Current-Sensing Resistor Segmentation for Wide-Range Accuracy
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Solution Overview
Problem
Existing current sensing circuits in electronic devices face challenges in achieving accurate current measurement across a wide range of power applications, from low-power to high-power, while minimizing costs and integrated circuit die area.
Innovation Solution
The proposed system includes a main integrated circuit (IC) with current measurement circuitry, an auxiliary current sense resistor, and an auxiliary pair of Kelvin sense resistors. The main IC injects a known sink current, which is split between a main current path and an auxiliary current path, allowing for accurate current measurement and adjustment for inaccuracies in sense resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single sense resistor is used for current sensing, then the circuit complexity is reduced, but the measurement precision deteriorates because it cannot accurately handle both low-power and high-power applications simultaneously
Solution Approach 1:
The current sensing function is segmented into two separate sense resistors: a first sense resistor for low-power applications and a second sense resistor for high-power applications. Each resistor is optimized for its specific power range, allowing accurate measurement across the full power spectrum without requiring a single complex resistor design.
Solution Approach 2:
The current sensing circuit is designed with multi-functionality by incorporating both low-power and high-power sense resistors along with switching circuitry. The system can universally handle both low-power and high-power current sensing tasks by selectively activating the appropriate resistor and measurement path based on the application requirements.
2Measurement precision
If a high-precision sense resistor is used for accurate current measurement, then the measurement precision improves, but the integrated circuit die area increases
Solution Approach 1:
The sensing function is divided between two specialized resistors rather than using one large high-precision resistor. The first sense resistor handles low-power measurements and the second sense resistor handles high-power measurements, allowing each resistor to be smaller and more efficiently sized for its specific function, thereby reducing total die area.
Solution Approach 2:
Instead of using a single large high-precision resistor for all power levels, the design creates two separate sense resistors that are each optimized for specific power ranges. This copying approach allows the system to achieve high measurement precision across different power levels without requiring one oversized resistor that would consume excessive die area.
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 solution enables accurate current sensing across various power applications, optimizing signal-to-noise ratio and minimizing errors, while maintaining cost-effectiveness and efficient use of integrated circuit resources.
Implementation Method 1
measurement circuitry may determine a current flowing through the sense resistor by measuring the voltage across the resistor and calculating the current required to induce such voltage across the resistor in accordance with Ohm's Law
Data Source
AI summary
In accordance with embodiments of the present disclosure, a system may include a main integrated circuit (IC) comprising current measurement circuitry, an auxiliary current sense resistor coupled to the main IC, and an auxiliary pair of Kelvin sense resistors coupled between the auxiliary current sense resistor and the current measurement circuitry. The main IC may further comprise current injection circuitry configured to inject a known sink current which is split between a main current in a first path and an auxiliary current in a second path comprising the auxiliary current sense resistor.