GE Industrial Solutions Austin Microlynx II SMT - Manual (Page 14)

Data Sheet
September 10, 2013 Austin MicroLynx TM II SMT Non-isolated Power Modules:
2.4 – 5.5Vdc input; 0.75Vdc to 3.63Vdc Output; 6A output current
LINEAGE POWER 14
Feature Descriptions (continued)
Voltage Sequencing
Austin MicroLynx TM II series of modules include a
sequencing feature, EZ-SEQUENCE TM that enables
users to implement various types of output voltage
sequencing in their applications. This is accomplished
via an additional sequencing pin. When not using the
sequencing feature, either tie the SEQ pin to V
IN
or leave
it unconnected.
When an analog voltage is applied to the SEQ pin, the
output voltage tracks this voltage until the output reaches
the set-point voltage. The SEQ voltage must be set
higher than the set-point voltage of the module. The
output voltage follows the voltage on the SEQ pin on a
one-to-one volt basis. By connecting multiple modules
together, customers can get multiple modules to track
their output voltages to the voltage applied on the SEQ
pin.
For proper voltage sequencing, first, input voltage is
applied to the module. The On/Off pin of the module is
left unconnected (or tied to GND for negative logic
modules or tied to V
IN
for positive logic modules) so that
the module is ON by default. After applying input voltage
to the module, a minimum of 10msec delay is required
before applying voltage on the SEQ pin. During this time,
potential of 50mV (± 10 mV) is maintained on the SEQ
pin. After 10msec delay, an analog voltage is applied to
the SEQ pin and the output voltage of the module will
track this voltage on a one-to-one volt bases until output
reaches the set-point voltage. To initiate simultaneous
shutdown of the modules, the SEQ pin voltage is lowered
in a controlled manner. 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 to ensure a controlled shutdown of the
modules.
When using the EZ-SEQUENCE
TM feature to control
start-up of the module, pre-bias immunity feature during
start-up is disabled. The pre-bias immunity feature of the
module relies on the module being in the diode-mode
during start-up. When using the EZ-SEQUENCE
TM
feature, modules goes through an internal set-up time of
10msec, and will be in synchronous rectification mode
when voltage at the SEQ pin is applied. This will result in
sinking current in the module if pre-bias voltage is present
at the output of the module. When pre-bias immunity
during start-up is required, the EZ-SEQUENCE
TM feature
must be disabled. For additional guidelines on using EZ-
SEQUENCE
TM feature of Austin MicroLynx TM II , contact
Lineage Power technical representative for preliminary
application note on output voltage sequencing using
Austin Lynx II series.