Slew Rate Detection Circuit for Fast Sensor Response

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Solution Overview

Problem

Sensing systems face delays in responding to changes in physical properties due to mechanical and electrical component response times, noise reduction measures, and multiple task processing, which can prolong the time to provide accurate measurement values.

Innovation Solution

A sensing system with a slew rate detection circuit that generates an interrupt signal when the analog electrical signal's slew rate exceeds a threshold, allowing the control circuit to prioritize converting the primary analog sensor signal, thereby reducing conversion cycle time and optimizing step response time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the sensing system performs multiple sensing system operations in sequence, then comprehensive processing is achieved, but the response time to process steps is prolonged

Engineering Contradiction:
Improveresponse timeVSAvoidmultiple task processing
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The control circuit dynamically adjusts its operational mode based on the interrupt signal state. When a slew rate exceedance is detected, the system switches to a simplified mode that performs only the measurement determination operation, bypassing other scheduled operations. This dynamic adaptation allows the system to optimize response time for critical events while maintaining comprehensive processing for normal operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an interrupt signal as an intermediary mechanism that mediates between the slew rate detection circuit and the control circuit. This interrupt signal acts as a trigger that interrupts the normal sequence of operations, allowing the control circuit to prioritize and execute the measurement determination operation immediately, thereby reducing overall response time without permanently altering the system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the A/D converter converts multiple analog signals in sequence, then all signals are processed, but the conversion cycle time increases

Engineering Contradiction:
Improveconversion cycle timeVSAvoidsignal processing priority
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The A/D converter's operation is made dynamic through interrupt-driven conversion. Instead of following a fixed sequential schedule, the converter can be triggered to convert the primary analog sensor signal immediately when a slew rate exceedance is detected. This allows the system to adapt the conversion cycle time based on the urgency of the measurement need while maintaining the capability to process multiple signals.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary detection of slew rate exceedances through the dedicated slew rate detection circuit, which operates continuously or at regular intervals. This preliminary action allows the system to identify critical events before they require full measurement processing, enabling the A/D converter to prioritize conversions accordingly and reduce overall conversion cycle time for critical measurements.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If the control circuit performs comprehensive sensing system operations, then all processing tasks are completed, but the time to determine measurement values during slewing increases

Engineering Contradiction:
Improvemeasurement value accuracyVSAvoiddetermination delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts the measurement determination function from the sequence of comprehensive sensing system operations by using an interrupt mechanism. When a slew rate exceedance is detected, the interrupt signal causes the control circuit to extract and execute only the measurement determination operation, bypassing other non-critical processing tasks. This extraction reduces determination delay while maintaining measurement precision for critical events.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The slew rate detection circuit provides continuous feedback to the control circuit about the rate of change of the analog signal. This feedback mechanism allows the control circuit to monitor the slewing condition and trigger appropriate responses. When the feedback indicates a critical slew rate exceedance, the system prioritizes measurement determination, thereby reducing delay without compromising the accuracy of the measurement value.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2894534B1Slew rate detection circuit
Publication Date: 2019.03.06 SCHNEIDER ELECTRIC SYSTEMS USA INC
  • EP2894534B1 patent drawingFigure 1
  • EP2894534B1 patent drawingFigure 2
  • EP2894534B1 patent drawingFigure 3

AI summary

A sensing system comprising a sensor for generating an analog electrical signal indicative of a sensed physical property and an A/D converter for converting the analog electrical signal into a digital electrical signal. A control circuit connected to the A/D converter is configured to receive the digital electrical signal and to perform a plurality of sensing system operations including determining a measurement value of the physical property as a function of said received digital electrical signal. A slew rate detection circuit connected to the sensor is configured to detect when the analog electrical signal indicates a slew rate that exceeds a threshold value, and to generate an interrupt electrical signal when the slew rate is detected as exceeding the threshold value. The control circuit determines a measurement value of the physical property in response to receiving the interrupt signal.