TPS65400_15 Datasheet, PDF (50/76 Pages) Texas Instruments – TPS65400 4.5- to 18-V Input Flexible Power Management Unit With PMBus/I2C Interface

TPS65400
SLVSCQ9B – NOVEMBER 2014 – REVISED SEPTEMBER 2015
www.ti.com
8.6.2.14 (DDh) TON_TOFF_DELAY
The TON_TOFF_DELAY command sets the delay times after receiving an on or off command for the selected
output to begin turning on or off.
TON_DELAY of this command are lexically equivalent to TON_DELAY. If TON_DELAY is set to 0 ms, the device
would begin turning on immediately. If TOFF_DELAY is set to 0 ms, the device would begin turning off
immediately.
BITS
7:6
5:3
NAME
—
TON_DELAY
2:0
TOFF_DELAY
Table 34. TON_TOFF_DELAY Data Byte Contents
READ /
WRITE
R
R/W
R/W
DEFAULT
VALUE
00
010
000
BINARY VALUE
—
000
001
010
011
100
101
110
111
000
001
010
011
100
101
110
111
VALUE
—
0 ms
1 ms
5 ms
25 ms
100 ms
500 ms
1000 ms
2000 ms
0 ms
1 ms
5 ms
25 ms
100 ms
500 ms
1000 ms
2000 ms
MEANING
—
Delay time before starting
Delay time before stopping
These delays are always in effect including when the outputs are internally or externally sequenced, or arbitrarily
turned on or off. The only exceptions are:
• The device receives an immediate OFF from the OPERATION command.
• The device turns its output off internally (such as in a fault condition).
PAGE support is for outputs 0x00 through 0x03.
8.6.2.15 (DEh) TON_TRANSITION_RATE
The TON_TRANSITION_RATE command sets the soft-start ramp rate for the selected output. This command is
ignored by default because soft-start is set externally through the SSx/PG pin. Only when the SSx/PG pin is
configured as PG through PIN_CONFIG_01 will TON_TRANSITION_RATE determine the soft-start rate.
The soft-start ramp rate refers to the rate at which the reference voltage is increased. The time to complete the
soft-start can be calculated from the target reference voltage as Equation 6.
t_ss

Soft
Vref
start ramp
rate
(6)
For example, if VREF is set to 0.6 V and the default soft-start ramp rate of 0.5 V/ms is selected, then the soft-
start time would be 1.2 ms. If VREF is set to 1 V and the soft-start ramp rate of 0.25 V/ms is selected, then the
soft-start time would be 4 ms.
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