GaN FET Boost Converter Monolithic Integration for High Frequency

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Solution Overview

Problem

Conventional boost converters and current pulse generators face limitations in size reduction and pulse frequency due to the need for separate semiconductor dies for power transistors and gate drivers, and the switching speed limitations of silicon-based transistors, which restricts the miniaturization and high-frequency operation required for applications like lidar systems.

Innovation Solution

The integration of gallium nitride (GaN) FET transistor switches with monolithic gate drivers on a single semiconductor die, enabling higher switching speeds and reduced area for the boost converter circuit, allowing for increased pulse frequency and smaller form factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional vertical power MOSFETs are used in boost converters, then the circuit can be implemented with discrete components, but the device area increases and pulse frequency is limited due to separate semiconductor dies requirement

Engineering Contradiction:
Improvepulse frequencyVSAvoiddevice area
Core Design Contradiction:
SpeedVSArea of stationary object

Solution Approach 1:

The patent merges the power transistor and gate driver onto a single semiconductor die, eliminating the need for separate dies and interconnect structures. This integration directly reduces device area while enabling higher pulse frequencies through shorter signal paths and reduced parasitic inductance between the gate driver and power transistor.

Inventive Principle:
Principle #5Merging (Combining)

2Speed

If silicon-based transistors are used for switching, then the circuit can operate reliably, but the switching speed is limited which restricts pulse frequency

Engineering Contradiction:
Improveswitching speedVSAvoidoperational reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent changes the material parameter from silicon-based to gallium nitride (GaN) based transistors. This material substitution enables significantly higher switching speeds while maintaining operational reliability through GaN's superior breakdown voltage characteristics and higher electron saturation velocity, allowing the circuit to achieve higher pulse frequencies.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the capacitor is charged to higher voltage to generate high energy pulses, then the energy output increases, but the boost converter size and complexity increase

Engineering Contradiction:
Improveenergy outputVSAvoidconverter complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The integration of power and signal components on a single die simplifies the overall converter architecture by eliminating external interconnects and reducing the number of discrete components required. This merging approach enables high voltage operation with reduced complexity compared to conventional discrete implementations.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables higher pulsing frequencies and a smaller form factor for current pulse generators, improving the performance and compactness of systems like lidar by leveraging the high switching speeds and voltage handling capabilities of GaN FETs, while integrating power and signal components on a single die.

Implementation Method 1

the circuit, termed a boost converter, includes an inductor to store energy from the lower voltage power supply and transfers this energy to the capacitor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The integration of gallium nitride (GaN) FET transistor switches with monolithic gate drivers on a single semiconductor die, enabling higher switching speeds and reduced area for the boost converter circuit

Methodology Applied
Scientific EffectField effect transistor switching:

Data Source

PatentEP3824537B1Current pulse generator with integrated bus boost circuit
Publication Date: 2023.07.05 EFFICIENT POWER CONVERSION CORP
  • EP3824537B1 patent drawingFigure 1A~1B
  • EP3824537B1 patent drawingFigure 2
  • EP3824537B1 patent drawingFigure 3

AI summary

A current pulse generator circuit configured to be monolithically integrated into a single semiconductor die and provide high pulsing frequencies. A first GaN FET transistor controls the charging of a capacitor in a boost converter. A second GaN FET transistor controls the discharging of the capacitor through a load, such as a laser diode, connected to the boost converter. Both GaN FET transistors are preferably enhancement mode GaN FETs and may be integrated into the single semiconductor die, together with gate drivers. The diode in a conventional boost converter circuit can also be implemented in the present invention as a GaN FET transistor, and also integrated into the single semiconductor die.