Active EMI Probe Amplifier Reduces Insertion Loss
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Solution Overview
Problem
Passive EMI probes face significant loss and are unable to detect high-frequency interference due to large impedance, leading to measurement challenges and time-consuming processes, especially in IC-level testing where signal amplitudes are small and noise levels are high.
Innovation Solution
An active measuring probe with a 1Ω resistor and integrated amplifier is designed, reducing insertion loss and enhancing noise detection ability by incorporating a first connecting member, impedance element, and amplifier, allowing for lower loss and improved detection of high-frequency interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive 1Ω current probe is used for EMI measurement, then the measurement complies with IEC standards, but the insertion loss is large (34 dB) and the voltage amplitude is very small
Solution Approach 1:
An active probe head is introduced as an intermediary component between the passive current probe and the measurement system. This active probe head contains an amplifier that compensates for the signal loss, effectively mediating between the low-voltage output of the passive probe and the requirements of the measurement system.
Solution Approach 2:
The system changes the voltage level parameter by introducing amplification. The passive probe maintains its 1Ω compliance while the active probe head amplifies the voltage signal, transforming the parameter from low voltage (after passive probe) to sufficient voltage level (after amplification) for accurate measurement.
2Measurement precision
If the resolution bandwidth is set to very narrow to measure low-voltage interference signals, then the measurement precision improves, but the measurement time becomes extremely long
Solution Approach 1:
The amplifier changes the voltage level parameter of the signal, which allows the use of wider bandwidth settings without losing detection capability. By amplifying weak signals before measurement, the system can achieve good detection results with faster measurement times.
3Speed
If multiple resistors are connected in parallel to build a 1 GHz bandwidth current probe, then the frequency response is improved, but the parasitic effect remains and the loss is still large
Solution Approach 1:
The active probe head serves as an intermediary that compensates for the limitations of the passive current probe. While the passive probe provides frequency response through parallel resistor configuration, the active probe head amplifies the signal to overcome the parasitic losses inherent in the passive design.
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 active probe achieves reduced insertion loss and superior noise detection, enabling the measurement of high-frequency interference within a reasonable time, suitable for large-scale production testing and IC-level assessments.
Implementation Method 1
an active measuring probe with integrated amplifier for measuring EMI in giga hertz... By the integration of accurate resistor design and amplifier, the loss of the measuring probe can be lower than 34 dB
Data Source
AI summary
The present invention relates to an active measuring probe for EMI detection comprising a first connecting member, an impedance element, an amplifier and a second connecting member. The first connecting member is coupled to one terminal of the impedance element and an input terminal of the amplifier. The other terminal of the impedance element is coupled to a ground terminal. The second connecting member is coupled to an output terminal of the amplifier.