SMH4811 Ver la hoja de datos (PDF) - Summit Microelectronics

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componentes Descripción

Fabricante

SMH4811

Distributed Power Hot-Swap Controller

Summit Microelectronics 

SMH4811A

Figure 4

The 2.5Vref and 5Vref outputs are used to support the

peripheral circuits. In this example ENPG is pulled high to

the self-generated 5VREF.

The U1 circuitry is a temperature sensor that is effectively

a safety shut down circuit tied into the EN/TS input. If the

LMV331 drives its output low it will immediately turn off the

VGATE output.

The physical implementation of the board pins (see Note

2.) ensures the add-in card has power to the SMH4811,

but power to the backend circuits cannot be turned on until

the card is properly seated.

Figure 5

The polarity of the PG# output is reversed. EN/TS and

ENPG are under the control of the host system.

Figure 6

A circuit for controlling a DC/DC converter with a remote

off/on function. It should be noted the board layout for the

DC/DC converters is critical for proper operation. Most

manufacturers will have detailed technical notes to assist

with this. An excellent note is “Application Guidelines for

On-Board Power Converters” from Lucent Technologies.

Figure 7

A circuit for controlling a dual DC/DC converter with a

remote off/on function.

Note: Pin detect inputs must be connected to the

–48V input when the card is inserted, not to the 0V

input.

48V

RD

PD1# VDD

EN/TS

CBFAULT#

PG

1N4148

PG#

MM6T-

A06LT1

ENPG

EN/TS

47kΩ

R3

UV

SMH4811A

25.50VREF

R2

OV

R1

PD2# VSS CBSENSE VGATE

DRAIN

SENSE

100nF

25V

0V

1kΩ

100nF

20mΩ

10Ω RV*

10nF

100nF

1kΩ

1N4148

100nF

100V

4.7µF

100V

Figure 5. Generic Hot Swap implementation

SUMMIT MICROELECTRONICS, Inc.

2044 4.1 8/1/00

11

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