On-Chip Current Sensing With PVT-Matched Compensation Paths
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Solution Overview
Problem
Integrated circuit (IC) chips face challenges in current detection due to variations in circuit components caused by process, voltage supply, and temperature changes, which affect power delivery efficiency in applications like USB interfaces.
Innovation Solution
A system within the IC chip includes a power switch circuit and a current detection circuit that compensates for these variations by using a sense circuit path with matched resistance values to compare voltage drops across different paths, providing accurate current detection without external resistive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional current detection methods are used in IC chips, then current detection can be implemented, but measurement precision deteriorates due to component variations from process, voltage, and temperature changes
Solution Approach 1:
The patent creates a copy of the power circuit path as a sense circuit path with matched components (transistors, conductive traces, resistors). By copying the exact circuit topology and component characteristics, the sense path experiences identical PVT variations, allowing these variations to cancel out when comparing voltage drops, thereby achieving high current detection accuracy despite component variations
Solution Approach 2:
The patent implements a feedback mechanism where the voltage drop across the sense circuit path is compared with the voltage drop across the power circuit path using a differential amplifier. This comparison provides feedback that compensates for PVT variations, enabling accurate current detection by continuously adjusting for environmental and manufacturing variations
2Measurement precision
If external resistive elements are used for current detection, then current measurement can be performed, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the current detection function from external components and integrates it entirely within the IC chip. By taking out the need for external resistive elements and implementing the detection functionality using only on-chip components (transistors, conductive traces, and integrated resistors), the patent simplifies the overall device while maintaining detection capability
Solution Approach 2:
The patent merges the power delivery function and current detection function into a single integrated circuit. The sense circuit path is integrated alongside the power circuit path on the same chip, combining multiple functions (power switching, current sensing, variation compensation) into one unified device, thereby reducing external component requirements
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 detection and limiting, improving power delivery efficiency while reducing manufacturing costs and component tolerances, effectively canceling out process, voltage, and temperature variations.
Implementation Method 1
A comparator circuit can be configured to compare a voltage drop across the power circuit path to a voltage drop across the sense circuit path
Data Source
AI summary
A system can provide current detection in an integrated circuit (IC) chip while compensating for variations in circuit components resulting from process, voltage supply, temperature, or combinations thereof. The system can include the IC chip that has a power switch circuit that includes a power circuit path including a first transistor connected to a power source through a first conductive trace that has a first resistance value, and to a load by a second conductive trace having a second resistance value. A current detection circuit is configured to compensate for the variations in the power switch circuit using a sense circuit path that is configured to match process, voltage supply, and temperature variations in the power circuit path.