Ericsson Internal
E
EAB/FJB/GMF Oscar Persson
PRODUCT SPECIFICATION
2 (5)
Prepared (also subject responsible if other)
No.
3/1301-BMR 662 00+ Uen
14
Technical Specification
Approved
Checked
Date
Rev
Reference
EN/LZT 146 420 R2A May 2010
PKB 4000A series Direct Converters
Input 38-72 V, Output up to 30 A / 125 W
EAB/FJB/GMF [Natalie Johansson]
MICJAKE
2010-04-11
B
© Ericsson AB
capacitors connected to the input or output. The performance
in some applications can be enhanced by addition of external
capacitance as described under External Decoupling
Capacitors.
Operating information
Input Voltage
The input voltage range 38 to 72Vdc meets the requirements
of the European Telecom Standard ETS 300 132-2 for normal
input voltage range in –48 and –60 Vdc systems, -40.5 to -
57.0 V and –50.0 to -72 V respectively.
At input voltages exceeding 72 V, the power loss will be higher
than at normal input voltage and TP1 must be limited to
absolute max +125°C. The absolute maximum continuous
input voltage is 80 Vdc.
If the input voltage source contains significant inductance, the
addition of a 100 µF capacitor across the input of the product
will ensure stable operation. The capacitor is not required
when powering the product from an input source with an
inductance below 10 µH. The minimum required capacitance
value depends on the output power and the input voltage. The
higher output power the higher input capacitance is needed.
External Decoupling Capacitors
Turn-off Input Voltage
When powering loads with significant dynamic current
requirements, the voltage regulation at the point of load can
be improved by addition decupling capacitors at the load with
>10% of the maximum recommended value found in the
electrical specification.
The products monitor the input voltage and will turn on and
turn off at predetermined levels.
The minimum hysteresis between turn on and turn off input
voltage is 2V.
The most effective technique is to locate low ESR ceramic and
electrolytic capacitors as close to the load as possible, using
several parallel capacitors to lower the effective ESR. The
ceramic capacitors will handle high-frequency dynamic load
changes while the electrolytic capacitors are used to handle
low frequency dynamic load changes. It is equally important to
use low resistance and low inductance PCB layouts and
cabling.
Remote Control (RC)
The products are fitted with a
remote control function referenced
to the primary negative input
connection (-In), with negative and
positive logic options available. The
RC function allows the product to
be turned on/off by an external
device like a semiconductor or
mechanical switch. The RC pin has
an internal pull up resistor to +In.
External decoupling capacitors will become part of the
product’s control loop. The control loop is optimized for a wide
range of external capacitance and the maximum
recommended value that could be used without any additional
analysis is found in the Electrical specification.
The ESR of the capacitors is a very important parameter.
Stable operation is guaranteed with a verified ESR value of
>10 mΩ across the output connections.
The maximum required sink current is 1 mA. When the RC pin
is left open, the voltage generated on the RC pin is
5 – 7 V or 10-13V for “P” option. The standard product is
provided with “negative logic” remote control and will be off
until the RC pin is connected to the -In. To turn on the product
the voltage between RC pin and -In should be less than 1V.
To turn off the converter the RC pin should be left open, or
connected to a voltage higher than 4.5 V referenced to -In. In
situations where it is desired to have the product to power up
automatically without the need for control signals or a switch,
the RC pin can be wired directly to -In.
For further information please contact your local Ericsson
Power Modules representative.
Output Voltage Adjust (Vadj
)
The products have an Output Voltage Adjust pin (Vadj). This
pin can be used to adjust the output voltage above or below
Output voltage initial setting.
When increasing the output voltage, the voltage at the output
pins (including any remote sense compensation ) must be
kept below the threshold of the over voltage protection, (OVP)
to prevent the product from shutting down. At increased output
voltages the maximum power rating of the product remains the
same, and the max output current must be decreased
correspondingly.
To increase the voltage the resistor should be connected
between the Vadj pin and +Sense pin. The resistor value of the
Output voltage adjust function is according to information
given under the Output section for the respective product.
To decrease the output voltage, the resistor should be
connected between the Vadj pin and –Sense pin.
The second option is “positive logic” remote control, which can
be ordered by adding the suffix “P” to the end of the part
number. When the RC pin is left open, the product starts up
automatically when the input voltage is applied. Turn off is
achieved by connecting the RC pin to the -In. To ensure safe
turn off the voltage difference between RC pin and the -In pin
shall be less than 1V. The product will restart automatically
when this connection is opened.
See Design Note 021 for detailed information.
Input and Output Impedance
The impedance of both the input source and the load will
interact with the impedance of the product. It is important that
the input source has low characteristic impedance. The
products are designed for stable operation without external
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