GE Data Sheet
12V TLynxTM 20A: Non-Isolated DC-DC Power Modules
4.5Vdc –14Vdc input; 0.69Vdc to 5.5Vdc output; 20A Output Current
December 5, 2019 ©2017 General Electric Corporation. All rights
reserved. Page 16
POL Programming Tool, available at www.lineagepower.com under
the Design Tools section, also calculates the values of Rmargin-up and
Rmargin-down for a specific output voltage and % margin. Please
consult your local Lineage Power Technical Representative for
additional details.
Vo
MODULE
GND
Trim
Q1
Rtrim
Rmargin-up
Q2
Rmargin-down
Figure 46. Circuit Configuration for margining Output voltage
Monotonic Start-up and Shutdown
The 12V TLynxTM modules have monotonic start-up and shutdown
behavior for any combination of rated input voltage, output current
and operating temperature range.
Startup into Pre-biased Output
The 12V Pico TLynxTM 20A modules can start into a prebiased
output as long as the prebias voltage is 0.5V less than the set
output voltage. Note that prebias operation is not supported when
output voltage sequencing is used.
Output Voltage Sequencing
The 12V TLynxTM 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 VIN 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 VIN 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) is maintained 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. 47) 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 47. 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-SEQUENCETM 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-SEQUENCETM 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-
SEQUENCETM feature must be disabled. For additional
guidelines on using the EZ-SEQUENCETM 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.
Power Good
The 12V TLynxTM modules provide a Power Good (PGOOD)
signal that is implemented with an open-drain output to
indicate that the output voltage is within the regulation limits
of the power module. The PGOOD signal will be de-asserted
to a low state if any condition such as overtemperature,
overcurrent or loss of regulation occurs that would result in
the output voltage going ±11% outside the setpoint value.