GE Industrial Solutions Naos Raptor 40A - Manual (Page 14)

Data Sheet
July 11, 2011 Naos Raptor 40A Non Isolated Power Module:
5 – 13.8Vdc input; 0.6Vdc to 5.0Vdc Output; 40A output current
LINEAGE POWER 14
Feature Descriptions (continued)
Tunable Loop TM
The Naos Raptor 40A modules have a new feature
that optimizes transient response of the module called
Tunable Loop
TM . External capacitors are usually
added to improve output voltage transient response
due to load current changes. Sensitive loads may
also require additional output capacitance to reduce
output ripple and noise. 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.
To use the additional external capacitors in an optimal
manner, the Tunable Loop
TM feature allows the loop
to be tuned externally by connecting a series R-C
between the SENSE and TRIM pins of the module, as
shown in Fig. 44. This R-C allows the user to
externally adjust the voltage loop feedback
compensation of the module to match the filter
network connected to the output of the module.
Recommended values of R
TUNE
and C
TUNE
are given
in Tables 2 and 3. Table 2 lists recommended values
of R
TUNE
and C
TUNE
in order to meet 2% output
voltage deviation limits for some common output
voltages in the presence of a 20A to 40A step change
(50% of full load), with an input voltage of 12V. Table
3 shows the recommended values of R
TUNE
and C
TUNE
for different values of ceramic output capacitors up to
1500uF, again for an input voltage of 12V. The value
of R
TUNE
should never be lower than the values shown
in Tables 2 and 3. Please contact your Lineage Power
technical representative to obtain more details of this
feature as well as for guidelines on how to select the
right value of external R-C to tune the module for best
transient performance and stable operation for other
output capacitance values.
SENSE+
MODULE
TRIM+
VOUT
RTune
TRIM-
CTune
RTrim
Figure. 44. Circuit diagram showing connection of
R
TUME
and C
TUNE
to tune the control loop of the
module.
Table 2. Recommended values of R
TUNE
and C
TUNE
to obtain transient deviation of 2% of Vout for a
20A step load with Vin=12V.
Vout 5V 3.3V 2.5V 1.8V 1.2V 0.69V
Cext
6x47 μF
+
330 μF
Polymer
2x47 μF
+
3x330 μF
Polymer
4x47 μF
+
4x330 μF
Polymer
3x47 μF
+
6x330 μF
Polymer
2x47 μF
+
10x330 μF
Polymer
2x47 μF
+
22x330 μF
Polymer
R
TUNE
75 62 62 39 39 30
C
TUNE
10nF 18nF 27nF 47nF 68nF 180nF
ΔV 100mV 64mV 50mV 36mV 24mV 12mV
Table 3. General recommended values of of R
TUNE
and C
TUNE
for Vin=12V and various external
ceramic capacitor combinations.
Cext 2x47 μF 4x47μF 10x47μF 20x47μF 30x47μF
R
TUNE
75 75 39 33 30
C
TUNE
3300pF 4700pF 8.2nF 12nF 18nF