High-Side Gate Drive Path With Variable Resistance for Fast Switching

Solution Overview

Problem

The use of a single fixed-value resistor between a bootstrap capacitor and the gate of a high-side switch in an inverter compromises the performance by creating a design contradiction between reducing leakage current and improving rise time of the gate drive signal.

Innovation Solution

Implementing a variable-resistive gate drive path using a depletion mode transistor and a resistor, or a controllable switch in series or parallel configuration, to dynamically adjust resistance based on logic signals, thereby controlling leakage current and rise time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a large resistance value is used between the bootstrap capacitor and the gate of the high-side switch, then the leakage current is reduced, but the rise time of the gate drive signal increases

Engineering Contradiction:

Improveleakage currentVSAvoidrise time of gate drive signal

Core Design Contradiction:

Loss of energyVSSpeed

Solution Approach 1:

The patent applies the Dynamics principle by making the resistance value variable rather than fixed. A control switch is introduced that dynamically changes the resistance between the bootstrap capacitor and the gate of the high-side switch based on the state of the low-side switch. When the low-side switch is off, the control switch connects a smaller resistance to reduce rise time. When the low-side switch is on, the control switch connects a larger resistance to reduce leakage current. This dynamic adjustment resolves the contradiction between minimizing leakage current and achieving fast rise time.

Inventive Principle:

Principle #15Dynamics

2Speed

If a small resistance value is used between the bootstrap capacitor and the gate of the high-side switch, then the rise time of the gate drive signal is improved, but the leakage current increases

Engineering Contradiction:

Improverise time of gate drive signalVSAvoidleakage current

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The patent applies the Dynamics principle by making the resistance value variable rather than fixed. A control switch is introduced that dynamically changes the resistance between the bootstrap capacitor and the gate of the high-side switch based on the state of the low-side switch. When the low-side switch is off, the control switch connects a smaller resistance to reduce rise time. When the low-side switch is on, the control switch connects a larger resistance to reduce leakage current. This dynamic adjustment resolves the contradiction between minimizing leakage current and achieving fast rise time.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12525977B2Gate drive apparatus and control method

Publication Date: 2026.01.13 DIODES INC

AI summary

An apparatus includes a capacitive device configured to provide bias power for a high-side switch, a gate drive path connected between the capacitive device and a gate of the high-side switch, wherein the gate drive path comprises a controllable switch and a first resistive device coupled in parallel between the capacitive device and the gate of the high-side switch, and a control switch connected between the gate of the high-side switch and ground.