ESD Detector Capacitive Coupling and Discharge Path
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Solution Overview
Problem
Existing ESD event detectors face issues with false detections due to interference from signals with similar spectra, inability to recognize multiple successive events, and high power consumption, which affects accuracy and usability, especially in battery-powered systems.
Innovation Solution
A device and method utilizing capacitive couplings with a commutation device to rapidly discharge electrostatic charge, incorporating a processor for switching between discharge paths, low-pass filtering, and peak detection to isolate ESD events from noise, allowing for low power consumption and accurate detection of multiple events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high frequency electromagnetic radiation detection is used to detect ESD events, then detection capability is provided, but false detections occur due to interference from signals with similar spectra
Solution Approach 1:
The patent extracts only the DC voltage component from the detected signal by using a low-pass filter to remove high-frequency components. This isolates the ESD event signature (DC voltage change) from interfering EMI signals that primarily contain high-frequency content, thereby eliminating false detections while maintaining ESD detection capability.
Solution Approach 2:
The patent introduces a capacitive coupling mechanism as an intermediary between the ESD event and the detection circuit. The capacitor integrates the fast ESD pulse into a measurable DC voltage level, serving as a mediator that converts the ESD event into a form that can be distinguished from high-frequency EMI interference through subsequent low-pass filtering.
2Reliability
If analog to digital sampling and digital signal processing are used to differentiate ESD events from EMI, then detection accuracy is improved, but power consumption increases
Solution Approach 1:
The patent replaces complex digital signal processing operations with simple analog circuit operations. Instead of using microprocessors to differentiate ESD from EMI, the system uses passive RC filtering and peak detection circuits that naturally perform the differentiation in the analog domain, dramatically reducing power consumption while maintaining detection accuracy.
Solution Approach 2:
The patent employs simple, low-cost analog components (resistors, capacitors, diodes) instead of expensive and power-hungry digital processing units. These passive components perform the signal differentiation function with minimal power consumption, making the system suitable for battery-powered applications.
3Measurement precision
If relatively long sampling time is used to detect each ESD event, then detection accuracy is improved, but the ability to recognize multiple successive events is lost
Solution Approach 1:
The patent uses a peak detection circuit that automatically captures the maximum voltage value during each ESD event and holds it for reading. This periodic sampling approach allows the system to accurately measure each event's peak amplitude while being ready to immediately detect the next event, enabling both precise measurement and high event rate detection.
Solution Approach 2:
The patent implements a peak hold circuit that preliminarily captures and stores the peak voltage value of each ESD event before the next event occurs. This preliminary action ensures that even if events occur in quick succession, each event's peak value is preserved and can be individually measured without requiring long sampling times.
4Measurement precision
If the second capacitive coupling discharges slowly through a high impedance path, then measurement accuracy is maintained, but discharge time becomes too long for continuous monitoring
Solution Approach 1:
The patent makes the discharge path impedance dynamic by using a controlled switch that changes the resistance value based on the measurement phase. During measurement, the switch opens to maintain high impedance for accuracy; after measurement, the switch closes to provide low impedance for rapid discharge, enabling continuous monitoring capability.
Solution Approach 2:
The patent implements periodic switching between high-impedance measurement mode and low-impedance discharge mode. The switch alternates between open and closed states, allowing the capacitive coupling to maintain voltage for accurate measurement during the open phase, then rapidly discharge during the closed phase, creating a cyclical measurement-discharge pattern that enables continuous event detection.
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 effectively distinguishes ESD events from noise, enables fast and accurate detection of multiple events, and reduces power consumption, making it suitable for continuous monitoring in portable battery-powered systems.
Implementation Method 1
a receiver for forming a first capacitive coupling with the object and a second capacitive coupling with a ground
Implementation Method 2
a first discharge path for discharging the second capacitive coupling to the ground
Implementation Method 3
The primary discharge path may include a resistor and the output voltage signal is arranged to discharge through the resistor
Implementation Method 4
The device may further comprise a low pass filter for blocking radio frequency signals of the output voltage signal to produce a filtered voltage signal
Implementation Method 5
The device may further comprise a peak detection circuit for outputting a peak voltage of the filtered voltage signal, the magnitude of the ESD event being determined based on the peak voltage
Data Source
AI summary
A device for detecting an electrostatic discharge event by an object, the device comprising: a receiver for forming a first capacitive coupling with the object and a second capacitive coupling with a ground; and a first discharge path for discharging the second capacitive coupling to the ground, such that an electrostatic discharge event by the object charges the second capacitive coupling by an amount in a first time interval Δt1 that is substantially less than a second time intervalΔt2 that it takes for the second capacitive coupling to discharge by the same amount through the first discharge path.