Semiconductor Resistance Measurement Using Reversed Voltage Phases

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Solution Overview

Problem

Existing semiconductor devices for measuring resistance values, such as thermistors, require significant time due to limitations in measurement resolution, counter frequency, and voltage division ratio, necessitating lengthy measurement periods and PI control adjustments.

Innovation Solution

A semiconductor device employing an analog-to-digital converter that generates output data by converting voltage levels between a reference resistor and a sensor resistor, using two conversion phases with reversed reference voltages to calculate resistance values accurately and quickly, thereby reducing measurement time and eliminating the need for PI control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional resistance measurement techniques are used with pull-up resistors and triangular wave signals, then measurement range can be achieved, but measurement time becomes excessively long (10ms or more)

Engineering Contradiction:

Improveresistance value measurement rangeVSAvoidmeasurement period

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent inverts the traditional measurement approach by switching the positions of high-potential and low-potential reference voltages between two conversion phases. Instead of using a fixed voltage division ratio with pull-up resistors, the invention applies reversed reference voltages to the sensor resistor and reference resistor in alternating phases, enabling rapid differential measurement that eliminates the need for slow triangular wave modulation and PI control adjustments.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs periodic switching between two conversion phases with reversed reference voltage configurations. By alternating between Phase 1 (high-potential to sensor resistor) and Phase 2 (low-potential to sensor resistor), the system performs repeated differential measurements that quickly converge to the resistance value without requiring the extended measurement periods of traditional methods.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If PI control is used to adjust common voltage for triangular wave generation, then measurement accuracy can be maintained, but adjustment time increases measurement period

Engineering Contradiction:

Improvecommon voltage accuracyVSAvoidvoltage adjustment time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts and eliminates the PI control mechanism from the measurement system. By using direct analog-to-digital conversion with reversed reference voltages, the invention removes the need for triangular wave generation and common voltage adjustment, thereby eliminating the time-consuming PI control loop while maintaining measurement accuracy through differential voltage comparison.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical feedback control system (PI controller adjusting common voltage) with a direct digital conversion approach. Instead of using analog triangular waves and feedback control, the invention uses sequential analog-to-digital conversion with reversed reference voltages, substituting a complex control mechanism with a simpler direct measurement method.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If measurement resolution and counter frequency are increased to improve accuracy, then measurement precision improves, but measurement time increases

Engineering Contradiction:

Improveresistance value accuracyVSAvoidmeasurement period

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary voltage establishment by applying reference voltages directly to the resistors before conversion. By pre-establishing the voltage conditions and using rapid analog-to-digital conversion, the system eliminates the need for extended measurement periods required by traditional counter-frequency-based methods, achieving high accuracy without time penalties.

Inventive Principle:

Principle #10Preliminary action

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 high-accuracy resistance value measurement in a short time, independent of measurement resolution, counter frequency, and voltage division ratio, with a reduced measurement period and no requirement for PI control adjustments.

Implementation Method 1

analog-to-digital converter that generates output data by converting voltage levels between a reference resistor and a sensor resistor

Methodology Applied

Scientific EffectVoltage division: Ohm's Law

Data Source

PatentUS11156645B2Semiconductor device

Publication Date: 2021.10.26 RENESAS ELECTRONICS CORP

AI summary

A semiconductor device includes an analog-digital conversion circuit that converts a voltage at a node between a reference resistor and a sensor resistor into output data, the reference resistor and the sensor resistor being connected in series. The semiconductor device calculates a resistance value of the sensor resistor using a first output data obtained in a first conversion phase and second output data obtained in a second conversion phase. In the first conversion phase, a high potential side voltage is applied to one end of the reference resistor and a low potential side voltage is applied to one end of the sensor resistor. In the second conversion phase, the low potential side voltage is applied to one end of the reference resistor and the high potential side voltage is applied to one end of the sensor resistor.