GE Industrial Solutions 12V Mega TLynx - Manual (Page 13)

Data Sheet
May 4, 2012 12V Mega TLynx TM : Non-Isolated DC-DC Power Modules:
6.0 – 14Vdc Input; 0.8Vdc to 3.63Vdc Output; 30A output current
LINEAGE POWER 13
Vo
MODULE
GND
Trim
Q1
Rtrim
Rmargin-up
Q2
Rmargin-down
Figure 32. Circuit Configuration for margining
Output voltage.
Output Voltage Sequencing
The 12V Mega TLynx TM 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 final value of 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 basis.
By connecting multiple modules together, multiple
modules can 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
10msec delay is required before applying voltage
on the SEQ pin. This delay gives the module
enough time to complete its internal power-up soft-
start cycle. During the delay time, the SEQ pin
should be held close to ground (nominally 50mV ±
20 mV). This is required to keep the internal op-amp
out of saturation thus preventing output overshoot
during the start of the sequencing ramp. By
selecting resistor R1 (see fig. 33) according to the
following equation
05 . 0
24950
1
−
=
IN
V
R ohms,
the voltage at the sequencing pin will be 50mV
when the sequencing signal is at zero.
R1
GND
VIN+
SEQ
+
-
OUT
10K
499K
MODULE
Figure 33. Circuit showing connection of the
sequencing signal to the SEQ pin.
After the 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 the output reaches the set-point voltage.
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.
When using the EZ-SEQUENCE
TM feature to
control start-up of the module, pre-bias immunity
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 the voltage at
the SEQ pin is applied. This will result in the
module sinking current if a 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 the EZ-
SEQUENCE
TM feature please refer to Application
Note AN04-008 “Application Guidelines for Non-
Isolated Converters: Guidelines for Sequencing of
Multiple Modules”, or contact the Lineage Power
technical representative for additional information.
Active Load Sharing (-P Option)
For additional power requirements, the 12V Mega
TLynx
TM power module is also available with a
parallel option. Up to five modules can be
configured, in parallel, with active load sharing.