Isolated Gate Driver Feedback Acquisition Across an Isolation Barrier

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Solution Overview

Problem

Existing isolated gate driver devices face challenges with integration in limited spaces, reliability during switching operations, high current consumption due to fast communication protocols, potential noise immunity issues with short ADC conversion times, and limited switching frequency, which affects real-time feedback signal acquisition and diagnostic capabilities.

Innovation Solution

The proposed isolated gate driver device employs a half-duplex communication channel through capacitive coupling between low-voltage and high-voltage sections, utilizing a question-and-answer mechanism with priority management to prevent conflicts, and an ADC with a 10 μs conversion time to ensure noise-free acquisition, along with accumulator blocks for data integrity and asynchronous operation, allowing on-demand conversions and higher switching frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a fast communication protocol is used between low-voltage and high-voltage sections, then data transfer speed is improved, but current consumption increases

Engineering Contradiction:

Improvedata transfer speedVSAvoidcurrent consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The communication channel operates in periodic half-duplex mode, alternating between transmission and reception phases. This periodic operation allows the system to achieve necessary data transfer speeds while reducing average current consumption compared to continuous high-speed communication protocols.

Inventive Principle:

Principle #19Periodic action

2Speed

If ADC conversion time is reduced for real-time feedback, then response speed is improved, but noise immunity deteriorates

Engineering Contradiction:

Improveresponse speedVSAvoidnoise immunity

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The ADC conversion time is set to 10 μs, which is longer than the minimum required for real-time feedback. This excessive conversion time provides sufficient noise immunity while still meeting real-time control requirements by capturing feedback signals at appropriate intervals during the switching cycle.

Inventive Principle:

Principle #16Partial or excessive action

3Area of stationary object

If integration is increased to reduce area occupation, then device compactness is improved, but reliability during switching operations may deteriorate

Engineering Contradiction:

Improvearea occupationVSAvoidreliability during switching operations

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The gate driver device is segmented into distinct low-voltage and high-voltage sections with galvanic isolation between them. This segmentation allows compact integration while maintaining reliability by electrically separating the control circuitry from the high-power switching operations, preventing noise and voltage spikes from affecting the control section.

Inventive Principle:

Principle #1Segmentation

4Productivity

If switching frequency is increased for higher productivity, then power conversion efficiency is improved, but feedback signal acquisition reliability deteriorates

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidfeedback signal acquisition reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary actions by using accumulator blocks to store and manage feedback data before it is needed for control decisions. This allows the feedback acquisition system to operate reliably at lower effective rates while supporting higher switching frequencies, as the accumulators buffer data to ensure no information is lost during high-speed operation.

Inventive Principle:

Principle #10Preliminary action

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 real-time, noise-immune feedback signal acquisition, efficient data transfer, and diagnostic capabilities within a compact, integrated design, supporting higher switching frequencies and reducing data loss, while minimizing area occupation and external device requirements.

Implementation Method 1

a communication channel (15), configured to provide a half-duplex type communication through capacitive coupling between the low-voltage and high-voltage sections (10a, 10b)

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS12191850B2Isolated gate driver device for a power electrical system and corresponding power electrical system

Publication Date: 2025.01.07 STMICROELECTRONICS SRL

AI summary

In an embodiment a method includes receiving, at an input of a low-voltage section of a gate driver, a PWM control signal with a switching frequency, providing, at an output of a high-voltage section of the gat driver, a gate-driving signal as a function of the PWM control signal to a power stage, wherein the high-voltage section is galvanically isolated from the low-voltage section, receiving, at a feedback input of the high-voltage section, at least one feedback signal indicative of an operation of the power stage, converting, at an ADC module of the high-voltage section, the feedback signal into a digital data stream, providing, to the ADC module, a conversion-trigger signal designed to determine a start of a conversion for acquiring a new sample of the feedback signal and sending, via an isolation communication channel between the low-voltage section and the high-voltage section, the digital data stream to the low-voltage section.