GE Industrial Solutions 40A Digital MegaDLynx - Manual (Page 13)

GE
Data Sheet
40A Digital MegaDLynx TM : Non-Isolated DC-DC Power Modules
4.5Vdc –14.4Vdc input; 0.45Vdc to 2.0Vdc output; 40A Output Current
April 24, 2013 ©2012 General Electric Company. All rights reserved. Page 13
10ms to ensure that the module output is ramped up
according to the sequencing signal. This ensures that the
module soft-start routine is completed before the sequencing
signal is allowed to ramp up.
Figure 26. Circuit showing connection of the sequencing
signal to the SEQ pin.
When the scaled down sequencing voltage is applied to the
SEQ pin, the output voltage tracks this voltage until the
output reaches the set-point voltage. The final value of the
sequencing voltage must be set higher than the set-point
voltage of the module. The output voltage follows the
sequencing voltage on a one-to-one basis. By connecting
multiple modules together, multiple modules can track their
output voltages to the voltage applied on the SEQ pin.
The module’s output can track the SEQ pin signal with slopes
of up to 0.5V/msec during power-up or power-down.
To initiate simultaneous shutdown of the modules, the SEQ
pin voltage is lowered in a controlled manner. The output
voltage of the modules tracks the voltages below their set-
point voltages on a one-to-one basis. A valid input voltage
must be maintained until the tracking and output voltages
reach ground potential.
Note that in all digital DLynx series of modules, the PMBus
Output Undervoltage Fault will be tripped when sequencing is
employed. This will be detected using the STATUS_WORD and
STATUS_VOUT PMBus commands. In addition, the
SMBALERT# signal will be asserted low as occurs for all faults
and warnings. To avoid the module shutting down due to the
Output Undervoltage Fault, the module must be set to
continue operation without interruption as the response to
this fault (see the description of the PMBus command
VOUT_UV_FAULT_RESPONSE for additional information).
Overcurrent Protection
To provide protection in a fault (output overload) condition,
the unit is equipped with internal current-limiting circuitry
and can endure current limiting continuously. At the point of
current-limit inception, the unit enters hiccup mode. The unit
operates normally once the output current is brought back
into its specified range.
Digital Adjustable Overcurrent Warning
Please see the Digital Feature Descriptions section.
Overtemperature Protection
To provide protection in a fault condition, the unit is equipped
with a thermal shutdown circuit. The unit will shut down if the
over temperature threshold of 145ºC(typ) is exceeded at the
thermal reference point T
ref
.Once the unit goes into thermal
shutdown it will then wait to cool before attempting to
restart.
Digital Temperature Status via PMBus
Please see the Digital Feature Descriptions section.
Digitally Adjustable Output Over and Under Voltage
Protection
Please see the Digital Feature Descriptions section.
Input Undervoltage Lockout
At input voltages below the input undervoltage lockout limit,
the module operation is disabled. The module will begin to
operate at an input voltage above the undervoltage lockout
turn-on threshold.
Digitally Adjustable Input Undervoltage Lockout
Please see the Digital Feature Descriptions section.
Digitally Adjustable Power Good Thresholds
Please see the Digital Feature Descriptions section.
Synchronization
The module switching frequency can be synchronized to a
signal with an external frequency within a specified range.
Synchronization can be done by using the external signal
applied to the SYNC pin of the module as shown in Fig. 27,
with the converter being synchronized by the rising edge of
the external signal. The Electrical Specifications table
specifies the requirements of the external SYNC signal. If the
SYNC pin is not used, the module should free run at the
default switching frequency. If synchronization is not being
used, connect the SYNC pin to GND.
MODULE
SYNC
GND
+
─
Figure 27. External source connections to synchronize
switching frequency of the module.
100 pF
DLynx Module
R1=Rtrim
20K
SIG_GND
SEQ
SEQ
V