Master Channel - Linear Technology DC1978A Manual

COMMON DEMO BOARD OPERATIONS
when the master is down requires supervisors monitoring
the slaves to disable UV detection. Slave UC detection must
also be disabled when the slaves are tracking the master
down to prevent false UC events. All channels configured
for tracking must track off together in response to a fault
on any channel or any other condition that can bring one
or more of the channels down. Prematurely disabling a
slave channel via its run pin may cause that channel to
shut down out of sequence. The LTC2974 supports the
following tracking features:
• Track channels on and off without issuing false UV/
UC events when the slave channels are tracking up or
down.
• Track all channels down in response to a fault from a
slave or master.
• Track all channels down when V
VIN_OFF , share clock is held low or RESTORE_USER_
ALL is issued.
CONTROL0
FAULTB0
Figure 6. LTC2974 Configured to Control, Supervise and Monitor Power Supplies Equipped with Tracking Pin
drops below
IN_SNS
LTC2974
CONTROL0 PWRGD
FAULTB0
V V
SENSEP0 OUT_EN0
V V
SENSEM0 DAC0
V V
SENSEP1 OUT_EN1
V V
SENSEM1 DAC1
R1_1
V V
SENSEP2 OUT_EN2
V V
SENSEM2 DAC2
R1_2
V V
SENSEP3 OUT_EN3
V V
SENSEM3 DAC3
R1_3
DEMO MANUAL DC1978A
• Ability to reconfigure selected channels that are part of
a tracking group to sequence up after the group has
tracked up or sequence down before the group has
tracked down.
To demonstrate the tracking features of LTC2974, DC1810A
has three jumpers (JP1, JP2 and JP3) that can be set to
connect resistive dividers from the 1.8V master supply
(CH0) to the TRACK pins of channels 1 to 3.
The required timing settings and diagrams in order to
enable tracking with LTC2974 are listed in the data sheet,
and a brief summary is shown below:

Master channel 0

• TON_DELAY = Ton_delay_master
• TON_RISE = Ton_rise_master
• TOFF_DELAY = Toff_delay_master
• Mfr_track_en_chan0 = 0
RUN V
OUTP
V DC/DC
FB
TRACK V
OUTM
RUN V
OUTP
V DC/DC
FB
TRACK V
OUTM
R2_1
RUN V
OUTP
V DC/DC
FB
TRACK V
OUTM
R2_2
RUN V
OUTP
V
DC/DC
FB
TRACK V
OUTM
R2_3
V
SENSEP0
LOAD
V
SENSEM0
V
SENSEP1
LOAD
V
SENSEM1
V
SENSEP2
LOAD
V
SENSEM2
V
SENSEP3
LOAD
V
SENSEM3
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