Datasheet

Exponent
OUT(oc)
Mantissa
I Mantissa 2
2
= ´ =
TPS40400
www.ti.com SLUS930B –APRIL 2011– REVISED OCTOBER 2011
Exponent
–1 (dec), fixed
Mantissa
The upper five bits are fixed at 0.
Lower six bits are programmable with a default value of 15 (dec)
The actual output warning current level for a give mantissa and exponent is:
(22)
The default output fault current setting is 10A. Values of I
OUT(oc)
can range from 0A to 35A in 500mA increments.
The default output warning current setting is 7.5A.
OT_FAULT_RESPONSE (50h)
The OT_FAULT_RESPONSE command instructs the device on what action to take in response to an output over
temperature fault. The temperature sensed is the die temperature of the TPS40400 only. No other temperature
sensors are provided. The contents of this register can be stored to non-volatile memory using the
STORE_DEFAULT_ALL or STORE_DEFAULT_CODE commands. The OT_FAULT_LIMIT parameter is not
programmable and is therefore not supported in the PMBus command set. When an over temperature fault
condition is sensed, the device:
• Sets the TEMPERATURE bit in the STATUS_BYTE
• Sets the OT FAULT bit in the STATUS_TEMPERATURE register, and
• Notifies the host by asserting the SMBALRT signal
A one-byte unsigned binary data word is used with this command:
Command OT_FAULT_RESPONSE
Format Unsigned binary
Bit Position 7 6 5 4 3 2 1 0
Access r r/w r r r r r r
Function X OTF_RS X X X X X X
Default Value 1 1 0 0 0 0 0 0
OTF_RS
Over temperature fault retry setting
0: A zero value for the Retry setting indicates that the unit does not attempt to restart.
1: A one value for the Retry setting indicates that the unit goes through a normal startup (soft-start)
when the die temperature falls below the hysteresis band limit. (See the Electrical Characteristics
table).
POWER_GOOD_ON (5Eh)
The POWER_GOOD_ON command sets the value of the output voltage at which the PGOOD output pin (open
drain) is asserted high. The contents of this register can be stored to non-volatile memory using the
STORE_DEFAULT_ALL or STORE_DEFAULT_CODE commands. The actual implementation is a window
comparator with symmetrical thresholds above and below the nominal. This command sets both the upper and
lower power good threshold at the same time. The parameter passed with this command is always the lower
threshold (less than the nominal output) and is mapped to the closest supported percentages of the nominal
output voltage inTable 2.
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