Ericsson Internal
EBAOCMA
PRODUCT SPECIFICATION
3 (5)
Prepared (also subject responsible if other)
No.
3/1301-BMR 637 02
19
Technical Specification
Approved
Checked
Date
Rev
Reference
EN/LZT 146 306 R2C Jan 2007
PKM 4000D PINB series
DC/DC converters, Input 36-75 V, Output 40 A/132 W
MPM/BK [Andréas Svensson]
MICOSPE
2006-9-13
A
© Ericsson Power Modules AB
Operating information, cont.
Input And Output Impedance
Parallel Operation
The impedance of both the power source and the load will
interact with the impedance of the DC/DC converter. It is
most important to have a low characteristic impedance, both
at the input and output, as the converters have a low energy
storage capability. The PKM 4000DSeries DC/DC converters
have been designed to be completely stable without the need
The PKM 4000DSeries DC/DC converters can be paralleled
for redundancy if external o-ring diodes are used in series
with the outputs. It is not recommended to parallel the PKM
4000D Series DC/DC converters for increased power without
using external current sharing circuits.
for external capacitors on the input or the output circuits. The Over Temperature Protection (OTP)
performance in some applications can be enhanced by
The PKM 4000DSeries DC/DC converters are protected from
addition of external capacitance as described under
maximum capacitive load. If the distribution of the input
voltage source to the converter contains significant
inductance, the addition of a 100µF capacitor across the input
of the converter will help insure stability. This capacitor is not
required when powering the DC/DC converter from a low
impedance source with short, low inductance, input power
leads.
thermal overload by an internal over temperature shutdown
circuit. When the Pcb temperature (TC reference point)
exceeds the temperature trig point (120 °C) for the OTP circuit
the converter will cut down output power. The converter will
go into hiccup mode until safe operational temperature is
restored.
Maximum Capacitive Load
When powering loads with significant dynamic current
requirements, the voltage regulation at the load can be
improved by addition of decoupling capacitance at the load.
The most effective technique is to locate low ESR ceramic
capacitors as close to the load as possible, using several
capacitors to lower the effective ESR. These ceramic
capacitors will handle short duration high-frequency
components of dynamic load changes. In addition, higher
values of electrolytic capacitors should be used to handle the
mid-frequency components. It is equally important to use
good design practise when configuring the DC distribution
system.
Low resistance and low inductance Pcb layouts and cabling
should be used. Remember that when using remote sensing,
all resistance, inductance and capacitance of the distribution
system is within the feedback loop of the converter. This can
affect on the converters compensation and the resulting
stability and dynamic response performance. As a “rule of
thumb”, 100µF/A of output current can be used without any
additional analysis. For example with a 25A converter, values
of decoupling capacitance up to 2500 µF can be used without
regard to stability. With larger values of capacitance, the load
transient recovery time can exceed the specified value. As
much of the capacitance as possible should be outside the
remote sensing loop and close to the load. The absolute
maximum value of output capacitance is 10000 µF. For values
larger than this, please contact your local Ericsson Power
Modules representative.
Over Voltage Protection (OVP)
The PKM 4000DSeries DC/DC converters include output
overvoltage protection. In the event of an overvoltage
condition due to malfunction in the voltage monitoring
circuits, the converter's PWM will automatically dictate
minimum duty-cycle thus reducing the output voltage to a
minimum.
Over Current Protection (OCP)
The PKM 4000DSeries DC/DC converters include current
limiting circuitry that allows them to withstand continuous
overloads or short circuit conditions on the output. The output
voltage will decrease towards zero for output currents in
excess of max output current (Iomax).
The converter will resume normal operation after removal of
the overload. The load distribution system should be
designed to carry the maximum output short circuit current
specified.
ERICSSON [ ERICSSON ]
