SLDM-06D1Ax

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Rev. AC

49. POWER GOOD

The SLDM-06D1Ax module provides a Power Good (PGOOD) signal that is implemented with an open-drain output to indicate that the output

voltage is within the regulation limits of the power module. The PGOOD signal will be de-asserted to a low state if any condition such as

overtemperature, overcurrent or loss of regulation occurs that would result in the output voltage going outside the specified thresholds. The

PGOOD thresholds are user selectable via the PMBus (the default values are as shown in the Feature Specifications Section). Each threshold is

set up symmetrically above and below the nominal value. The POWER_GOOD_ON command sets the output voltage level above which PGOOD

is asserted (lower threshold). For example, with a 1.2V nominal output voltage, the POWER_GOOD_ON threshold can set the lower threshold to

1.14 or 1.1V. Doing this will automatically set the upper thresholds to 1.26 or 1.3V.

The POWER_GOOD_OFF command sets the level below which the PGOOD command is de-asserted. This command also sets two thresholds

symmetrically placed around the nominal output voltage. Normally, the POWER_GOOD_ON threshold is set higher than the

POWER_GOOD_OFF threshold.

Both POWER_GOOD_ON and POWER_GOOD_OFF commands use the “Linear” format with the exponent fixed at –10 (decimal). The two

thresholds are given by

Both commands use two data bytes with bit [7] of the high byte fixed at 0, while the remaining bits are r/w and used to set the mantissa using

two’s complement representation. Both commands also use the VOUT_SCALE_LOOP parameter so it must be set correctly. The default value of

POWER_GOOD_ON is set at 1.1035V and that of the POWER_GOOD_OFF is set at 1.08V. The values associated with these commands can

be stored in non-volatile memory using the STORE_DEFAULT_ALL command.

The PGOOD terminal can be connected through a pullup resistor(suggested value 100 K) to a source of 5VDC or lower.

50. MEASURREMENT OF OUTPUT CURRENT, OUTPUT VOLTAGE AND INPUT VOLTAGE

The SLDM-06D1Ax module is capable of measuring key module parameters such as output current and voltage and input voltage and providing

this information through the PMBus interface. Roughly every 200μs, the module makes 16 measurements each of output current, voltage and

input voltage. Average values of of these 16 measurements are then calculated and placed in the appropriate registers. The values in the

registers can then be read using the PMBus interface.

10

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10

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2

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2

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OFF

GOOD

POWER

V

ON

GOOD

POWER

V

OFF

PGOOD

OUT

ON

PGOOD

OUT