Current-Controlled Semiconductor Device Gain Offset Correction

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Solution Overview

Problem

Current detection circuits integrated into IC chips experience significant fluctuations in gain and offset values due to temperature changes and reference voltage variations, leading to increased current detection errors in electromotive actuators.

Innovation Solution

A current-controlled semiconductor device with correction value calculating means that adjusts gain and offset values using temperature measurements and measured current values from constant current sources, allowing for accurate current detection within a single-chip IC by employing a microcontroller and memory elements to calculate and apply corrections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the current detection circuit is incorporated into the IC chip, then the size and cost of the control unit are reduced, but the gain a and offset b fluctuate greatly causing increased current detection error

Engineering Contradiction:
Improvesize of control unitVSAvoidcurrent detection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by measuring the currents of constant current sources at different temperatures in advance, storing these measurement values in memory elements, and using them to calculate correction values for gain and offset before actual current detection. This allows the system to compensate for temperature-induced fluctuations without requiring external calibration during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using measured current values from constant current sources to calculate correction values that are then applied to correct the detected current values. The system continuously monitors temperature changes and adjusts gain and offset parameters based on stored reference measurements, creating a closed-loop compensation mechanism that maintains detection accuracy despite internal fluctuations.

Inventive Principle:
Principle #23Feedback

2Device complexity

If the current detection circuit is incorporated into the IC chip, then the number of external parts is reduced, but temperature fluctuations cause significant changes in gain a and offset b

Engineering Contradiction:
Improvenumber of external partsVSAvoidstability of gain and offset
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent applies self-service by enabling the current detection circuit to automatically compensate for its own temperature-induced errors using internal constant current sources and memory elements. The system measures reference currents at different temperatures, stores these characteristics, and uses them to self-correct detection errors without requiring external calibration equipment or additional stable reference components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements parameter changes by dynamically adjusting the gain and offset parameters of the current detection circuit based on temperature conditions. The system stores measurement values obtained at different temperatures and selects or interpolates appropriate correction parameters according to the current temperature, allowing the circuit to adapt its characteristics to compensate for thermal drift.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If correction values are calculated using temperature measurements, then current detection accuracy is improved, but the device requires additional memory elements and processing

Engineering Contradiction:
Improvecurrent detection accuracyVSAvoidcomplexity of correction circuit
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent reduces processing complexity during operation by performing the complex measurement and calculation work in advance. The system measures currents at different temperatures during manufacturing or initial setup, calculates correction values, and stores them in memory elements. During actual use, the system only needs to read stored values and apply simple corrections, significantly reducing real-time processing requirements.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2320547B1Current-controlled semiconductor device and control unit using the same
Publication Date: 2016.10.12 HITACHI AUTOMOTIVE SYST LTD
  • EP2320547B1 patent drawingFigure 1
  • EP2320547B1 patent drawingFigure 2~3
  • EP2320547B1 patent drawingFigure 4

AI summary

The present invention aims to provide a current-controlled semiconductor device (100) which corrects fluctuations of both gain and offset of a current detection circuit (120) to thereby enable high-accuracy current detection within a single-chip IC, and a control unit using the same. The current-controlled semiconductor device (100) is provided on the same semiconductor chip with a MOSFET (110H), two constant current sources (133,135), and a current detection circuit (120) which detects a current of the MOSFET and currents of the constant current sources. Further, the constant current sources are equipped with an external connecting terminal (T5) for measuring their current values. A correction measured-value holding register (145) holds therein the current values of the constant current sources, which have been measured from outside.