Variable Gain Phase Shifter Circuit Design
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Solution Overview
Problem
Conventional variable gain phase shifters face challenges in independently controlling phase and gain due to separate design of phase shift and gain adjustment blocks, leading to increased circuit size and complexity.
Innovation Solution
A variable gain phase shifter incorporating an in-phase/quadrature (I/Q) generator and a vector summation circuit that adjusts both phase and gain simultaneously using a single block, with a digital-to-analog converter generating current control signals to manage vector magnitudes and directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If phase shift block and gain adjustment block are designed separately, then phase and gain can be adjusted independently, but circuit size and complexity increase
Solution Approach 1:
The patent combines the phase shift block and gain adjustment block into a single integrated variable gain phase shifter. The phase shift unit and gain adjustment unit share common circuit resources such as the I/Q generator, vector summation circuit, and current control circuits, allowing both phase and gain to be adjusted independently through separate control signals while reducing overall circuit complexity and size.
Solution Approach 2:
The integrated circuit performs multiple functions simultaneously: the I/Q generator produces both in-phase and quadrature signals for phase control, while the vector summation circuit with current-controlled current sources provides both phase shifting and gain adjustment capabilities. This multi-functional design eliminates the need for separate dedicated circuits for each function.
2Ease of operation
If conventional VGA or attenuator is used for gain adjustment, then gain can be adjusted, but circuit size increases
Solution Approach 1:
The gain adjustment unit is integrated with the phase shift unit by sharing the vector summation circuit and current control infrastructure. The current-controlled current sources use the same I/Q signals and vector summation architecture as the phase shift function, allowing gain adjustment without requiring a separate VGA or attenuator circuit.
3Ease of operation
If separate phase shift and gain adjustment blocks are used, then independent control is possible, but manufacturing cost increases
Solution Approach 1:
By integrating multiple functions into a single circuit block with shared components (I/Q generator, vector summation circuit, current control circuits), the patent reduces the total component count and circuit area, leading to lower manufacturing costs while maintaining independent phase and gain control capabilities.
4Device complexity
If integrated variable gain phase shifter is used, then circuit size is reduced, but control precision may be compromised
Solution Approach 1:
The integrated circuit maintains precise control by segmenting the control functions: separate control signals independently regulate the phase shift unit and gain adjustment unit. The vector summation circuit with current-controlled current sources provides fine-grained control over signal vectors, enabling high-precision phase and gain adjustment despite the integrated architecture.
Solution Approach 2:
The patent employs digital-to-analog converters and current control circuits that provide precise control mechanisms, allowing accurate adjustment of phase and gain parameters. The structured control architecture ensures that integration does not compromise control precision.
Data Source
AI summary
A variable gain phase shifter includes an I/Q generator and a vector summation circuit. The I/Q generator generates phase signals based on an input signal. The vector summation circuit adjusts magnitudes and directions of first, second, third and fourth in-phase vectors and first, second, third and fourth quadrature vectors, and generates an output signal by summing the in-phase vectors and the quadrature vectors, based on the phase signals, selection signals and current control signals. The vector summation circuit includes first, second, third and fourth vector summation cells and first, second, third and fourth current control circuits. The first and second vector summation cells adjust the directions of the first and second in-phase vectors and the first and second quadrature vectors. The third and fourth vector summation cells adjust the directions of the third and fourth in-phase vectors and the third and fourth quadrature vectors. The first and second current control circuits are connected to the first and second vector summation cells, and adjust an amount of a first current and an amount of a second current. The third and fourth current control circuits are connected to the third and fourth vector summation cells, and adjust an amount of a third current and an amount of a fourth current.