Current-Sensing Switch Shutdown for Accurate Overcurrent Detection
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Solution Overview
Problem
The variation in manufacturing of sensing resistors incorporated in control ICs leads to deteriorated overcurrent detection accuracy in semiconductor devices due to increased variation in overcurrent detection values.
Innovation Solution
A semiconductor device configuration that includes a switching device with a current sensing portion, a control IC with a gate drive unit, a sensing resistor connected between the emitter of the main and current sensing portions, and a comparator that compares the sense voltage with a reference voltage, ensuring the sense voltage is at least 1 V for shutdown, thereby minimizing the impact of manufacturing variations on overcurrent detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a sensing resistor is incorporated in the control IC for miniaturization, then device size is reduced, but manufacturing variation increases leading to deteriorated overcurrent detection accuracy
Solution Approach 1:
The patent changes the voltage parameter by ensuring the sense voltage is at least 1V when shutdown occurs. This parameter change makes the overcurrent detection less sensitive to manufacturing variations in the sensing resistor, as the absolute voltage threshold provides a more stable reference point compared to current-based detection.
2Ease of manufacture
If the sensing resistor manufacturing variation increases, then production flexibility improves, but overcurrent detection accuracy deteriorates
Solution Approach 1:
The patent converts the harmful effect of sensing resistor manufacturing variation into a benefit by using a 1V sense voltage threshold. This threshold transforms the detection mechanism to be less sensitive to resistor value variations, allowing broader manufacturing tolerances while maintaining detection accuracy.
3Measurement precision
If the sense voltage is lowered to improve sensitivity, then detection sensitivity increases, but manufacturing variation impact increases
Solution Approach 1:
The patent sets the sense voltage parameter to at least 1V, which optimizes the balance between sensitivity and reliability. This voltage level provides sufficient signal strength for reliable detection while being high enough to minimize the relative impact of manufacturing variations in the sensing resistor.
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 enhances the overcurrent detection accuracy by stabilizing the sense voltage and improving the energization capability of the current sensing portion, ensuring safe operation and reduced risk of switching device failure.
Implementation Method 1
a sensing resistor connected between an emitter of the main portion and an emitter of the current sensing portion and formed inside the control IC
Implementation Method 2
a comparator comparing a sense voltage applied to the sensing resistor with a reference voltage
Data Source
AI summary
A semiconductor device includes: a switching device including a main portion and a current sensing portion for detecting a current value of the main portion; a control IC including a gate drive unit that drives the switching device; a sensing resistor connected between an emitter of the main portion and an emitter of the current sensing portion and formed inside the control IC; a comparator comparing a sense voltage applied to the sensing resistor with a reference voltage; and a shut-down circuit shutting down an energization of the switching device when the sense voltage exceeds the reference voltage, wherein the sense voltage is more than or equal to 1 V when the energization of the switching device is shut down.