Linear Technology Analog Devices LTC3882-1, Техническое описание

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LTC3882-1
83
Rev A
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These commands can be used to establish required on/off sequencing for any number of system power supply rails.
MFR_RESTART_DELAY
The MFR_RESTART DELAY command specifies the minimum PWM off time (RUN low) in milliseconds. The LTC3882-1
will actively hold its RUN pin low for this length of time if a falling RUN edge is detected. After this delay, a standard
start-up sequence can be initiated. A minimum of TOFF TOF 136ms is recommended for this com-
mand value. Valid value range is 136ms to 65.52 seconds. The LTC3882-1 uses a resolution of 16ms for this command
and will not produce delays outside of this range.
This command has two data bytes in Linear_5s_11s format.
TON_DELAY
The TON_DELAY command sets the delay, in milliseconds, between a start condition and the beginning of the output
voltage rise. Values from 0ms to 83 seconds are considered valid, and the LTC3882-1 will not produce delays outside
of this range.
This command has two data bytes in Linear_5s_11s format.
TON_RISE
The TON_RISE command sets the desired time, in milliseconds, from the point the output starts to rise until it enters
the regulation band. Values from 0 seconds to 1.3 seconds are considered valid, and the LTC3882-1 will not produce
rise times outside of this range. Values of TON_RISE less than 0.25ms or resulting slopes greater than 4V/ms will
result in an output step to the commanded voltage limited only by PWM analog loop response.
This command has two data bytes in Linear_5s_11s format.
OUTPUT TIMING, DELAYS, AND RAMPING
COMMAND NAME
CMD
CODE DESCRIPTION TYPE PAGED
DATA
FORMAT UNITS NVM
DEFAULT
VALUE
MFR_RESTART_DELAY 0xDC Minimum time RUN pin is held low by the
LTC3882-1.
R/W Word Y L11 ms
l
500ms
0xFBE8
TON_DELAY 0x60 Delay from RUN pin or OPERATION on
command to TON_RISE ramp start.
R/W Word Y L11 ms
l
0.0ms
0x8000
TON_RISE 0x61 Time for V
OUT
to rise from 0V to
VOUT_COMMAND after TON_DELAY.
R/W Word Y L11 ms
l
8.0ms
0xD200
TON_MAX_FAULT_LIMIT 0x62 Maximum time for V
OUT
to rise above
VOUT_UV_FAULT_LIMIT after TON_DELAY.
R/W Word Y L11 ms
l
10.0ms
0xD280
VOUT_TRANSITION_RATE 0x27 V
OUT
slew rate for programmed output
changes.
R/W Word Y L11 V/ms
l
0.25V/ms
0xAA00
TOFF_DELAY 0x64 Delay from RUN pin or OPERATION off
command to TOFF_FALL ramp start.
R/W Word Y L11 ms
l
0.0ms
0x8000
TOFF_FALL 0x65 Time for V
OUT
to fall to 0V from
VOUT_COMMAND after TOFF_DELAY.
R/W Word Y L11 ms
l
8.0ms
0xD200
TOFF_MAX_WARN_LIMIT 0x66 Maximum time for V
OUT
to decay below
12.5% of VOUT_COMMAND after TOFF_FALL
completes.
R/W Word Y L11 ms
l
150ms
0xF258
Related commands: MFR_RETRY_DELAY, STATUS_VOUT, SMBALERT_MASK, TON_MAX_FAULT_RESPONSE, MFR_CHAN_CONFIG_LTC3882-1,
MFR_PWM_MODE_LTC3882-1
PMBus COMMAND DETAILS
(Output Timing, Delays, and Ramping)