ADC Input Pin Mode Switching for Automotive Safety ICs
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Solution Overview
Problem
In automotive safety critical systems, single-chip solutions face challenges in implementing additional signaling and power supply paths for failure modes due to pin limitations, which restrict the number of features that can be integrated on a single chip.
Innovation Solution
Incorporating a comparator circuit with a threshold outside the normal input range of an analog-to-digital converter (ADC) on a single integrated circuit, allowing for mode switching between normal and safety modes by monitoring the input signal and activating additional functional circuits via the ADC input pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional signaling and power supply paths are implemented for failure modes, then safety functionality is improved, but the number of package pins required increases
Solution Approach 1:
The ADC input pin is designed to perform multiple functions: it serves as both a normal analog input for signal conversion and a mode selection input for activating safety modes. By applying a voltage outside the ADC's normal input range, the pin can indicate failure modes without requiring a separate dedicated pin, thus achieving multi-functionality and reducing the total pin count while maintaining safety functionality
Solution Approach 2:
The invention utilizes changes in the voltage parameter at the ADC input pin to encode different operational modes. By varying the voltage level beyond the normal input range (e.g., exceeding the maximum input voltage or going below the minimum), the system can distinguish between normal operation and various failure modes, allowing mode selection through parameter variation rather than requiring additional signaling paths
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
Enables the activation of safety modes in gate driver integrated circuits without additional pins, enhancing functionality and reliability in safety-critical automotive systems by utilizing the ADC input pin to communicate digital signals for mode control.
Implementation Method 1
monitoring the signal at the input pin using a first comparator having a first threshold outside of the first input range
Data Source
AI summary
In accordance with an embodiment, a method includes performing an analog-to-digital conversion on a signal at an input pin of an integrated circuit using an analog-to-digital converter having a first input range, monitoring the signal at the input pin using a first comparator having a first threshold outside of the first input range, operating the integrated circuit in a first mode when the signal at the input pin is within the first input range, and operating the integrated circuit in a second mode different from the first mode when the signal at the input pin is outside of the first input range and crosses the first threshold.