Monolithic Half-Bridge Circuit With Switch-Node Substrate Coupling

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Solution Overview

Problem

In some circuit configurations, undesired voltages appear across circuit elements, potentially damaging the circuitry and causing operational issues, and maintaining a substrate at a certain voltage can have unintended consequences.

Innovation Solution

A half-bridge circuit design is implemented, where a switch node is connected to the substrate, and capacitance between the switch node and the substrate is increased to control and reduce voltages, using a monolithic die with a high-side and low-side switch, and a conductive structure with a capacitor or diode to manage voltage potentials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the substrate is maintained at a fixed voltage potential, then the circuit operation is stabilized, but undesired voltages appear across circuit elements causing damage and operational issues

Engineering Contradiction:

Improvesubstrate voltage stabilityVSAvoidundesired voltages across circuit elements

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the traditional approach by disconnecting the substrate from ground potential and instead connecting the switch node to the substrate. This inversion allows the substrate to follow the switch node voltage, eliminating harmful voltage differentials across circuit elements while maintaining stable operation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the voltage potential parameter of the substrate from a fixed ground reference to a dynamic potential that follows the switch node. This parameter change transforms the substrate from a source of voltage stress to a protective reference, eliminating undesired voltages across circuit elements.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If a conventional half-bridge circuit is used with separate ground connections, then circuit functionality is achieved, but voltage divider issues and dynamic RDSon effects occur

Engineering Contradiction:

Improvecircuit functionalityVSAvoidvoltage divider issues and dynamic RDSon effects

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent merges the substrate connection with the switch node by directly coupling them, eliminating the need for separate ground connections. This merging removes the voltage divider effect and reduces dynamic RDSon effects by ensuring the substrate potential follows the switch node potential throughout operation.

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 design effectively limits electric fields across the device, reducing dynamic RDSon effects and preventing voltage divider issues, thereby protecting the circuitry and ensuring stable operation.

Implementation Method 1

capacitance between the switch node and the substrate is increased to control and reduce voltages

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11876437B2Monolithic integrated half-bridge circuit

Publication Date: 2024.01.16 INFINEON TECH AUSTRIA AG

AI summary

According to some embodiments, a half-bridge circuit is provided. The half-bridge circuit includes a substrate, a monolithic die over the substrate, a switch node, a high-side switch integrated with the monolithic die and coupled to the switch node, and a conductive structure including a first terminal coupled to the substrate and a second terminal coupled to the switch node.