Open-Drain Reset Output for PMIC Bond Wire Failure Signaling

Solution Overview

Problem

Existing PMICs in vehicles face challenges in signaling error conditions due to bonding wire failures, which prevent the reporting of failures to safety MCUs, and redundancy solutions are not always feasible.

Innovation Solution

The implementation of a field-effect transistor (FET) with a control circuit and internal pull-up resistors to manage the PMIC's reset output, ensuring the correct signaling of error conditions even in the absence of a bonding wire, using NMOS devices and negative voltage charge pumps to manage the FET's conductive and non-conductive states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an additional supply power source or second bonding wire is used to provide redundancy, then reliability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

ImprovereliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The PMIC uses its existing power management circuitry to monitor its own power supply status and generate reset signals when failures are detected, eliminating the need for separate redundant power sources or additional bonding wires. The system serves itself by using internal resources for safety monitoring.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The reset output circuit is designed to serve multiple functions: it provides normal reset functionality and simultaneously acts as a failure indication mechanism. The same circuit infrastructure is used for both operational control and safety monitoring, reducing the need for dedicated redundant components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If an additional supply power source or second bonding wire is used to provide redundancy, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:

ImprovereliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The PMIC uses its existing power management circuitry to monitor its own power supply status and generate reset signals when failures are detected, eliminating the need for separate redundant power sources or additional bonding wires. The system serves itself by using internal resources for safety monitoring.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The reset output circuit is designed to serve multiple functions: it provides normal reset functionality and simultaneously acts as a failure indication mechanism. The same circuit infrastructure is used for both operational control and safety monitoring, reducing the need for dedicated redundant components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Difficulty of detecting and measuring

If the PMIC pulls the reset output to low state to report failure, then error detection capability is improved, but the system fails when bonding wire connection is lost

Engineering Contradiction:

Improveerror detection capabilityVSAvoidfailure reporting reliability

Core Design Contradiction:

Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent introduces an intermediary mechanism where the reset output circuit acts as a mediator between the power supply status and the safety microcontroller. The circuit uses the existing reset output infrastructure to communicate power supply failures, translating internal failure states into external signals without requiring direct communication paths that could be vulnerable to bonding wire failures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback by continuously monitoring the power supply status through existing circuitry and automatically generating reset signals when failures are detected. This closed-loop monitoring ensures that failure information is reliably communicated to the safety microcontroller even when bonding wires are compromised.

Inventive Principle:

Principle #23Feedback

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

Ensures reliable signaling of error conditions to safety MCUs, meeting functional safety standards without the need for redundant power sources or additional bonding wires.

Implementation Method 1

selectively conducting, by a field-effect transistor (FET), a first current between an output terminal and a ground terminal of the IC to drive the output terminal to a low voltage state

Methodology Applied

Scientific EffectField-effect transistor conduction: Conduction (electrical)

Implementation Method 2

conducting a second current between a signal terminal of the IC and a gate of the FET to drive the FET to a conductive state

Methodology Applied

Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentUS12591281B2Reset output with open drain configuration for functional safety (FUSA) applications

Publication Date: 2026.03.31 SEMICON COMPONENTS IND LLC

AI summary

Reset output with open drain configuration for functional safety (FUSA) applications. Example embodiments include methods of operating an output of an integrated circuit (IC) including determining an error condition in the IC; generating a reset signal based on the determining the error condition in the IC; selectively conducting, by a field-effect transistor (FET), a first current between an output terminal and a ground terminal of the IC to drive the output terminal to a low voltage state, and thereby signaling the error condition in the IC; conducting a second current between a signal terminal of the IC and a gate of the FET to drive the FET to a conductive state; and selectively driving, in response to the reset signal, the FET to a non-conductive state.