Iei-integration ICE-DB-9S Instrukcja Użytkownika Pobierz pdf (Strona 71)

ICE Module

Page 58

4.5.4 Over Current Protection

Over-current protection for USB ports can be implemented by using power distribution

switches on the carrier board that monitor the USB port power lines. Power distribution

switches usually have a soft-start circuitry that minimizes inrush current in applications

where highly capacitive loads are employed. Transient faults are internally filtered.

Additionally, they offer a fault status output that is asserted during over-current and

thermal shutdown conditions. These outputs should be connected to the

corresponding COM Express modules USB over-current sense signals. IEI uses

MIC2026 for carrier board.

Figure 4-23: MIC2026 Block Diagram(Please refer the datasheet from MICREL )

4.5.5 Reference Schematics

The following notes apply to Figure 4-24 below.

LAN_USB and CN26 incorporate two USB Type A receptacles, LAN_USB in addition

includes an RJ-45 (LANKom LJ -G40BU1-10-F).

The reference design uses an over-current detection and protection device. The Micrel

MIC2026 is dual channel power distribution switch. Power to the USB Port is filtered

using a ferrite (30 Ω @100MHz, 600mA) to minimize emissions. The ferrite should be

placed adjacent to the USB Port connector pins. The OC# signal is asserted until the

over-current or over-temperature condition is resolved.

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Iei-integration ICE-DB-9S Instrukcja Użytkownika Strona 71