GaN High-Side Driver Voltage Boosting With Bootstrap Charge Pump

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Solution Overview

Problem

High-side integrated driver circuits using GaN HEMTs face challenges in minimizing static current and power consumption due to the use of depletion mode HEMTs, which operate with zero gate voltage, leading to increased power consumption and potential damage to electrical components.

Innovation Solution

Implementing a combination of enhancement mode HEMTs and depletion mode HEMTs with bootstrap circuits and charge pump circuits to generate overdrive voltage, minimizing static current and optimizing power delivery by using a multistage E-HEMT device configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If depletion mode HEMTs are used to enable high-power throughput, then power delivery capability is improved, but static current increases leading to higher power consumption

Engineering Contradiction:

Improvepower throughputVSAvoidpower consumption

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The driver circuit is divided into multiple voltage stages (first voltage stage, second voltage stage, third voltage stage) with different HEMT types. Depletion mode HEMTs are used in higher voltage stages where high power throughput is needed, while enhancement mode HEMTs are used in lower voltage stages where static current minimization is critical. This segmentation allows each stage to be optimized for its specific function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the driver circuit are assigned different HEMT types based on local requirements. The first voltage stage uses enhancement mode HEMTs for low static current, the second voltage stage uses depletion mode HEMTs for high power delivery, and the third voltage stage uses enhancement mode HEMTs for final voltage boosting. Each local region has optimized quality characteristics for its specific function.

Inventive Principle:

Principle #3Local quality

2Device complexity

If depletion mode HEMTs operate with zero gate voltage, then device simplicity is improved, but power consumption increases and component damage risk increases

Engineering Contradiction:

Improvedevice simplicityVSAvoidcomponent damage

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

Bootstrap circuits and charge pump circuits are used to pre-charge capacitors and generate overdrive voltage before the depletion mode HEMTs are activated. This preliminary action ensures that when depletion mode HEMTs switch on, they do so with sufficient voltage margin, preventing static current flow and potential component damage while maintaining operational simplicity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Bootstrap capacitors and charge pump circuits act as intermediary elements between the control logic and the depletion mode HEMTs. These intermediaries generate the necessary overdrive voltage to ensure proper switching operation, protecting the depletion mode HEMTs from operating in their dangerous zero-gate-voltage region while maintaining the simplicity of depletion mode device operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If enhancement mode HEMTs are used to minimize static current, then power consumption is reduced, but voltage boosting capability is limited

Engineering Contradiction:

Improvepower consumptionVSAvoidvoltage boosting

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

The patent combines enhancement mode HEMTs and depletion mode HEMTs in a multi-stage configuration. Enhancement mode HEMTs are used in stages where low static current is prioritized, while depletion mode HEMTs are used in stages where high voltage boosting and power delivery are needed. The merging of these two HEMT types allows the system to achieve both low power consumption and high voltage boosting capability simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The driver circuit dynamically switches between different HEMT types and operating modes across multiple voltage stages. The bootstrap circuits and charge pump circuits dynamically generate overdrive voltage that adapts to the switching requirements of each stage, allowing enhancement mode HEMTs to operate efficiently in low-power stages while depletion mode HEMTs provide dynamic high-power boosting when needed.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12574029B2Generating high dynamic voltage boost

Publication Date: 2026.03.10 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Devices, systems, and methods are provided for generating a high, dynamic voltage boost. An integrated circuit (IC) includes a driving circuit having a first stage and a second stage. The driving circuit is configured to provide an overdrive voltage. The IC also includes a charge pump circuit coupled between the first stage and the second stage. The charge pump circuit is configured generate a dynamic voltage greater than the overdrive voltage. The IC also includes a bootstrap circuit coupled to the charge pump circuit, configured to further dynamically boost the overdrive voltage of the driving circuit.