TPS544C25 Datasheet, PDF (40/100 Pages) Texas Instruments – 4.5-V to 18-V, 20-A and 30-A SWIFT Synchronous Buck Converters with PMBus and Frequency Synchronization

TPS544C25, TPS544B25
SLUSC81 – MAY 2015
www.ti.com
COMMAND
OPERATION
Format
Unsigned binary
Bit Position
7
6
5
4
3
2
1
0
Access
r/w
r/w
r
r
r
r
r
r
Function
ON
OFF
X
X
X
X
X
X
Default Value
0
0
X
X
X
X
X
X
7.6.1.1 On
This bit is an enable command to the converter.
• 0: output switching is disabled. Both drivers placed in an off or low state.
• 1: output switching is enabled if the input voltage is above undervoltage lockout, OPERATION is configured
as a gating signal in ON_OFF_CONFIG, and no fault conditions exist.
7.6.1.2 Off
This bit sets the turn-off behavior when commanding the unit to turn off via OPERATION[7] ( the “ On“ bit).
• 0: Immediately turn off the output (not honoring the programmed turn-off delay (TOFF_DELAY) and ramp
down (TOFF_FALL)) when commanded off via OPERATION[7] ( the “ On“ bit).
• 1: Use the programmed turn-off delay (TOFF_DELAY) and ramp down (TOFF_FALL) when commanded off
via OPERATION[7] – aka “soft off”.
NOTE
The device ignores any values written to read-only bits. Additionally, both “on” and “off”
bits being set at the same time is not allowed and considered invalid data per section 12.1
of the PMBus Specification Part II; any attempt to do so causes the device to set the ’cml’
bit in the STATUS_BYTE and the ‘ivd’ bit in the STATUS_CML registers, and triggers
SMBALERT signal.
7.6.2 ON_OFF_CONFIG (02h)
The ON_OFF_CONFIG command configures the combination of CNTL pin input and serial bus commands
needed to turn the unit on and off. The contents of this register can be stored to non-volatile memory using the
STORE_DEFAULT_ALL (11h) command. The default value in ON_OFF_CONFIG register is to have the device
power up by CNTL pin only with the active high polarity and use the programmed turn-off delay (TOFF_DELAY)
and ramp down (TOFF_FALL) for powering off the converter.
COMMAND
ON_OFF_CONFIG
Format
Unsigned binary
Bit Position
Access
7
6
5
4
3
2
1
0
r
r
r
r/w^E
r/w^E
r/w^E
r/w^E
r/w^E
Function
X
X
X
pu
cmd
cpr
pol
cpa
Default Value
X
X
X
1
0
1
1
0
7.6.2.1 pu
The pu bit sets the default to either operate any time power is present or for power conversion to be controlled by
CNTL pin and PMBus OPERATION command. This bit is used in conjunction with the 'cpr', 'cmd', and 'on' bits to
determine start up.
BIT VALUE
0
1
ACTION
Device powers up any time power is present regardless of state of the CNTL pin.
Device does not power up until commanded by the CNTL pin and/or OPERATION
command as programmed in bits [3:0] of the ON_OFF_CONFIG register.
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