BC384A480T033FP Datasheet, PDF (12/16 Pages) Vicor Corporation – BCM Bus Converter

CONTROL FUNCTION / FUSING
Using the Control Signals TM and PC
The PC control pin can be used to accomplish the following
functions:
• Delayed start: At start-up, PC pin will source a constant
100 uA current to the internal RC network. Adding an
external capacitor will allow further delay in reaching the
2.5 V threshold for module start.
• Synchronized start up: In a parallel module array, PC pins
shall be connected in order to ensure synchronous start of all
the units. While every controller has a calibrated 2.5 V
reference on PC comparator, many factors might cause
different timing in turning on the 100 uA current source on
each module, i.e.:
– Different V_IN slew rate
– Statistical component value distribution
By connecting all PC pins, the charging transient will be
shared and all the modules will be enabled synchronously.
• Auxiliary voltage source: Once enabled in regular
operational conditions (no fault), each BCM PC provides a
regulated 5 V, 2 mA voltage source.
• Output Disable: PC pin can be actively pulled down in order
to disable module operations. Pull down impedance shall be
lower than 850 Ω and toggle rate lower than 1 Hz.
• Fault detection flag: The PC 5 V voltage source is internally
turned off as soon as a fault is detected. After a minimum
disable time, the module tries to re-start, and PC voltage is
re-enabled. For system monitoring purposes (microcontroller
interface) faults are detected on falling edges of PC signal.
It is important to notice that PC doesn’t have current sink
capability (only 150 kΩ typical pull down is present),
therefore, in an array, PC line will not be capable of disabling
all the modules if a fault occurs on one of them.
The temperature monitor (TM) pin provides a voltage proportional to the
absolute temperature of the converter control IC.
It can be used to accomplish the following functions:
• Monitor the control IC temperature: The temperature in
Kelvin is equal to the voltage on the TM pin scaled
by x100. (i.e. 3.0 V = 300 K = 27ºC). It is important to
remember that VI BRICKs are multi-chip modules, whose
temperature distribution greatly vary for each part number as
well with input/output conditions, thermal management and
environmental conditions. Therefore, TM cannot be used to
thermally protect the system.
• Fault detection flag: The TM voltage source is internally
turned off as soon as a fault is detected. After a minimum
disable time, the module tries to re-start, and TM voltage is
re-enabled.
PRELIMINARY DATASHEET
Fuse Selection
VI BRICKs are not internally fused in order to provide flexibility in configur-
ing power systems. Input line fusing of VI BRICKs is recommended at sys-
tem level, in order to provide thermal
protection in case of catastrophic failure.
The fuse shall be selected by closely matching system
requirements with the following characteristics:
• Current rating (usually greater than maximum BCM current)
• Maximum voltage rating (usually greater than the maximum
possible input voltage)
• Ambient temperature
• Nominal melting I²t
• Recommended fuse: ≤2.5 A Bussmann PC-Tron or
SOC type 36CFA.
Bus Converter Module
BC384A480T033FP
vicorpower.com
Rev. 1.0
Page 12 of 16