Leakage Compensation Circuit for Precise Capacitive Measurement
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Solution Overview
Problem
Capacitive or resistive measurement devices are susceptible to leakage currents, which introduce non-linearities and falsify measurement results due to external components like electrostatic discharge protection, making it challenging to achieve accurate and reliable measurements.
Innovation Solution
A leakage compensation circuit using a replica device, voltage regulator, and current mirror to mirror and regulate the leakage current, ensuring the replica device experiences the same conditions as the measurement device, thereby compensating for the leakage-induced current loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a measurement current is used to generate a voltage for measurement, then the measurement function is achieved, but leakage currents falsify the measurement results
Solution Approach 1:
The patent creates a replica of the leaking device (ESD protection structure) that generates an identical leakage current. This replica leakage current is then mirrored into the measurement path to compensate for the actual leakage, allowing the measurement system to account for and eliminate the harmful leakage effects while maintaining accurate measurements
2Reliability
If electrostatic discharge protection is added to protect the measurement device, then device reliability is improved, but leakage current increases and falsifies measurements
Solution Approach 1:
The patent introduces a replica device as an intermediary element that experiences the same leakage conditions as the actual ESD protection but does not interfere with the measurement. The leakage current from this intermediary replica is mirrored and used to compensate for the harmful leakage in the measurement path, thus preserving both the protective function and measurement accuracy
3Measurement precision
If a leakage compensation circuit is added, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The compensation circuit uses a simplified replica of the leaking device rather than complex compensation mechanisms. By copying the essential leakage-generating structure and using a current mirror to transfer the replica leakage current to the measurement path, the circuit achieves accurate leakage compensation with minimal additional complexity
Solution Approach 2:
The patent replaces complex active compensation circuits with a passive replica device and current mirror structure. The current mirror automatically mirrors the replica leakage current without requiring complex control logic or active regulation, simplifying the overall compensation mechanism while maintaining effectiveness
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 approach significantly enhances the accuracy and reliability of measurement results by efficiently compensating for leakage currents, ensuring the measurement device operates with improved linearity and precision.
Implementation Method 1
a current mirror which is connected/connectable to the measurement path and to the replica path, wherein the current mirror is configured to mirror the replica leakage current of the replica device (in the replica path) into the measurement path
Implementation Method 2
a voltage regulator which is connected/connectable to the measurement path and to the replica path, wherein the voltage regulator is configured to regulate the voltage in the replica path based on the voltage of the measurement path
Data Source
Figure 1
AI summary
It is described a leakage compensation circuit (120) for a measurement device (100) which comprises a measurement circuit (110) with a leaking device (111) that is connected to a measurement path (115) and causes a leakage current (112). The leakage compensation circuit (120) comprises: i) a replica device (121) of the leaking device (111), wherein the replica device (121) is connected to a replica path (125), and wherein the replica device (121) is configured to cause a replica leakage current (122a) that is essentially equal to the leakage current (112) of the leaking device (111), ii) a voltage regulator (130) which is connected to the measurement path (115) and to the replica path (125), wherein the voltage regulator (130) is configured to regulate the voltage in the replica path (125) based on the voltage of the measurement path (115), and iii) a current mirror (140) which is connected to the measurement path (115) and to the replica path (125), wherein the current mirror (140) is configured to mirror the replica leakage current (122a) of the replica device (121) into the measurement path (115).