ltc2978 Linear Technology Corporation, ltc2978 Datasheet - Page 15

• Manufacturer Part Number: ltc2978
• Description: Octal Pmbus Power Supply Monitor And Controller With Eeprom
• Manufacturer: Linear Technology Corporation

OPERATION OVERVIEW
The LTC2978 is a PMBus programmable power supply
controller, monitor, sequencer and voltage supervisor that
can perform the following operations:
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operaTion
Accept PMBus compatible programming commands.
Provide DC/DC converter input voltage and output volt-
age/current read back through the PMBus interface.
Control the output of modules that set voltage with a
trim pin or modules that set the output voltage using
an external resistor feedback network.
Sequence the start-up of DC/DC converters via PMBus
programming and the CONTROL input pins.
Trim the DC/DC converter output voltage (typically in
0.1% steps), in closed-loop servo operating mode,
through PMBus programming.
Margin the DC/DC converter output voltage to PMBus
programmed limits (typically ±10%).
Allow the user to trim or margin the DC/DC converter
output voltage in a manual operating mode by providing
direct access to the margin DAC.
Supervise the DC/DC converter output voltage, input
voltage, and the LTC2978 die temperature for over-
value/undervalue conditions with respect to PMBus
programmed limits and generate appropriate faults and
warnings.
Respond to a fault condition by either continuing op-
eration indefinitely, latching off after a programmable
de-glitch period or latching off immediately. A retry
mode may be used to automatically recover from a
latched-off condition.
Stop trimming the DC/DC converter output voltage after
it reached the initial margin or nominal target. Optionally
allows servo to resume if target drifts outside of V
warning limits.
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Store command register contents to EEPROM through
PMBus programming.
Restore EEPROM contents through PMBus program-
ming or on POR.
Report the DC/DC converter output voltage status
through the PMBus interface and the power good
output.
Generate interrupt requests by asserting the ALERTB
pin in response to supported PMBus faults.
Shut down multiple DC/DC converters in response to
a fault through the FAULTBz0 and FAULTBz1 pins.
Synchronize sequencing delays or shutdown for multiple
devices using the SHARE_CLK pin.
Software and hardware write protect the command
registers.
Disable the input voltage to the supervised DC/DC
converters in response to output voltage OV and UV
faults.
Log telemetry and status data to EEPROM in response
to a faulted-off condition
Supervise an external microcontroller’s activity for a
stalled condition with a programmable watchdog timer
and reset it if necessary.
Prevent a DC/DC converter from re-entering the ON
state after a power cycle until a programmable interval
(MFR_RESTART_DELAY) has elapsed and its output
has decayed below a programmable threshold voltage
(MFR_VOUT_DISCHARGE_THRESHOLD).
Record minimum and maximum observed values of
input voltage, output voltages and temperature.
LTC2978

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