GE Industrial Solutions 12V PicoTLynx 6A - Manual (Page 16)

GE
Data Sheet
12V PicoTLynx TM 6A: Non-Isolated DC-DC Power Modules
4.5Vdc –14Vdc input; 0.59Vdc to 5.5Vdc output; 6A Output Current
May 2, 2013 ©2013 General Electric Company. All rights reserved. Page 16
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-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 GE technical
representative for additional information.
Power Good
The 12V Pico TLynx TM 6A 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 ±10% outside the setpoint value. The PGOOD
terminal should be connected through a pullup resistor
(suggested value 100K
Ω) to a source of 5VDC or lower.
Tunable Loop TM
The 12V Pico TLynx TM 6A modules have a new feature that
optimizes transient response of the module called Tunable
Loop
TM .
External capacitors are usually added to the output of
the module for two reasons: to reduce output ripple and
noise (see Fig. 41) and to reduce output voltage
deviations from the steady-state value in the presence of
dynamic load current changes. Adding external
capacitance however affects the voltage control loop of
the module, typically causing the loop to slow down with
sluggish response. Larger values of external capacitance
could also cause the module to become unstable.
The Tunable Loop TM allows the user to externally adjust
the voltage control loop to match the filter network
connected to the output of the module. The Tunable
Loop
TM is implemented by connecting a series R-C
between the SENSE and TRIM pins of the module, as
shown in Fig. 48. This R-C allows the user to externally
adjust the voltage loop feedback compensation of the
module.
MODULE
VOUT
SENSE
TRIM
GND
RTUNE
CTUNE
RTrim
C O
Figure. 48. Circuit diagram showing connection of
R
TUME
and C
TUNE
to tune the control loop of the module.