EQ2660-9R Datasheet, PDF (7/26 Pages) Power-One – Q Series Data Sheet 66 – 132 Watt DC-DC Converters

Q Series Data Sheet
®
66 – 132 Watt DC-DC Converters
Input Fuse
An incorporated fuse in series to the negative input line
protects against severe defects. The fuse is not externally
accessible. Reverse polarity at the input will cause the fuse to
blow.
Note: Customer-specific models with no internal fuse are
available on request; the customer must prevew an external fuse
according to table 3.
Table 3: Fuse specifications
Model
BQ
GQ
CQ
48Q
Fuse type
very fast acting
very fast acting
very fast acting
very fast acting
Reference and rating
2× Littelfuse 251, 10 A, 125 V
2× Littelfuse 251, 7 A, 125 V
Littelfuse 251, 10 A, 125 V
Littelfuse 251, 10 A, 125 V
DQ
very fast acting Littelfuse 251, 7 A, 125 V
EQ
very fast acting Littelfuse 263, 5 A, 250 V
Input Transient Protection
A metal oxide VDR (Voltage Dependent Resistor) together with
the input fuse and a symmetrical input filter form an effective
protection against high input transient voltages, which typically
occur in most installations, especially in battery-driven mobile
applications.
Nominal battery voltages in use are: 24, 36, 48, 60, 72, 96, and
110 V. In most cases each nominal value is specified in a
tolerance band of –30% to +25%, with short excursions to
±40% or even more.
In some applications, surges according to RIA 12 are specified
in addition to those defined in IEC 60571-1 or EN 50155. The
power supply must not switch off during these surges and
since their energy can practically not be absorbed, an
extremely wide input voltage range is required. The Q Series
input range has been designed and tested to meet most of
these requirements. See also Electromagnetic Immunity.
Input Under-/Overvoltage Lockout
If the input voltage falls outside the limits of V_{i 100 ms}, an
internally generated inhibit signal disables the output(s).
Inrush Current
The inherent inrush current value is lower than specified in the
standard ETS 300132-2. The converters operate with
relatively small input capacitance, resulting in low inrush
current of short duration. As a result, in a power-bus system
the converters can be hot-swapped, causing negligible
disturbance.
Input Stability with Long Supply Lines
If a Q Series converter is connected to the power source with
long input lines which exhibit a considerable inductance, an
additional external capacitor connected in parallel to the input
improves stability and avoids oscillations.
Actually, a Q Series converter with nominal load acts like a
negative resistor, as the input current rises when the input
voltage decreases. It tends to oscillate with a resonant
frequency determined by the line inductance L_{ex t} and the input
capacitance C_i + C_ext and damped by the resistors R_i + R_ext.
The whole system is not linear at all and eludes a simple
calculation. One basic condition is given by the formula:
R_ext
<<
—^V—ⁱⁿ—² •
P_o
η
R_ext is the series resistor of the source voltage including input
lines. If this condition is not fulfilled, the converter cannot reach
stable operating conditions. Worst case conditions are low
input voltage V_i and high output power P_o.
Low inductance L_ext of the input lines and a parallel connected
input capacitor C_ext are helpful. Recommended values for C_ext
are given in table 4, which should allow stable operation up to
an input inductance of 2 mH.
L_ext
R_ext
Vi+
+
C_ext
Vi–
JM001
Converter
Vo+
C_i
R_i
Vo–
Fig. 8
Input configuration
Table 4: C_i and recommended values for C_ext
Model
BQ
C_i
220 µF
Recomm. C_ext
≥ 680 µF
GQ
110 µF
≥ 470 µF
CQ
50 µF
≥ 470 µF
48Q
50 µF
≥ 470 µF
DQ
22 µF
≥150 µF
EQ
11 µF
≥ 68 µF
Voltage
40 V
63 V
100 V
100 V
125 V
200 V
BCD20011- G Rev AG, 12-Mar-2012
Page 7 of 26
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