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SLDM-06D1Ax

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47. PMBUS ADJUSTABLE OUTPUT OVER AND UNDER VOLTAGE PROTECTION

The module has output over and under voltage protection capability. The PMBus command VOUT_OV_FAULT_LIMIT is used to set the output

over voltage threshold from four possible values: 108%, 110%, 112% or 115% of the commanded output voltage. The command

VOUT_UV_FAULT_LIMIT sets the threshold that causes an output under voltage fault and can also be selected from four possible values: 92%,

90%, 88% or 85%. The default values are 112% and 88% of commanded output voltage. Both commands use two data bytes formatted as two’s

complement binary integers. The “Linear” mode is used with the exponent fixed to –10 (decimal) and the effective over or under voltage trip

points given by:

Values within the supported range for over and undervoltage detection thresholds will be set to the nearest fixed percentage. Note that the

correct value for VOUT_SCALE_LOOP must be set in the module for the correct over or under voltage trip points to be calculated.

In addition to adjustable output voltage protection, the 6A Digital module can also be programmed for the response to the fault. The

VOUT_OV_FAULT RESPONSE and VOUT_UV_FAULT_RESPONSE commands specify the response to the fault. Both these commands use a

single data byte with the possible options as shown below.



Continue operation without interruption (Bits [7:6] = 00, Bits [5:3] = xxx).



Continue for four switching cycles and then shut down if the fault is still present, followed by no restart or continuous restart (Bits [7:6] =

01, Bits [5:3] = 000 means no restart, Bits [5:3] = 111 means continuous restart).



Immediate shut down followed by no restart or continuous restart (Bits [7:6] = 10, Bits [5:3] = 000 means no restart, Bits [5:3] = 111 means

continuous restart).



Module output is disabled when the fault is present and the output is enabled when the fault no longer exists (Bits [7:6] = 11, Bits [5:3] =

xxx).

Note: that separate response choices are possible for output over voltage or under voltage faults.

48. PMBUS ADJUSTABLE INPUT UNDERVOLTAGE LOCKOUT

The SLDM-06D1Ax module allows adjustment of the input under voltage lockout and hysteresis. The command VIN_ON allows setting the input

voltage turn on threshold, while the VIN_OFF command sets the input voltage turn off threshold. For the VIN_ON command, possible values are

2.75V, and 3V to 14V in 0.5V steps. For the VIN_OFF command, possible values are 2.5V to 14V in 0.5V steps. If other values are entered for

either command, they will be mapped to the closest of the allowed values.

VIN_ON must be set higher than VINPMBUS _OFF. Attempting to write either VIN_ON lower than VIN_OFF or VIN_OFF higher than VIN_ON

results in the new value being rejected, SMBALERT being asserted along with the CML bit in STATUS_BYTE and the invalid data bit in

STATUS_CML.

Both the VIN_ON and VIN_OFF commands use the “Linear” format with two data bytes. The upper five bits represent the exponent (fixed at -2)

and the remaining 11 bits represent the mantissa. For the mantissa, the four most significant bits are fixed at 0.

10

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LIMIT

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REQ

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