CPFE1000FI SERIES
POWER SUPPLY
OPERATION MANUAL
9
19 August 2020
11. Parallel Operation (PS terminal)
By connecting the PS terminal of each CPFE1000FIxx, output current can be equally drawn from each unit. A maximum
of 6 units of the same model can be connected.
Maximum output current is derated by parallel operation units as shown in Table 11-1.
Note that usage of power module at out-of-rated condition might result in power module temperature abnormal rise or
damage.
Parallel units
Maximum output current
～
3 units
90% of nominal output current
4
～
6 units
85% of nominal output current
Table 11-1 Condition for Parallel Operation
Set the accuracy of the output voltage /-1% when adjust the output voltage for parallel operation.
When adjusting the output voltage by applying external voltage at the TRIM terminal, insert approximately a 10k ohm
resistor between TRIM terminal and external source.
Moreover, external circuits are necessary for TRIM terminal at each individual module.
Fig. 11-1 Output Voltage Adjustment by applying external voltage
(For parallel operation)
Limitations of power supplies in parallel operation:
If the power supplies are not connected for redundant operation (no oring diodes), the green LED indicator on
all power supplies can be lit whenever the output common bus voltage is present and the output voltage read by
the I²C bus is the voltage of the output common bus; not of the individual power supply.
The output current reading by the I²C bus is the average value of all currents from the power supplies connected
in parallel.
Remote sense cannot compensate for the voltage drop across the oring diodes. To maximize the compensation
during redundant operation, attach the oring diodes as close as possible to the point of load and S to the
anode of the associated oring diode (See Fig. 11-3).
When recovering from a fault condition, the output recovery may be delayed for up to 20 seconds to allow for
proper start-up.
