NVMe Connector Pin Length Layout for Accurate Hot-Swap Detection
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Solution Overview
Problem
NVMe storage devices face issues with successful system access when removed and inserted due to inaccurate in-service signal reflection caused by unequal lengths of pins for in-service, power supply, clock, and PCIe port signals in SFF-8639 connectors.
Innovation Solution
Modifying the lengths of pins in the connector to ensure equal lengths for in-service, power supply, clock, and PCIe port signals, or making the in-service signal pin length not greater than the others, to accurately reflect the state of the NVMe storage device during insertion or removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pin lengths in the SFF-8639 connector are unequal with the in-service signal pin (P4) being the longest, then the contact sequence is defined (P4 contacts first), but the in-service signal cannot accurately reflect the actual state of the NVMe storage device during hot-swapping operations
Solution Approach 1:
The patent changes the length parameter of the in-service signal pin (P4) from being the longest pin to being equal in length to or shorter than other signal pins. This parameter change ensures that P4 does not make contact first during insertion, allowing other critical signals (power supply, clock, PCIe port) to establish contact before the in-service signal activates, thereby accurately reflecting the actual operational state of the NVMe storage device
2Ease of operation
If the pin P4 is made longer to ensure first contact for in-service signal detection, then the contact sequence is established, but the system cannot successfully detect the NVMe storage device during hot-swapping operations
Solution Approach 1:
The patent inverts the conventional approach by making the in-service signal pin (P4) equal in length to or shorter than other signal pins instead of longer. This inversion ensures that critical operational signals establish contact before the in-service signal, allowing the system to properly detect and initialize the NVMe storage device during hot-swapping operations
3Reliability
If all pins in the connector are made equal in length, then the contact sequence becomes simultaneous, but the in-service signal can accurately reflect the NVMe storage device state during insertion and removal
Solution Approach 1:
The patent applies parameter changes by standardizing the length of pin P4 to be equal to or shorter than other signal pins, transforming the contact sequence from sequential (P4 first) to simultaneous or delayed. This simple parameter change resolves the hot-swapping detection issue without significantly increasing connector design complexity
Data Source
AI summary
A connector includes a first pin which is configured to indicate an in-service signal, a second pin which is configured to indicate a power supply signal, a third pin which is configured to indicate a clock signal, and a fourth pin; the first pin which is configured to indicate a PCIe port signal; the first pin, the second pin, the third pin, and the fourth pin have an equal length; and the connector includes a first face and a second face, a limiting structure is arranged on the first face, the limiting structure is a boss or a groove, and the first pin is located in the middle of the first face.