PRM48BF480T500A00 Datasheet, PDF (38/45 Pages) Vicor Corporation – PRM™ Regulator

Arrays (Remote Sense operation)
In Remote Sense operation up to 10 PRMs of the same type
may be placed in parallel to expand the power capacity of the
system. All PRMs within the array are configured for Remote
Sense operation and are driven by an external control circuit
which considers the control inputs and drives the
CONTROL NODE bus. The following high-level guidelines
must be followed in order for the resultant system to start up
and operate properly, and to avoid overstress or exceeding
any absolute maximum ratings.
 All PRMs must be configured for Remote Sense
operation by tying TRIM pins to SGND. It is
recommended to make this connection through a 0Ω
jumper for troubleshooting purposes.
 All PRMs in the array must be powered from a
common power source so that the input voltage to
each PRM is the same.
 An independent fuse for each PRM +IN connection is
required to maintain safety certifications (see Fusing
section).
 An independent inductor for each PRM +IN connection
is recommended when used in an array, to control
circulating currents among the PRM inputs and reduce
the impact of beat frequencies.
 Mismatches in both inductance, and resistance from
the common power source to each PRM should be
minimized.
 ENABLE pins must be connected together for start up
synchronization and proper fault response of the array.
 Reference supply to the control loop voltage reference
and current sense circuitry must be enabled when all
modules’ REF_EN pins have reached their operational
voltage levels.
 A single external control circuit must be implemented
as described in the Remote Sense operation design
guidelines. The control circuit should drive the
CONTROL NODE bus.
 CONTROL NODE pins must be connected together to
enable sharing. The bandwidth requirements of
CONTROL NODE are low enough that the bus can be
considered a lumped element, rather than a
transmission line, and so star connections as well as
daisy chain connections are permitted.
 Each PRM must have its own local current shunt and
current sense circuitry to drive its IFB pin.
 The resistances between CONTROL NODE pins
should be well matched, to avoid introducing additional
PRM48B x 480 y 500A00
sharing mismatches. The CONTROL NODE bus
should not be routed under any PRM. Parasitic
capacitance to +IN or +OUT should be minimized.
 One PRM should be designated to provide the SGND
reference, VAUX, and REF_EN voltages for the
external circuitry.
 The SGND pins of all other PRMs should be
connected to the SGND reference node on the board
through a 1 Ω resistor.
 When operating within an array, the PRMs are de-
rated to the array rated power and current values
provided for Remote Sense operation (P_{OUT_ARRAY},
I_{OUT_ARRAY}). The number of PRMs required to achieve a
given array capacity must consider these de-ratings to
avoid overstressing any PRM in the array.
 When using VAUX to power external circuitry, total
current draw including CONTROL NODE sink currents
must be taken into account to ensure the maximum
VAUX current is not exceeded. Arrays of more than 5
PRMs may require additional circuitry to provide the
required source current. Contact Vicor Applications
Engineering for more information.
- 38 -
Rev. 1.0
11/2012