Relay Pogo CDM Tester for Repeatable ESD Testing
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Solution Overview
Problem
Current Field Induced Charged Device Model (FICDM) testers face repeatability issues due to variable spark resistance in air discharge, leading to challenges in standardizing CDM testing, especially at lower voltages, and the contact-first method (CCDM) introduces impedance differences affecting waveform measurements.
Innovation Solution
The RP-CCDM test head apparatus incorporates a wetted reed switch relay between the pogo pin and current sensing element, ensuring consistent contact and using a multi-conductive ground plane geometry to maintain accurate field-induced charging while allowing for relay-based contact-first CDM testing, enabling consistent and repeatable measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Field Induced CDM (FICDM) testing method is used to simulate true CDM events, then measurement accuracy is improved, but repeatability deteriorates due to variable spark resistance
Solution Approach 1:
The patent introduces a relay switch as an intermediary component between the high voltage source and the CDM device. This relay acts as a mediator that controls the timing and path of the high voltage pulse, allowing the system to maintain the field-induced charging mechanism while providing consistent, repeatable measurement conditions through controlled switching.
Solution Approach 2:
The patent applies preliminary charging to the relay capacitor before the actual CDM event. By pre-charging the relay capacitor to the desired voltage level and then rapidly discharging it through the CDM device via the relay switch, the system establishes consistent initial conditions that improve repeatability while maintaining measurement accuracy.
2Reliability
If Contact-First CDM (CCDM) method is used to eliminate spark resistance variability, then repeatability is improved, but measurement accuracy deteriorates due to impedance differences
Solution Approach 1:
The patent changes the electrical parameters by introducing a controlled high voltage pulse through the relay switch, transforming the measurement approach from direct contact charging to pulse-induced field charging. This parameter change allows the system to achieve both repeatable conditions and accurate measurements by controlling the voltage pulse characteristics.
Solution Approach 2:
The patent replaces the mechanical contact-first charging mechanism with an electrically-controlled field-induced charging mechanism using the relay switch. This substitution eliminates the mechanical contact variability while maintaining consistent electrical conditions, thereby improving both repeatability and measurement accuracy.
3Stability of the object's composition
If traditional FICDM test head structure is used, then field-induced charging mechanism is maintained, but mechanical jitter occurs during pogo pin contact
Solution Approach 1:
The relay switch serves as an intermediary that decouples the mechanical contact process from the electrical charging process. By using the relay to control the high voltage pulse delivery separately from the pogo pin contact, the system maintains the field-induced charging mechanism while eliminating the mechanical jitter that occurs during direct contact.
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 provides highly consistent and repeatable CDM testing by minimizing mechanical jitter and maintaining accurate field-induced charging mechanisms, replicating real-world CDM events with improved repeatability and adherence to standards like ANSI/ESDA/JEDEC JS-002.
Implementation Method 1
The present invention utilizes a wetted reed switch relay located directly between the pogo pin and the current sensing element of the CDM test head apparatus. The wetted relay internal contacts ensure an exceptionally consistent contact surface with minimal bouncing of physical contacts due to the impact of connection
Implementation Method 2
The metal plate, referred to as a charge plane, is given a high voltage potential which in combination with the ground plane of the test head apparatus creates a strong electric field under which the device becomes capacitively charged
Implementation Method 3
The device becomes charged by either electric field charging, in which electric fields near the device cause the voltage potential of the device to change without changing its net charge
Data Source
AI summary
A relay pogo contact first charged device model test head apparatus for relay-based contact first field induced charged device model testing has a ground plane of conductive material, a coaxial connector whose outer conductor electrically connects to the ground plane, a current-sensing element with one terminal electrically connects to the ground plane and the other terminal electrically connects to the center conductor of the coaxial connector, a switch where the first terminal electrically connects to a center conductor of the coaxial connector, and a probe with one end electrically connected to a second terminal of the switch and the other end exposed to contact external objects.