Variable-Gain Cascode Amplifier With Phase Compensation

Solution Overview

Problem

Existing variable-gain amplifiers suffer from large phase changes, leading to increased layout size and power consumption, which adversely affect beam scanning and beam forming precision.

Innovation Solution

A low-phase-shift variable-gain amplifier design incorporating a differential cascode amplification circuit with a common-source and common-gate transistor, a current-steering structure, and a phase compensation circuit with a variable capacitor to reduce phase shift fluctuations during gain changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a two-stage structure with inverting compensation circuit is used to reduce phase shift, then phase fluctuation is reduced, but layout area and power consumption increase

Engineering Contradiction:

Improvephase shift control precisionVSAvoidlayout area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent divides the compensation function into two independent parts: a fixed compensation capacitor connected to the first-stage amplifier and a variable compensation capacitor connected to the second-stage amplifier. This segmentation allows each capacitor to handle specific compensation tasks, achieving effective phase shift reduction without requiring a complex two-stage cascade structure, thereby reducing layout area while maintaining precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a variable compensation capacitor that can be dynamically adjusted based on gain settings. This dynamic element adapts to different operating conditions, providing optimal phase compensation across various gain levels without requiring additional fixed compensation circuits, thus reducing overall layout area while maintaining precision.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If a two-stage structure with inverting compensation circuit is used to reduce phase shift, then phase fluctuation is reduced, but power consumption increases

Engineering Contradiction:

Improvephase shift control precisionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

The patent divides the compensation function into two independent parts: a fixed compensation capacitor connected to the first-stage amplifier and a variable compensation capacitor connected to the second-stage amplifier. This segmentation allows each capacitor to handle specific compensation tasks, achieving effective phase shift reduction without requiring a complex two-stage cascade structure, thereby reducing layout area while maintaining precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a variable compensation capacitor that can be dynamically adjusted based on gain settings. This dynamic element adapts to different operating conditions, providing optimal phase compensation across various gain levels without requiring additional fixed compensation circuits, thus reducing overall layout area while maintaining precision.

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If an inductor is connected in series to reduce phase shift, then phase shift is reduced, but layout area increases

Engineering Contradiction:

Improvephase shiftVSAvoidlayout area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent replaces the traditional inductor-based phase compensation approach with a capacitor-based compensation circuit. This substitution eliminates the need for large inductors that occupy significant layout area, while achieving the same phase shift reduction effect through capacitive compensation, thereby significantly reducing layout area while maintaining precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12519434B2Low-phase-shift variable-gain amplifier and method for processing radio frequency signal

Publication Date: 2026.01.06 SANECHIPS TECH CO LTD

AI summary

Provided are a low-phase-shift variable-gain amplifier and a method for processing a radio frequency signal. The low-phase-shift variable-gain amplifier comprises: a differential cascode amplification circuit, which comprises a common-source transistor and a common-gate transistor, wherein a gate stage of the common-source transistor is connected to a first bias voltage via a target resistor, and a gate stage of the common-gate transistor is connected to a second bias voltage; a current-steering structure, wherein one end of the current-steering structure is connected between the common-source transistor and the common-gate transistor, a third current signal outputted by the current-steering structure is used to adjust a gain of the differential cascode amplification circuit; and a phase compensation circuit, wherein one end of the phase compensation circuit is connected between the common-source transistor and the common-gate transistor.