Integrated Gate Clamp Circuit for Power Module Parasitic Turn-On

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Solution Overview

Problem

Power modules face issues with inadvertent operation due to parasitic current and voltage signals, which existing approaches have not adequately addressed, leading to improper control and potential failures.

Innovation Solution

A power module apparatus with an integrated clamp circuit that reduces voltage charge-up at the gate of power devices to within 8 V peak to peak, effectively clamping parasitic signals and preventing parasitic turn-on, thereby enhancing control and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing approaches are used to address parasitic signals, then some level of control is maintained, but parasitic turn-on still occurs due to insufficient voltage clamping

Engineering Contradiction:

Improveprevention of parasitic turn-onVSAvoidparasitic voltage signals

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The clamp circuit is activated before parasitic turn-on can occur, applying a counteracting voltage to prevent the harmful effect. The circuit monitors gate voltage and applies clamping action in advance to counteract rising parasitic voltages before they reach turn-on thresholds.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The clamp circuit converts potentially harmful parasitic voltage rise into a beneficial controlled voltage clamping action. By intentionally providing a clamping path, the circuit transforms the harmful voltage spike into a controlled voltage reference, preventing damage while maintaining circuit operation.

Inventive Principle:

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

2Reliability

If voltage clamping is applied to reduce parasitic signals, then reliability improves, but additional circuit complexity is introduced

Engineering Contradiction:

Improvecontrol stabilityVSAvoidclamp circuit integration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The clamp circuit is merged with the existing gate driver circuitry, sharing common components such as the gate resistor and utilizing the same power supply rails. This integration approach adds clamping functionality without requiring completely separate circuitry, thereby limiting the increase in overall system complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The clamp circuit is designed to serve multiple functions: it provides voltage clamping to prevent parasitic turn-on, maintains proper gate voltage levels during normal operation, and works across different switching conditions. This multi-functionality reduces the need for additional specialized circuits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11652478B2Power modules having an integrated clamp circuit and process thereof

Publication Date: 2023.05.16 WOLFSPEED INC

AI summary

A power module apparatus includes a power substrate, at least one power device electrically connected to the power substrate and a gate-source board mounted relative to the power substrate, the gate-source board electrically connected to the at least one power device, a housing secured to the power substrate, and a clamping circuit electrically connected to the at least one power device. The clamping circuit being configured to reduce a voltage charge up at a gate of the at least one power device to within 8 V of a desired voltage.