GE Industrial Solutions PicoTLynx 3A - Manual (Page 14)

GE
Data Sheet
PicoTLynx TM 3A: Non-Isolated DC-DC Power Modules
2.4Vdc –5.5Vdc input; 0.6Vdc to 3.63Vdc output; 3A Output Current
September 11, 2013 ©2013 General Electric Company. All rights reserved. Page 14
1.2 2.0
1.5 1.333
1.8 1.0
2.5 0.632
3.3 0.444
By using a ±0.5% tolerance trim resistor with a TC of
±25ppm, a set point tolerance of ±1.5% can be achieved as
specified in the electrical specification. The POL
Programming Tool available at
www.lineagepower.com
under the Design Tools section, helps determine the required
trim resistor needed for a specific output voltage.
V
O
+
TRIM
GND
R
trim
LOAD
V
IN
+
ON/OFF
SENSE
Fi
gure 41. Circuit configuration for programming output
voltage using an external resistor.
Remote Sense
The Pico TLynx TM 3A modules have a Remote Sense feature
to minimize the effects of distribution losses by regulating
the voltage at the SENSE pin. The voltage between the
SENSE pin and VOUT pin must not exceed 0.5V. Note that the
output voltage of the module cannot exceed the specified
maximum value. This includes the voltage drop between the
SENSE and Vout pins. When the Remote Sense feature is not
being used, connect the SENSE pin to the VOUT pin.
Voltage Margining
Output voltage margining can be implemented in the Pico
TLynx TM 3A modules by connecting a resistor, R
margin-up
, from
the Trim pin to the ground pin for margining-up the output
voltage and by connecting a resistor, R
margin-down
, from the
Trim pin to output pin for margining-down. Figure 42 shows
the circuit configuration for output voltage margining. The
POL Programming Tool, available at www.lineagepower.com
under the Design Tools section, also calculates the values of
R
margin-up
and R
margin-down
for a specific output voltage and %
margin. Please consult your local GE technical
representative for additional details.
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 Pico TLynx TM 3A 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 5.5V Pico TLynx TM 6A 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 Pico TLynx TM 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 the SEQ pins of multiple modules
together, all 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