Current Sense Circuit for Bidirectional Sensing and Parasitic Calibration
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Solution Overview
Problem
Conventional high-side current sense circuits are limited in sensing both positive and negative currents, as they provide zero voltage when the current is negative, lacking a wide-range current sensing capability.
Innovation Solution
A current sense circuit design that includes a first and second sensing terminal, a sensing output terminal, and a current source, capable of sensing both positive and negative currents by adjusting the current source value and incorporating a calibration mode to compensate for inaccuracies due to parasitic resistance and environmental changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional high-side current sense circuit is used with a current sense resistor and operational amplifier, then the current sensing function is achieved with a linear relationship between output voltage and current, but the circuit cannot provide negative voltage when current is negative, limiting the sensing range
Solution Approach 1:
The patent inverts the conventional current sense circuit configuration by switching between two operational amplifier configurations: a standard inverting configuration for positive current sensing and a modified configuration with swapped input terminals for negative current sensing. This inversion approach enables the circuit to accurately sense both positive and negative currents by reversing the signal path when negative current is detected, thereby expanding the sensing range while maintaining measurement precision.
Solution Approach 2:
The patent implements dynamic switching between different operational amplifier configurations based on the current direction. A control mechanism monitors the current polarity and dynamically reconfigures the operational amplifier connections, transitioning from the standard configuration for positive current to the inverted configuration for negative current. This dynamic adaptability allows the circuit to maintain optimal sensing performance across the full current range.
2Reliability
If parasitic resistance and environmental variations are present in the current sense circuit, then the circuit becomes more robust in practical applications, but the current sensing accuracy deteriorates due to these parasitic effects
Solution Approach 1:
The patent incorporates feedback mechanisms that continuously monitor the output signal and adjust the sensing configuration to compensate for parasitic resistance and environmental variations. The feedback loop detects deviations caused by parasitic effects and dynamically adjusts the operational amplifier configuration or switching states to counteract these errors, thereby maintaining high sensing accuracy despite the presence of parasitic elements and environmental changes.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the operational amplifier configuration parameters (input terminal connections, feedback path arrangements) based on detected current conditions. This parameter switching allows the circuit to optimize its sensing characteristics for different operating conditions, compensating for parasitic resistance variations and environmental factors by changing the electrical parameters of the sensing path.
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 wide-range current sensing for both positive and negative currents, with improved accuracy by compensating for parasitic resistance and environmental variations through calibration, ensuring precise current detection.
Implementation Method 1
the voltage across the two terminals of the current sense resistor indicates the current flowing through the resistor and the device (I=V/R)
Data Source
AI summary
A current sense circuit for sensing a current flowing through a device is provide. The current sense circuit includes a first sensing terminal, a second sensing terminal, a sensing output terminal, and a current source. The first sensing terminal is configured to be coupled to a first terminal of a current sense resistor coupled in series with the device. The second sensing terminal is configured to be coupled to a second terminal of the current sense resistor. The sensing output terminal is configured to provide a sensing signal indicative of the current flowing through the current sense resistor. The current source is coupled to the second sensing terminal of the current sense circuit.