RF Doubler and Tripler Feedback Balancing Without PLLs

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Solution Overview

Problem

Existing radio frequency doublers and triplers face inefficiencies and complexity in achieving frequency doubling and tripling, often requiring bulky filters and phase-locked loops, which are impractical at high frequencies.

Innovation Solution

A radio frequency doubler and tripler design utilizing a feedback loop to balance differential outputs, eliminating the need for phase-locked loops and bulky filters by controlling DC components to achieve frequency doubling and tripling without phase shifts, using transistors and capacitors to manage alternating and direct current components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If phase-locked loops and bulky filters are used to achieve frequency doubling and tripling, then frequency multiplication is achieved, but device complexity and power losses increase

Engineering Contradiction:
Improvefrequency multiplication capabilityVSAvoidcircuit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the phase-locked loop and bulky filter components from the frequency multiplication circuit, achieving frequency doubling and tripling through a simplified transistor-based architecture that directly processes differential signals without requiring these traditional auxiliary components

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/physical filtering approach with an electronic feedback control mechanism using transistors and operational amplifiers, substituting bulky passive filters with active electronic components that achieve the same frequency selection function with reduced size and complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If phase-locked loops are used to achieve frequency multiplication, then frequency stability is improved, but locking range becomes narrow

Engineering Contradiction:
Improvefrequency stabilityVSAvoidlocking range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic feedback control through operational amplifiers that continuously monitor and adjust the differential output signals, enabling the circuit to adapt to a wide range of input frequencies and maintain stability without being constrained to a narrow locking range like traditional phase-locked loops

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback loops that sense the differential output signals and use operational amplifiers to regulate the transistor operating points, ensuring frequency stability through continuous correction while maintaining broad adaptability to different input conditions

Inventive Principle:
Principle #23Feedback

3Measurement precision

If bulky filters are used for frequency multiplication, then frequency selectivity is improved, but device volume increases

Engineering Contradiction:
Improvefrequency selectivityVSAvoidcircuit volume
Core Design Contradiction:
Measurement precisionVSVolume of stationary object

Solution Approach 1:

The patent changes the operating parameters of the transistors through feedback control, dynamically adjusting their electrical characteristics to achieve sharp frequency selectivity without requiring physically large filter components, thereby maintaining high frequency precision in a compact form factor

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes physical filtering mechanisms with electronic feedback control, replacing bulky mechanical filters with compact electronic circuits that achieve equivalent or superior frequency selectivity through active signal regulation rather than passive frequency rejection

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If traditional frequency doubling circuits are used, then frequency multiplication is achieved, but power losses increase

Engineering Contradiction:
Improvefrequency doubling efficiencyVSAvoidpower loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent implements self-balancing through feedback loops where the operational amplifiers automatically adjust the transistor operating points to optimize efficiency, enabling the circuit to maintain high frequency doubling performance with minimal power loss through autonomous regulation rather than requiring external power compensation

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4142149B1Radio frequency doubler and tripler
Publication Date: 2026.04.22 STMICROELECTRONICS FRANCE
  • EP4142149B1 patent drawingFigure 1~2
  • EP4142149B1 patent drawingFigure 3~4
  • EP4142149B1 patent drawingFigure 5~6

AI summary

The present description relates to a radio frequency doubler (1) comprising: a first transistor (T1) and a second transistor (T2) connected in parallel between a first differential output (OUT2+) and a current source (100); a third transistor (T3) connected between the current source (100) and a second differential output (OUT2-); a circuit (106) applying a first DC voltage to the gate of the first transistor (T1) and to the gate of the second transistor (T2), and a second DC voltage (Vbias) to the gate of the third transistor (T3); and a feedback loop (108) controlling the first or second voltage from a difference between the DC components of the differential outputs (OUT2+, OUT2-).