MOSFET Body Potential Control for Reverse Power Protection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Integrated circuits (ICs) can malfunction or be damaged due to reverse connections of external power sources, causing instantaneous large currents that burn out pins or wires, and existing ESD circuits may also be damaged in the process.

Innovation Solution

An electrostatic discharge (ESD) circuit incorporating at least one metal oxide semiconductor field effect transistor (MOSFET) and a control circuit, where the control circuit changes the potential of the MOSFET's body to turn it off when a reverse connection is detected, preventing damage from the reverse current flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an ESD circuit is designed to provide an ESD current path to protect the IC, then the IC is protected from ESD damage, but the IC may malfunction or be damaged when the external power source is reversely connected due to large current flowing through the ESD path

Engineering Contradiction:

ImproveIC protection from ESDVSAvoiddamage from reverse connection

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The ESD circuit dynamically changes its state based on power source connection status. The control circuit monitors the power source and adjusts the ESD circuit configuration: in normal operation, the ESD path is active for protection; when reverse connection is detected, the control circuit changes the body potential of the MOSFET to turn it off, isolating the ESD path and preventing damage from reverse current

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the body potential parameter of the MOSFET to control its conduction state. By adjusting the body potential through the control circuit, the MOSFET can be turned on for normal ESD protection or turned off when reverse connection is detected, thereby changing the electrical characteristics of the ESD path to prevent damage

Inventive Principle:

Principle #35Parameter changes

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

Effectively prevents IC malfunctions and damage by isolating the internal circuit from harmful currents generated by reverse connections of the external power source, thereby protecting the ESD circuit and IC pins.

Implementation Method 1

The control circuit is coupled to the at least one MOSFET for changing a potential of a body of the at least one MOSFET when the external power source is reversely connected, such that the at least one MOSFET is turned off

Methodology Applied

Scientific EffectMOSFET body potential control:

Data Source

PatentUS11257809B2Electrostatic discharge circuit and method for preventing malfunctioning of integrated circuit from reverse connection of power source

Publication Date: 2022.02.22 AIROHA TECHNOLOGY CORPORATION

AI summary

Disclosed are an electrostatic discharge circuit and a method for preventing malfunctions of an integrated circuit due to a reverse connection of a power source. The electrostatic discharge circuit includes at least one MOSFET for providing an electrostatic discharging current path, and a control circuit coupled to the at least one MOSFET. When an external power supply is reversely connected, the control circuit is configured to change a potential of a body of at least one MOSFET, such that the at least one MOSFET is turned off, thereby preventing the integrated circuit from malfunctioning caused by a current generated by the reverse connection of the external power source flowing through the at least one MOSFET.