GPP5V0-20 Datasheet, PDF (7/8 Pages) Galaxy Power, Inc. – Polaris Series

Application Notes
For the GPP5V0-15 and GPP5V0-20, the trim resistor,
R_trim for these two units is:
R_TRIM = ——⁶⁰—^.5—⁰ —^{– 5}—^.9—¹ —^{* V}—^o— Kohms
V_O – 5
Thermal Considerations:
Thermal considerations are an important factor in the
reliable operation of the converter. The maximum
operating baseplate temperature is 100°C. The
maximum recommended operating baseplate
temperature is 90°C. The baseplate temperature is a
function of the losses within the converter, the converter
ambient temperature, and airflow across the heat sink.
The reference baseplate temperature is measured at the
center coordinates of the baseplate.
The baseplate temperature can be approximated by the
following equation:
T_BASEPLATE
=
P_OUTPUT
*
1- η
—_η—
*
R_{BASEPLATE-AMBIENT}
+
T_AMBIENT
Where:
T_BASEPLATE
T_ambient
η
is the temperature of the
baseplate.
is the local ambient temperature
around the converter
is the efficiency of the converter
(see Table on page 5)
R_{baseplate-ambient}
is the thermal resistance from the
baseplate to the ambient
environment. This is a function
of the heat sink and air velocity.
Thermal Shutdown: The converter shall shutdown
under a thermal overload. This is a latched condition
and either the input voltage has to be recycled or the
primary enable signal (P_ENABLE_L) has to be
recycled to reset normal operation.
Overcurrent Protection: The converter shall survive
any overload condition indefinitely including short
circuit. The values of current limit and short circuit
shall be per the Output Characteristics Table.
Overvoltage Protection: The converter shall be
protected against any overvoltage across Vout pins by
shutting down the output at the values specified in the
Output Characterisitics Table. This is a latched
condition and either the input voltage has to be recycled
or the primary enable signal (P_ENABLE_L) has to be
recycled to reset normal operation.
Recommended Input Filter, Fuse and Case
Connections: A fuse is required in series with the plus
or minus side of the 48V input to meet safety
requirements. The following input filter circuit is
recommended for all applications. The fuse should be
inserted between the capacitors and the plus or minus
input of the converter. The case should be connected to
the output return.
2 ^L1 1
48V
°
+
C1
270µF
63V
C2
1µF
100V
48V RTN
In (+)
In (–)
C3
1µF
100V
4 ₈₀
°
3
UH
F1
C4
1µF
100V
+
Input
–
DC/DC
Converter
P Enable
+
Output
Case
–
In (+)
In (–)
R_LOAD
L1
Common Mode Inductor
C1
270µF, 63V Aluminum Electrolytic Capacitor
C2-C4 1µF, 100V Ceramic capacitor
Polaris Series, Page 7
WWW.GALAXYPWR.COM
Part No. 99–003 Rev. 1.0