GE Industrial Solutions Naos Raptor 20A - Manual (Page 15)

Data Sheet
July 11, 2011 Naos Raptor 20A: Non Isolated Power Module:
4.5 – 14Vdc input; 0.59Vdc to 6Vdc Output; 20A output current
LINEAGE POWER 15
MODULE
Trim+
Vo
Trim-
Q1
Rtrim
Rmargin-up
Q2
Rmargin-down
Figure 50. Circuit Configuration for margining Output
voltage.
Monotonic Start-up and Shutdown
The Naos Raptor 20A modules have monotonic start-up
and shutdown behavior for any combination of rated input
voltage, output current and operating temperature range.
Tunable Loop TM
The Naos Raptor 20A 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.
51. 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 3 and 4. Table 3 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 5A to 10A step change (50% of full load),
with an input voltage of 12V. Table 4 shows the
recommended values of R
TUNE
and C
TUNE
for different
values of ceramic output capacitors up to 1000uF, again
for an input voltage of 12V. The value of R
TUNE
should
never be lower than the values shown in Tables 3 and 4.
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. 51. Circuit diagram showing connection of
R
TUME
and C
TUNE
to tune the control loop of the
module.
Table 3. Recommended values of R
TUNE
and C
TUNE
to
obtain transient deviation of 2% of Vout for a 10A
step load with Vin=12V.
Vout 5V 3.3V 2.5V 1.8V 1.2V 0.69V
Cext
330 μF
Polymer
4x47 μF
+
330 μF
Polymer
2x47 μF
+
2x330 μF
Polymer
6x47 μF
+
3x330 μF
Polymer
7x330 μF
Polymer
23x330 μF
Polymer
R
TUNE 75 51 51 51 51 31
C
TUNE
100nF 150nF 220nF 330nF 330nF 330nF
ΔV 94mV 66mV 50mV 36mV 24mV 12mV
Table 4. General recommended values of of R
TUNE
and
C
TUNE
for Vin=12V and various external ceramic
capacitor combinations.
Cext 2x47 μF 4x47μF 6x47μF 10x47μF 20x47μF 30x47μF
R
TUNE
75 75 75 51 51 51
C
TUNE
15nF 27nF 33nF 47nF 68nF 82nF