Broadband Amplifier Circuit With Current Mirror Gain and Stability
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Solution Overview
Problem
Designing broadband amplifiers that maintain stability while increasing gain is challenging due to the trade-off between gain and phase margin, particularly in 5G communication systems operating at higher frequency bands.
Innovation Solution
The proposed amplification circuit structure includes a main amplifying unit with separate paths for higher gain and broadband characteristics, utilizing a current mirror to increase overall gain and a common-mode feedback unit for stability, allowing independent control of currents and parasitic pole management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gain of a broadband amplifier is increased to reduce gain variation under PVT conditions, then the feedback gain approaches 1/f and accurate feedback is obtained, but the phase margin is reduced and stability is lowered
Solution Approach 1:
The amplifier is divided into multiple independent gain stages (first amplifying stage, second amplifying stage, third amplifying stage) with separate gain control. This segmentation allows each stage to contribute to the overall gain while maintaining individual stability characteristics, preventing the phase margin degradation that would occur in a single high-gain stage.
Solution Approach 2:
The patent employs multiple feedback paths including a first feedback path from the first amplifying stage, a second feedback path from the second amplifying stage, and a third feedback path from the third amplifying stage. These distributed feedback mechanisms maintain accuracy while preserving stability by providing local compensation at each stage rather than relying on a single high-gain feedback loop.
2Measurement precision
If the gain is increased in a broadband amplifier, then accurate feedback is obtained, but the bandwidth-gain trade-off reduces phase margin
Solution Approach 1:
The total gain is distributed across three separate amplifying stages, each with moderate gain. This segmentation allows the amplifier to achieve high overall gain while each individual stage maintains adequate phase margin, thus preserving bandwidth and stability characteristics.
Solution Approach 2:
The patent uses variable gain control for each amplifying stage, allowing dynamic adjustment of gain distribution. This enables optimization of the gain-bandwidth product across different operating conditions, maintaining phase margin while achieving required feedback precision.
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AI summary
The apparatus relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long-Term Evolution (LTE). The disclosure relates to an apparatus including an electronic circuit for amplifying a signal. The apparatus includes a transceiver including an amplification circuit, and at least one processor coupled to the transceiver. The amplification circuit includes a first path to generate a first current corresponding to a voltage of an input signal, a second path to generate a second current corresponding to a voltage of the input signal, a separation unit to control each of the first current and the second current, a current mirror to generate a third current corresponding to the first current, and a folding unit to generate an output signal on the basis of the second current and the third current.