GE Industrial Solutions TLynx - Manual (Page 15)

Data Sheet
August 13, 2013 TLynx TM : Non-isolated DC-DC Power Modules:
2.4 – 5.5Vdc input; 0.6Vdc to 3.63Vdc output; 20A output current
LINEAGE POWER 15
Vo
MODULE
GND
Trim
Q1
Rtrim
Rmargin-up
Q2
Rmargin-down
Figure 42. Circuit Configuration for margining
Output voltage
Monotonic Start-up and Shutdown
The TLynx TM modules have monotonic start-up and
shutdown behavior for any combination of rated input
voltage, output current and operating temperature
range.
Output Voltage Sequencing
The APTH020A0X modules include a sequencing
feature, EZ-SEQUENCE 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 volt 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.
During this time, a voltage of 50mV (± 20 mV) must be
maintained on the SEQ pin. This can be done by
applying the sequencing voltage through a resistor
R1connected in series with the SEQ pin as shown in
Figure 40. By choosing R1 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 43. 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.