SLDN-03D1Ax

21

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© 2019 Bel Power Solutions & Protection

Rev. D1.04.19

interfering with other system operations. Both 100kHz and 400kHz bus speeds are supported by the module. Connection for the Power

Management Bus interface should follow the High Power DC specifications given in section 3.1.3 in the SMBus specification V2.0 for

the 400kHz bus speed or the Low Power DC specifications in section 3.1.2. The complete SMBus specification is available from the

SMBus web site, smbus.org.

ADDR0

SIG_GND

ADDR1

Figure 48. Circuit showing connection of resistors used to set the Power Management Bus address of the module.

The SLDN-03D1Ax module can also be turned on and off via the Power Management Bus interface. The OPERATION command is

used to actually turn the module on and off via the Power Management Bus, while the ON_OFF_CONFIG command configures the

combination of analog ON/OFF pin input and Power Management Bus commands needed to turn the module on and off. Bit [7] in the

OPERATION command data byte enables the module, with the following functions:

0

:

Output is disabled

1

:

Output is enabled

This module uses the lower five bits of the ON_OFF_CONFIG data byte to set various ON/OFF options as follows:

Bit Position

4

3

2

1

0

Access

r/w

r/w

r/w

r/w

r

Function

PU

CMD

CPR

POL

CPA

Default Value

1

0

1

1

1

PU: Sets the default to either operate any time input power is present or for the ON/OFF to be controlled by the analog ON/OFF input

and the Power Management Bus OPERATION command. This bit is used together with the CP, CMD and ON bits to determine startup.

Bit Value

Action

0

Module powers up any time power is present regardless of state of the analog ON/OFF pin

1

Module does not power up until commanded by the analog ON/OFF pin and the OPERATION

command as programmed in bits [2:0] of the ON_OFF_CONFIG register.

CMD: The CMD bit controls how the device responds to the OPERATION command.

Bit Value

Action

0

Module ignores the ON bit in the OPERATION command

1

Module responds to the ON bit in the OPERATION command

CPR: Sets the response of the analog ON/OFF pin. This bit is used together with the CMD, PU and ON bits to determine startup.

Bit Value

Action

0

Module ignores the analog ON/OFF pin, i.e. ON/OFF is only controlled through the Power

Management Bus via the OPERATION command

1

Module requires the analog ON/OFF pin to be asserted to start the unit