GE Industrial Solutions NH050x-L Series - Manual (Page 12)

NH033x-L and NH050x-L Series Power Modules: Data Sheet
5 Vdc Input; 1.2 Vdc to 3.3 Vdc Output; 10 A and 15 A March 2010
12 12 Lineage Power
Design Considerations
(continued)
Input Source Impedance (continued)
To further reduce the input reflected ripple current, a
filter inductor (L
FILTER
) can be connected between the
supply and the external input capacitors (see Figure
37). The filter inductor should be rated to handle the
maximum power module input current of 10 Adc for the
NH033x-L and 16 Adc for the NH050x-L.
If the amount of input reflected-ripple current is unac-
ceptable with an external L-C filter, more capacitance
may be added across the input supply to form a C-L-C
filter. For best results, the filter components should be
mounted close to the power module.
8-1216(C).a
Figure 37. Setup with External Input Filter to
Reduce Input Reflected-Ripple Current
and Ensure Stability
Output Capacitance
The NH033x-L and NH050x-L Series Power Modules
can be operated with large values of output capaci-
tance. In order to maintain stability, choose a capacitor
bank so that the product of their capacitance and ESR
is greater than 50 x 10
–6 (e.g., 1,000 µF x 0.05 Ω =
50 x 10 –6 ). For complex or very low ESR filters, consult
the Technical Support for stability analysis.
Safety Considerations
For safety-agency approval of the system in which the
power module is used, the power module must be
installed in compliance with the spacing and separation
requirements of the end-use safety agency standard,
i.e., UL 60950, CSA C22.2 No. 60950-00, and VDE
0805 (IEC60950).
For the converter output to be considered meeting the
requirements of safety extra-low voltage (SELV), the
input must meet SELV requirements.
The power module has extra-low voltage (ELV) outputs
when all inputs are ELV.
The input to these units is to be provided with a maxi-
mum 20 A normal-blow fuse in the ungrounded lead.
Feature Descriptions
Overcurrent Protection
To provide protection in a fault condition, the unit is
equipped with internal overcurrent protection. The unit
operates normally once the fault condition is removed.
Under some extreme overcurrent conditions, the unit
may latch off. Once the fault is removed, the unit can
be reset by toggling the remote on/off signal for one
second or by cycling the input power.
Remote On/Off
To turn the power module on and off, the user must
supply a switch to control the voltage at the ON/OFF
pin (V
on/off
). The switch should be an open collector pnp
transistor connected between the ON/OFF pin and the
V
I
pin or its equivalent (see Figure 38).
During a logic low when the ON/OFF pin is open, the
power module is on and the maximum V
on/off
generated
by the power module is 0.3 V. The maximum allowable
leakage current of the switch when V
on/off
= 0.3 V and
V
I
= 5.5 V (V
switch
= 5.2 V) is 50 µA.
During a logic high, when V
on/off
= 2.8 V to 5.5 V, the
power module is off and the maximum I
on/off
is 10 mA.
The switch should maintain a logic high while sourcing
10 mA.
Leave the remote ON/OFF pin open if not using that
feature.
The module has internal capacitance to reduce noise
at the ON/OFF pin. Additional capacitance is not gen-
erally needed and may degrade the start-up character-
istics of the module.
TO OSCILLOSCOPE
C 1
V I
GND
SUPPLY
CURRENT
PROBE
L SOURCE
470 µF
L FILTER
+
C 2