Resonant Power FET Gate for Fast Switching With Lower Heat

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Solution Overview

Problem

Power FETs face limitations in switching high currents at high speeds due to increased heat generation and the need for thermal management, which complicates integration with computational semiconductor die and increases system costs, while existing methods do not sufficiently reduce ON-resistance or eliminate the need for solder joints in mobile platforms.

Innovation Solution

A resonant transistor gate with integrated passive circuit elements forms a lumped RLC circuit or distributed network within the gate structure, using high-density dielectric materials to tune resonant frequencies and reduce input capacitance, allowing for monolithic integration of power management modules with high-speed, high-current capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the transistor gate is made smaller to reduce gate capacitance and increase switching speed, then switching speed is improved, but heat generation increases due to higher current densities

Engineering Contradiction:
Improveswitching speedVSAvoidheat generation
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent changes the electrical parameters of the gate by introducing resonant circuit elements (inductors and capacitors) that transform the gate's impedance characteristics. This allows the gate to operate at resonant frequencies where current flow is optimized, reducing resistive losses and heat generation while maintaining high switching speeds. The resonant frequency is determined by the LC circuit parameters, enabling speed control without simply reducing gate size.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent makes the gate structure dynamically responsive by incorporating tunable reactive elements that can be adjusted to match different operating frequencies. This dynamic adaptation allows the gate to maintain optimal performance across varying conditions, achieving high switching speeds only when needed while reducing heat generation during normal operation through resonant impedance matching.

Inventive Principle:
Principle #15Dynamics

2Power

If higher current levels are used to achieve high currents at high switching speeds, then current output is improved, but thermal management complexity increases

Engineering Contradiction:
Improvecurrent outputVSAvoidthermal management complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent converts the harmful effect of high current flow into a beneficial resonant phenomenon. By designing the gate as an LC resonant circuit, the high currents needed for power output flow through reactive elements that store and release energy cyclically, reducing resistive heating. The resonant current amplification achieves high power output without proportionally increasing heat generation, thereby simplifying thermal management requirements.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent employs periodic current flow characteristic of resonant circuits, where current oscillates at the resonant frequency. This periodic action allows energy to be delivered in controlled pulses rather than continuous high current, reducing average power dissipation and heat generation while maintaining peak current capability for high power output when needed.

Inventive Principle:
Principle #19Periodic action

3Speed

If discrete components are used to achieve high switching speeds, then switching performance is improved, but integration with computational die becomes difficult

Engineering Contradiction:
Improveswitching performanceVSAvoidintegration difficulty
Core Design Contradiction:
SpeedVSEase of manufacture

Solution Approach 1:

The patent merges the discrete resonant circuit elements (inductors and capacitors) directly into the transistor gate structure, creating an integrated resonant gate device. This combination eliminates the need for separate discrete components while maintaining the resonant switching performance. The inductive and capacitive elements are formed as part of the gate electrode and insulation structure, enabling monolithic integration with computational die and simplifying manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

4Power

If the gate electrode is made larger to reduce ON-resistance, then current handling capability is improved, but gate capacitance increases reducing switching speed

Engineering Contradiction:
Improvecurrent handling capabilityVSAvoidswitching speed
Core Design Contradiction:
PowerVSSpeed

Solution Approach 1:

The patent changes the electrical parameters of the gate by introducing resonant circuit elements (inductors and capacitors) that transform the gate's impedance characteristics. This allows the gate to operate at resonant frequencies where current flow is optimized, reducing resistive losses and heat generation while maintaining high switching speeds. The resonant frequency is determined by the LC circuit parameters, enabling speed control without simply reducing gate size.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables efficient power management with reduced thermal management needs, lower ON-resistance, and the elimination of solder joints, enhancing the operational efficiency and reliability of power FETs in high-speed applications.

Implementation Method 1

the resonant gate is electromagnetically resonant at one or more predetermined frequencies

Methodology Applied
Scientific EffectElectromagnetic resonance: Resonance

Implementation Method 2

using high-density dielectric materials to tune resonant frequencies and reduce input capacitance

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2609626B1Power FET with a resonant transistor gate
Publication Date: 2024.04.03 DE ROCHEMONT L PIERRE
  • EP2609626B1 patent drawingFigure 1A
  • EP2609626B1 patent drawingFigure 1B
  • EP2609626B1 patent drawingFigure 1C

AI summary

A semiconductor FET provides a resonant gate and source and drain electrodes, wherein the resonant gate is electromagnetically resonant at one or more predetermined frequencies.