Parallel Shunt Resistor Current Detection Circuit
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Solution Overview
Problem
Existing power supply control apparatuses face challenges in detecting large currents when multiple loads are connected, leading to increased heat in shunt resistors and the need for multiple current detection circuits, which complicates the system and increases component count and processing requirements.
Innovation Solution
A current detection apparatus that uses a single current detection circuit to calculate the total current flowing through a power supply path by correlating the current through two shunt resistors connected in parallel, allowing for accurate detection and prevention of erroneous cutoffs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple shunt resistors are connected in parallel to detect large current, then the current detection capability is improved, but the number of current detection circuits must be increased proportionally
Solution Approach 1:
The patent uses only one current detection circuit to detect current through the first shunt resistor, then copies this detection result through arithmetic processing to calculate the total current. The arithmetic circuit multiplies the detected current by a predetermined coefficient (ratio of total current to first shunt current) to obtain the total current value, eliminating the need for multiple detection circuits.
Solution Approach 2:
The patent introduces an arithmetic circuit as an intermediary between the single current detection circuit and the control system. This arithmetic circuit performs the function of calculating total current by multiplying the detected current through the first shunt resistor by a predetermined coefficient, thereby mediating the relationship between partial current measurement and total current determination.
2Temperature
If multiple shunt resistors are connected in parallel to handle large current, then the heat resistance is improved, but the component count and circuit mounting area increase
Solution Approach 1:
The patent segments the current path by connecting multiple shunt resistors in parallel, dividing the total current into separate paths. This segmentation allows each shunt resistor to handle a portion of the current, improving heat dissipation and heat resistance without requiring each individual resistor to withstand the full current load.
Solution Approach 2:
The patent combines multiple shunt resistors in parallel configuration to share the current load and improve heat resistance, while simultaneously combining their electrical characteristics (current division ratio) into a single calculation formula. This allows the system to benefit from both the thermal advantages of multiple resistors and the simplicity of single-circuit detection.
3Power
If multiple shunt resistors are connected in parallel to detect large current, then the current handling capability is improved, but the arithmetic processing complexity increases
Solution Approach 1:
The patent transforms the complex multi-parameter measurement problem into a simple single-parameter measurement with a scaling factor. Instead of measuring current through multiple resistors and performing complex summation, the system measures current through one resistor and applies a predetermined coefficient (current ratio) to calculate the total current, significantly simplifying arithmetic processing.
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 detection of large currents without the need for multiple current detection circuits, reducing component count and processing complexity while preventing overcurrent cutoffs and improving heat management.
Implementation Method 1
A current detection circuit includes a shunt resistor connected in series with the semiconductor switching element, and can detect the current in the power supply path based on the voltage across the shunt resistor
Data Source
AI summary
Provided is current detection apparatus for detecting current flowing through a power supply path of a power supply control apparatus. The power supply path includes a first conductor and a second conductor. The current detection apparatus includes: a first and a second shunt resistor connected in parallel between the first and the second conductor, and a current detection circuit detecting: (1) current flowing through the first shunt resistor; and (2) current flowing from the first to the second conductor via both the first and second shunt resistors. The current detection apparatus further includes an arithmetic circuit that calculates current flowing through the power supply path based on a correlative relationship between the current flowing from the first to the second conductor via both the first and the second shunt resistor and current flowing through the first shunt resistor, and the current detected by the current detection circuit.