Safe State Controller for Asynchronous Driver Protection

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Solution Overview

Problem

Existing driver control systems in electronic systems, such as those using MOSFETs, may fail to reliably transition to a safe state in response to trigger conditions like short circuits or excessive current, due to software execution errors or interruptions, potentially leading to device damage.

Innovation Solution

A microcontroller unit with a processor core and safe state controller, which can asynchronously transition drivers to a predefined safe state through hardware-based logic, independent of software control, using programmable registers and safe state logic to detect trigger conditions and generate kill signals for drivers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If software control is used to manage driver state transitions, then system complexity is reduced and ease of operation is improved, but reliability deteriorates due to potential software execution errors or interruptions

Engineering Contradiction:

Improvedriver controlVSAvoidsafe state transition

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

An intermediary hardware module (safe state controller) is introduced between the processor and driver circuits. This controller receives instructions from the processor but independently manages the driver state transitions through dedicated hardware logic, isolating the critical safe state function from software execution paths and eliminating reliance on software timing and control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The software-based driver control mechanism is replaced with a hardware-based implementation. The safe state controller uses hardware logic circuits to monitor trigger conditions and execute state transitions, substituting the mechanical/software execution model with an electrical/hardware model that operates independently of software instructions and provides deterministic behavior.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If hardware-based safe state controller is implemented, then reliability of safe state transition is improved, but device complexity increases

Engineering Contradiction:

Improvesafe state transitionVSAvoidcontroller architecture

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The controller architecture is segmented into functionally independent modules: a processor core for high-level control, a dedicated safe state controller for critical functions, and individual driver circuits for device control. Each module has a specific responsibility, and the safe state controller is further divided into trigger condition detection logic and state transition logic, making the overall complex system manageable and verifiable.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The safe state controller is designed as a universal module that can manage multiple driver circuits through a standardized interface. The trigger condition detection and state transition mechanisms are implemented generically to handle various driver types and failure modes, reducing the need for separate dedicated hardware for each driver and thereby limiting the increase in overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8825921B2Technique and system to control a driver state

Publication Date: 2014.09.02 SILICON LABORATORIES INC

AI summary

A technique includes executing at least one instruction on a processor to control a driver circuit; and in response to a predetermined trigger condition, asynchronously causing the driver circuit to enter a predetermined state.