Circuit Board Identification by RC Timing Without ADCs

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Solution Overview

Problem

Conventional identification circuits for circuit boards are costly due to the inclusion of analog-to-digital converters (ADCs) and face challenges in accurately identifying multiple boards without increasing precision, which restricts the addition of new circuit boards with different functions.

Innovation Solution

An identification circuit that uses a switching element, a circuit element group including a resistor and/or capacitor, and a controller to measure determination time based on connected identification resistors and capacitors, eliminating the need for ADCs and allowing for accurate identification using a time-based method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an ADC is used in the identification circuit, then identification capability is achieved, but cost increases significantly

Engineering Contradiction:
Improveidentification accuracyVSAvoidcost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the ADC from the identification circuit entirely, replacing it with a time-based measurement approach using a comparator. The identification function is achieved by measuring the time required for a capacitor to charge through identification resistors with different resistance values, eliminating the need for expensive ADC hardware while maintaining identification capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the electronic ADC-based measurement system with a time-domain measurement system using RC charging circuits. Instead of converting analog voltage to digital values, the system measures the time duration required for voltage to reach a threshold, replacing complex electronic conversion with simpler temporal measurement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If multiple circuit boards with different functions are added, then versatility improves, but identification accuracy decreases

Engineering Contradiction:
Improvenumber of circuit boardsVSAvoididentification accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent assigns different resistance values to identification resistors on different circuit boards, creating local quality differences that enable unique identification. Each circuit board has a specific resistance value characteristic that serves as its identification signature, allowing the system to distinguish between multiple boards with different functions while maintaining accurate identification.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If voltage-based identification is used, then identification is achieved, but errors occur due to voltage range limitations

Engineering Contradiction:
Improveidentification operationVSAvoididentification reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent transitions from voltage-based identification to time-based identification, adding a temporal dimension to the measurement process. Instead of comparing voltage levels that may overlap and cause errors, the system measures the time duration of RC charging processes, which provides distinct temporal signatures for different resistance values and eliminates voltage range-related errors.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This configuration reduces development and product costs, improves identification accuracy, and enables easy integration of new circuit boards by varying resistor and capacitor values, enhancing compatibility and reducing errors associated with voltage ranges.

Implementation Method 1

the identification capacitor is discharged by the identification resistor when the one circuit board is not selected by the switching element

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the controller is configured to measure a determination time, which is different for each circuit board, based on the connected identification resistor and/or the connected identification capacitor

Methodology Applied
Scientific EffectCapacitor charging/discharging: Capacitance

Data Source

PatentEP4231102A1Identification circuit and identification method
Publication Date: 2023.08.23 YOKOGAWA ELECTRIC CORP

AI summary

An identification circuit (10) for identifying one circuit board (30) among a plurality of circuit boards (30) includes a switching element (11) that switches the one circuit board (30) electrically connected to the identification circuit (10) among the plurality of circuit boards (30), a circuit element group (12) electrically connected to the switching element (11), and a controller (13) electrically connected to the switching element (11) and the circuit element group (12). Upon an identification resistor (Ri) and/or an identification capacitor (Ci) being electrically connected to the circuit element group (12) via the switching element (11), the controller (13) measures a determination time (T), which is different for each circuit board (10), based on the connected identification resistor (Ri) and/or the connected identification capacitor (Ci) and identifies the one circuit board (30) based on the measured determination time (T).