Single-Ended LNA Circuit With Active Balun Differential Output
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Solution Overview
Problem
Multi-mode and multi-band transceivers face challenges with single-ended Low Noise Amplifiers (LNAs) due to increased second-order nonlinearity and complex mixer calibration, which can lead to noise suppression issues and bulky components.
Innovation Solution
A single-ended low noise amplifier with integrated active balun functionality is used to generate a differential output, reducing second-order nonlinearity and minimizing additional noise, achieved through a cascaded amplification stage configuration with push-pull and cascoding circuits, utilizing complementary MOSFETs to maintain low noise figure and current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If single-ended LNAs are used in multi-mode and multi-band transceivers, then input ball count and chip area are reduced, but second-order nonlinearity increases and mixer calibration becomes complex
Solution Approach 1:
The patent combines the single-ended LNA with an active balun circuit into a single integrated amplifier that directly outputs differential signals. This merging eliminates the need for separate passive transformers and additional amplification branches, reducing chip area while maintaining low second-order nonlinearity through the active differential generation mechanism.
Solution Approach 2:
The patent replaces the traditional passive transformer-based differential signal generation with an active electronic circuit using MOSFETs. This substitution eliminates bulky passive components and enables direct differential output generation, reducing both area and improving linearity by avoiding the nonlinear characteristics of passive transformers.
2Ease of operation
If single-ended LNAs with passive transformers are used, then differential output is achieved, but device area increases due to bulky passive components
Solution Approach 1:
The patent replaces the mechanical/passive transformer system with an active electronic differential generation circuit using MOSFETs. This active circuit generates differential outputs directly through electronic signal processing, eliminating the need for bulky passive transformers and reducing overall device area while maintaining differential output capability.
Solution Approach 2:
The patent creates a universal amplifier circuit that can handle single-ended inputs and generate differential outputs without requiring separate dedicated components for each function. The active balun integrated into the LNA performs multiple functions (amplification, differential conversion, impedance matching) in a single compact circuit, reducing total device area.
3Object-generated harmful factors
If fully differential LNAs are used, then second-order nonlinearity is reduced, but current consumption and chip area increase
Solution Approach 1:
The patent merges the differential signal generation function into the LNA itself through an active balun circuit, eliminating the need for separate additional amplification branches. This integration achieves low second-order nonlinearity comparable to fully differential LNAs while reducing current consumption by sharing circuit resources and eliminating redundant components.
Solution Approach 2:
The patent uses a single-ended input signal to generate a differential output by creating a complementary signal path using MOSFETs. Instead of requiring two independent fully differential input paths, the circuit copies and inverts the single-ended signal to create the differential output, reducing current consumption while maintaining low nonlinearity characteristics.
Data Source
AI summary
Embodiments provide an amplification circuit, an apparatus for amplifying, a low noise amplifier, a radio receiver, a mobile terminal, a base station, and a method for amplifying. An amplification circuit (10) for amplifying a radio signal comprises a first amplification stage (12) configured to amplify an input signal, Vin(t), to obtain an intermediate signal. The amplification circuit (10) further comprises a cascoding circuit (14) configured to amplify the intermediate signal to obtain a first output signal Voutn(t). The amplification circuit (10) further comprises a second amplification stage (16) configured to amplify the intermediate signal to obtain a second output signal, Voutp(t).