FSFR2100 Fairchild Semiconductor, FSFR2100 Datasheet - Page 10

• Manufacturer Part Number: FSFR2100
• Description: IC SWIT PROG OVP OCP 9SIP
• Manufacturer: Fairchild Semiconductor
• Series: FPS™r

Specifications of FSFR2100

• Output Isolation: Isolated
• Frequency Range: 94kHz ~ 106kHz
• Voltage - Input: 9.6 V ~ 25 V
• Voltage - Output: 500V
• Power (watts): 400W
• Operating Temperature: -40°C ~ 130°C
• Package / Case: 9-SIP
• Output Voltage: 24 V
• Output Current: 8.3 A
• Output Power: 450 W
• Switching Frequency: 300 KHz
• Operating Temperature Range: - 40 C to + 130 C
• Mounting Style: Through Hole
• Duty Cycle (max): 52 %
• Isolated/non-isolated: Isolated
• For Use With: FEB212 - BOARD EVAL FOR FSFR2100
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

© 2007 Fairchild Semiconductor Corporation
FSFR2100 • Rev.1.0.8
in Figure 19. FSFR2100 also has an internal soft-start for
3ms to reduce the current overshoot during the initial
cycles, which adds 40kHz to the initial frequency of the
external soft-start circuit, as shown in Figure 20. The
initial frequency of the soft-start is given as:
It is typical to set the initial frequency of soft-start two ~
three times the resonant frequency (f
network.
The soft-start time is three to four times of the RC time
constant. The RC time constant is as follows:
4. Control Pin
The FSFR2100 has a control pin for protection, cycle
skipping, and remote on/off. Figure 21 shows the internal
block diagram for control pin.
Protection: When the control pin voltage exceeds 5V,
protection
described in the protection section.
Pulse Skipping: FSFR2100 stops switching when the
control pin voltage drops below 0.4V and resumes
switching when the control pin voltage rises above 0.6V.
To use pulse-skipping, the control pin should be
connected to the opto-coupler collector pin. The
frequency that causes pulse skipping is given as:
T
f
SS
ISS
f
=
ISS
Figure 20. Frequency Sweeping of Soft-start
=
R
(
f
SS
s
Figure 21. Internal Block of Control Pin
5.2
R
⋅
C
min
k
is
SS
Ω
+
40kHz
triggered.
5.2
R
SS
k
Ω
) 100 40 (
×
Detailed
+
Control loop
kHz
take over
O
applications
) of the resonant
)
time
are
(3)
(4)
10
Remote On / Off: When an auxiliary power supply is
used for standby, the main power stage using FSFR2100
can be shut down by pulling down the control pin voltage,
as shown in Figure 23. R1 and C1 are used to ensure
soft-start when switching resumes.
SKIP
Figure 22. Control Pin Configuration for Pulse
=
Figure 23. Remote On / Off Circuit
5
R
2 .
min
k
+
. 4
R
16
max
Skipping
k
x
100
(
kHz
)
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