High-Side Current Monitor With Band-Split Gain for Isolation Noise
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Solution Overview
Problem
Existing current monitoring systems for electrostatic chucks face challenges in accurately measuring high-side currents due to noise limitations in isolation amplifiers, which affects capacitance sensing resolution, especially as processing techniques require higher power amplifiers and output currents.
Innovation Solution
A high-side current monitor that splits the current signal into different frequency bands, applies distinct gain levels using high-pass and low-pass filters, and communicates the adjusted signal through a galvanically isolated path to produce multiple output signals for precise current monitoring, effectively reducing noise interference and enhancing resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high side current sensing is used to avoid noise, then measurement precision is improved, but device complexity increases due to isolation requirements
Solution Approach 1:
The patent segments the current signal into different frequency bands (AC and DC components) and processes each band separately with appropriate gain levels before combining them. This segmentation allows the system to handle the high-voltage signal and low-voltage measurement sides independently through the isolation amplifier, reducing the complexity burden on any single component while maintaining measurement precision.
2Adaptability or versatility
If gain is reduced to accommodate higher power amplifiers, then adaptability to higher power is improved, but measurement precision deteriorates due to capacitance signal falling below noise floor
Solution Approach 1:
The patent applies different gain levels to different frequency bands of the current signal. Specifically, the AC component (used for capacitance sensing) is amplified with a higher gain while the DC component (used for current measurement) uses a lower gain. This local differentiation of gain quality allows the system to maintain high measurement precision for capacitance sensing while accommodating higher power amplifiers, resolving the contradiction between adaptability and precision.
3Reliability
If isolation amplifier is used to separate high voltage from measurement, then safety and reliability are improved, but measurement precision deteriorates due to electrical noise
Solution Approach 1:
The patent performs preliminary signal processing by splitting the current signal into frequency bands and applying appropriate gain levels before the signal enters the isolation amplifier. By pre-amplifying the AC component and pre-processing the signal characteristics, the system ensures that the signal entering the isolation amplifier is already optimized, thereby minimizing the impact of noise introduced by the isolation amplifier and maintaining measurement precision while ensuring safety.
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 allows for improved resolution in current and capacitance measurements by amplifying AC current information separately before isolation, reducing noise impact and maintaining signal accuracy within the isolation amplifier's specifications, thus addressing the limitations of prior art systems.
Implementation Method 1
using a high-pass filter and a low-pass filter
Implementation Method 2
An isolation amplifier is configured to communicate the adjusted signal from the high-voltage side to the low-voltage side while electrically isolating the high-voltage side from the low-voltage side
Data Source
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AI summary
Systems, methods, and an apparatus for current monitoring are disclosed. A current monitor comprises a high-voltage side configured to obtain a signal indicative of current through a conductor and apply different levels of gain to different frequency bands of the signal to produce an adjusted signal. A low-voltage side of the current monitor is electrically isolated from the high-voltage side and is configured to split the adjusted signal to produce a plurality of output signals that are each indicative of a level of current at one of the different frequency bands. An isolation amplifier is configured to communicate the adjusted signal from the high-voltage side to the low-voltage side while electrically isolating the high-voltage side from the low-voltage side.