Variable Sense Resistor Current Detection in Power Supplies
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Solution Overview
Problem
Current power supply devices require multiple types of current detecting devices to handle varying load currents, leading to increased complexity and reduced accuracy, especially when dealing with both low and high consumption currents.
Innovation Solution
A power supply device incorporating a semiconductor field-effect transistor (FET) with a built-in sense FET and a variable resistance sense resistor, allowing the resistance value to be adjusted based on the load current through a CPU-controlled switch configuration, enabling accurate current detection without the need for multiple A/D converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an A/D converter with wide dynamic range is used to detect both small and large consumption currents, then the device can handle various load types, but the current detecting accuracy decreases for small consumption currents
Solution Approach 1:
The patent applies dynamics by making the sense resistor value changeable based on the load current magnitude. The control unit switches between different sense resistor values (first sense resistor value for small currents, second sense resistor value for large currents) to optimize detection accuracy for different current ranges, resolving the contradiction between wide adaptability and measurement precision.
2Measurement precision
If an A/D converter with dynamic range matching specific load current is used to maintain detection accuracy, then current detecting accuracy improves, but the number of current detecting device types increases
Solution Approach 1:
The patent applies universality by designing a single current detecting device that can handle multiple current ranges. By incorporating a changeable sense resistor mechanism controlled by the control unit, one device type can accurately detect both small and large consumption currents, eliminating the need for multiple specialized device types while maintaining detection accuracy.
3Measurement precision
If multiple types of current detecting devices are used to handle different consumption currents, then detection accuracy for each load type is maintained, but the device complexity and part types increase
Solution Approach 1:
The patent applies merging by combining multiple detection capabilities into a single current detecting device. The control unit integrates the functionality of multiple specialized detectors by dynamically switching sense resistor values, allowing one unified device to replace multiple device types while maintaining accurate detection across all current ranges.
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 allows for accurate detection of consumption currents across different loads with reduced types of parts, minimizing the need for multiple A/D converters and simplifying the power supply circuitry, while also preventing overheating by controlling the power supply.
Implementation Method 1
a sense signal corresponding to the consumption current is obtained from a semiconductor field-effect transistor
Implementation Method 2
a voltage drop generated in the sense resistor is subjected to A/D conversion to detect a voltage
Data Source
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AI summary
A current detecting device includes a sense resistor through which a sense current corresponding to a consumption current supplied to a load flows, and an A/D converter configured to perform A/D conversion on a voltage drop generated by the sense current flowing through the sense resistor to detect the consumption current. A resistance value of the sense resistor is variably provided.