Leakage Compensation Circuit for Accurate Capacitive Measurement
Find Innovative SolutionsGenerate Solutions
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 the voltage behavior non-linear and reducing measurement accuracy.
Innovation Solution
A leakage compensation circuit using a replica device, voltage regulator, and current mirror to mirror the leakage current and regulate voltage, ensuring accurate and reliable measurements by compensating for the leakage 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 occur that falsify the measurement results
Solution Approach 1:
The patent creates a replica path with replica devices that are copies of the leaking devices in the measurement path. The replica leakage current mirrors the measurement path leakage current, allowing the harmful leakage effect to be copied and compensated. This is achieved by creating identical circuit paths with matching components that replicate the leakage behavior for compensation purposes.
Solution Approach 2:
The patent converts the harmful leakage current into a beneficial compensation signal. By mirroring the leakage current through the current mirror circuit and adding it to the measurement current, the previously harmful leakage effect becomes a useful compensation that cancels out the original leakage, transforming the problem into a solution.
2Reliability
If ESD protection devices are added to protect the measurement device, then device reliability is improved, but leakage current increases that impacts measurement accuracy
Solution Approach 1:
The patent creates replica ESD protection devices in the replica path that are identical to the ESD devices in the measurement path. These replica devices copy the leakage current characteristics of the protection devices, enabling the system to measure and compensate for the leakage introduced by the necessary protection components.
Solution Approach 2:
The patent introduces a replica path as an intermediary system that mediates between the ESD protection requirement and the measurement accuracy requirement. The replica path acts as a buffer that captures and mirrors the leakage current, allowing the main measurement path to maintain both protection and accuracy.
3Reliability
If voltage regulation is applied to maintain stable measurement conditions, then measurement reliability is improved, but circuit complexity increases
Solution Approach 1:
The patent merges the voltage regulation function with the leakage compensation function by using the same replica path and current mirror circuit for both purposes. The voltage regulator controls the replica path voltage to match the measurement path, while the current mirror simultaneously captures and transfers the leakage current, achieving multiple functions through integrated circuitry.
Solution Approach 2:
The replica path serves multiple functions simultaneously: it provides voltage regulation reference, generates the leakage current mirror signal, and enables compensation for leakage effects. This multi-functional design reduces overall circuit complexity compared to having separate dedicated circuits for each function.
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
The solution significantly improves the accuracy and reliability of capacitive or resistive measurements by effectively compensating for leakage-induced non-linearities, ensuring precise measurement results even when the device to be measured is connected via an ESD-protected test pad.
Implementation Method 1
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
Implementation Method 2
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
Data Source
AI summary
It is described a leakage compensation circuit for a measurement device which comprises a measurement circuit with a leaking device that is connected to a measurement path and causes a leakage current. The leakage compensation circuit comprises: i) a replica device of the leaking device, wherein the replica device is connected to a replica path, and wherein the replica device is configured to cause a replica leakage current that is essentially equal to the leakage current of the leaking device, ii) a voltage regulator which is connected 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, and iii) a current mirror which is connected 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 into the measurement path.