separate noise cancellation circuits, allowing for a more unified and simplified layout where noise cancellation and signal amplification share the same structural elements.
4Reliability
If conventional noise-cancellation amplifiers use resistors and capacitors, then noise cancellation is achieved, but manufacturing precision requirements increase due to production variances
Solution Approach 1:
The patent employs a symmetric differential pair structure with matched inductors, which inherently provides immunity to production variances. The symmetric topology ensures that process variations affect both sides equally, causing common-mode errors that cancel out. This symmetry principle makes the design more robust to manufacturing tolerances compared to asymmetric RC-based approaches.
Solution Approach 2:
The patent converts the potential harm of production variances into a benefit through the differential structure. By using matched inductors in a symmetric configuration, process variations that would normally degrade performance instead create common-mode signals that are rejected by the differential architecture, thereby improving immunity to manufacturing tolerances.
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 reduces layout complexity, minimizes process variation, and achieves efficient noise cancellation with a smaller footprint, lower cost, and improved performance by eliminating the need for bulky components.
Implementation Method 1
the first inductor system is inductively coupled with the second inductor system and the second inductor system is inductively coupled with the third inductor system
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Described is a noise-cancellation amplifier (200), comprising a first inductor system with a first inductor (L1) and a second inductor (L2); a second inductor system with a third inductor (L3) and a fourth inductor (L4); a first transistor (T1) being coupled with the third inductor (L3); a second transistor (T2) being coupled with the fourth inductor (L4); and a third inductor system with a fifth inductor (L5) and a sixth inductor (L6), the fifth inductor (L5) being coupled with a gate of the first transistor (T1) and the sixth inductor (L6) being coupled with a gate of the second transistor (T2); wherein the first inductor system is inductively coupled with the second inductor system and the second inductor system is inductively coupled with the third inductor system. In this way, a noise cancellation effect of the noise cancellation amplifier (200) may be improved.