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The trim-down resistor (Rt_down) values for the trim-down voltage range from -5% to -20% can be found in Tables 6-2.
The trim down connection diagram is shown in Figure 6-4.
% Trim-Down
of Vo_nom
(Vo)
- 5%
- 10%
- 15%
- 20%
10000
1000
100
10
0
% Decrease in Output Voltage,
Fig. 6-3 Trim-Down Resistance vs. Percentage Voltage Trim-
Down.
6.3
Inrush Current
Input inrush or surge current changes with thermal fuse resistor (R2) value and the external boost converter bulk
capacitance value (C9 and C10). It is recommended that actual evaluation testing be performed to confirm the inrush
current value.
The inrush current peak values shown in the specification or data sheet are measured at nominal lines (115Vac and
230Vac), at 25 ºC using the basic connection as shown in Figure 5-1.
The external line fuse should be chosen to handle the measured inrush peak current and based on the PFH product label. If
used in conjunction with the line fuse, circuit breakers should be selected using the same criteria.
REV 2.8 (March 30, 2020)
PFH500F – 12 – xxx
Trim-Down
Calculated Vout
Resistance
(Ω)
92.0k
40.9k
23.9k
15.3k
2
4
6
8
10
12
14
Table 6-2 External Trim-Down Resistor Value
PFH500F – 28 – xxx
Calculated Vout
(V)
11.4V
26.6V
10.8V
25.2V
10.2V
23.8V
9.6V
22.4V
16
18
20
(%)
Fig. 6-4 External Trim-Down Circuit Connection.
INSTRUCTION MANUAL
PFH500F – 48 – xxx
Calculated Vout
(V)
(V)
45.6V
43.2V
40.8V
38.4V
TDK-Lambda
PFH500-SERIES
17
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