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5.13 RL Inrush Relay (12V Coil, 10A/277Vac; 16A/125Vac)
An inrush relay is connected in parallel with R2 resistor. As soon as VBUS reaches the pre-set value (close to the peak of
the maximum ac line voltage), the inrush control pin will energize the relay. This method mitigates or even eliminates the
second inrush current event during the relay closing. It is very important to make sure that the relay contacts are
opened before applying AC power. Otherwise, an inrush current surge will damage the PFH Series module.
The inrush relay chosen must have a maximum switching voltage ≥ 265Vac. A relay with minimum of 10A / 277Vac,
16A / 125Vac rating, and 12V / (15mA to 20mA) nominal coil operating voltage and current is recommended.
Note:
(1) Panasonic relay (JVN1A-12V-F) was used during the testing process.
6
Explanation of Functions and Precautions
6.1
Input Voltage Range
Input AC voltage source should be within the ranged from 85 - 265Vrms (47-63Hz). Connecting the PFH Series
module to any power source outside of this specified range will prevent the module from starting.
PFH500 series power module is certified by various safety agencies with a certified label indicating: 100-240Vac, 50-
60Hz, 8A.
6.2
Output Voltage Adjustment Range
The output voltage of the PFH Series module can be adjusted up and down by connecting a trim resistor between Trim pin
and RS(+) pin or Vout(-) pin. Care must be taken to prevent the trim up voltage from exceeding 20% of the nominal voltage.
Otherwise, it may activate the module's OVP protection function.
Output Voltage Adjustment Range: ±20% of the nominal output voltage setting
When trimming up the output voltage, the output current needs to be reduced to keep the maximum output power to 504W
or less. Operating beyond the specified ratings can cause permanent damage to the power module.
The trim-up and the trim-down connections using external resistor are shown in Fig. 6-2, and Figure 6-4. If the remote
sensing feature is NOT used, the RS(+) pin needs to be connected to Vout(+) for local sensing. For details on Remote
Sensing function, refer to Sec 6.8, Remote Sensing.
NOTE: Due to noisy environments, it is strongly recommended that an external 0.1µF capacitor (Min) be placed from the
Trim pin to SGND.
Output Voltage Adjustment using external Fixed Trim Resistor
Trim Up: With a trim resistor connected between the Trim pin and Vout (+) pin, the output voltage is adjusted up. To adjust
the output voltage up a percentage of Vout (%) from Vo,nom, the trim resistor (in k) should be chosen according to the
following equation:
%
= 100(Vo,nom - Vdesired) / Vo_nom
Vref = 1.22V
REV 2.8 (March 30, 2020)
V
, 0
nom
R
. 5
11
(
trim
_
up
Vref
(
100
%)
100
) 2
%
%
TDK-Lambda
PFH500-SERIES
INSTRUCTION MANUAL
(Formula 5-4)
15
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