Current Detection Apparatus Temperature Compensation via Segmentation
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Solution Overview
Problem
Current detection apparatuses experience delays in responding to fluctuations in load current due to the conversion of measured voltages to digital values, which affects the accuracy of current detection in semiconductor switches.
Innovation Solution
A current detection apparatus that includes a voltage detector, a candidate voltage generator with plural correction resistors, and a correction voltage selector, which generates and selects candidate voltages based on corrected magnification scales to directly correct the current value without digital conversion, addressing the temperature characteristics of semiconductor switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measured voltage is converted to digital values for processing, then current detection accuracy is improved, but response delay occurs due to conversion time
Solution Approach 1:
The patent segments the correction process by pre-calculating correction values for different temperature ranges and storing them in a correction table. Instead of performing continuous digital conversion and calculation, the system divides the temperature range into discrete segments and selects the appropriate correction value based on the detected temperature range, thereby reducing processing time while maintaining accuracy.
Solution Approach 2:
The patent performs preliminary action by pre-calculating correction values for various temperature conditions and storing them in advance in a correction table. When temperature compensation is needed, the system simply retrieves the pre-computed correction value corresponding to the current temperature range, eliminating the need for real-time calculation and reducing response delay.
2Measurement precision
If temperature compensation is performed through digital calculation, then current detection accuracy under varying temperature is improved, but processing complexity increases
Solution Approach 1:
The patent segments the temperature range into multiple discrete intervals and pre-calculates correction values for each segment. The correction table stores correction values corresponding to different temperature ranges, allowing the system to select the appropriate correction by simple comparison rather than complex real-time calculation, thus reducing processing complexity while maintaining temperature compensation accuracy.
Solution Approach 2:
The patent changes the parameter representation by storing correction values in a lookup table indexed by temperature range. Instead of performing complex mathematical calculations with temperature parameters in real-time, the system transforms the problem into a simple table lookup operation based on the detected temperature range, significantly reducing processing complexity.
3Speed
If correction values are pre-stored in a correction table, then response speed is improved, but memory requirements increase
Solution Approach 1:
The patent segments the temperature range into multiple discrete intervals, with each segment having its correction value stored in the correction table. By dividing the continuous temperature range into discrete segments, the system stores only the necessary correction values for each segment rather than continuous data, optimizing the balance between response speed and memory usage.
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 suppresses delays in current detection, allowing for real-time correction of load current fluctuations and improved accuracy in determining the lock state and short circuit conditions of motors.
Implementation Method 1
a voltage detector 110 that detects a measured voltage generated across terminals of the semiconductor switch according to the load current and an on-resistance of the semiconductor switch
Implementation Method 2
a temperature detector 120 that detects a temperature of the semiconductor switch as a measured temperature
Implementation Method 3
The candidate voltage generator includes plural correction resistors connected in series and connecting the output terminal and a ground. The candidate voltage generator generates plural candidate voltages at respective sections across the corresponding correction resistors. The plural candidate voltages are respectively calculated by multiplying a plurality of correspondingly corrected magnification scales to the detected voltage.
Data Source
AI summary
A current detection apparatus includes a voltage detector, a candidate voltage generator, a temperature detector and a correction voltage selector. The voltage detector includes an output terminal for outputting a detected voltage according to a load current. The candidate voltage generator includes correction resistors connected in series and connecting the output terminal and a ground. The candidate voltage generator generates candidate voltages at respective sections across the corresponding correction resistors. The temperature detector detects a temperature of a semiconductor switch. The correction voltage selector selects one of the candidate voltages as a corrected voltage. The one of the candidate voltages is weighted with corresponding one of the corrected magnification scales corresponding to an on-resistance of the semiconductor switch at the measured temperature. The corrected voltage indicates a corrected current value with correction of the load current according to the measured temperature.