FAN6208 Fairchild Semiconductor, FAN6208 Datasheet - Page 10

• Manufacturer Part Number: FAN6208
• Description: FAN6208 is a synchronous rectification (SR) controller for isolated LLC or LC resonant converters that can drive two individual SR MOSFETs emulating the behavior of rectifier diodes
• Manufacturer: Fairchild Semiconductor

© 2010 Fairchild Semiconductor Corporation
FAN6208 • Rev. 1.0.1
(c) When the DETL voltage has ringing around zero. As
RP Pin Function
The RP pin programs the level of green mode and t
Figure 16 shows how the mode is selected by the
voltage on the RP pin (open protection, short protection,
and HF/LF mode). When R
FAN6208 operates in low-frequency mode. Green mode
is enabled when t
is larger than 36KΩ, high-frequency mode is selected
and green mode is enabled for t
be also adjusted by a resistor on the RP pin. Figure 5
shows the relationship between t
different RP resistors.
depicted in Figure 8, the drain voltage of SR has
ringing around zero at light-load condition after the
switching transition of the primary-side switches.
When DETL voltage rises above 2V within 350ns
after DETL voltage drops to zero and stays above
2V longer than 150ns, the gate is shrunk by 1.2µs
(t
Figure 14. Gate Shrink by Feedback Detection
SHRINK-RNG
Figure 15. Gate Shrink by DETL Voltage
), as shown in Figure 15.
DETL
Ringing Around Zero
is smaller than 3.75µs. When R
RP
DETL
is less than 36KΩ,
DEAD
< 1.90µs. t
and t
DEAD
DETL
DEAD
can
for
RP
.
10
To handle abnormal conditions for IC pins, the RP pin
also provides open/short protection. When V
than V
protection is triggered. Figure 17 shows the RP pin short
protection timing sequence. If V
longer than t
shows the RP pin open protection timing sequence. If
V
is disabled.
RP
> V
RPS
RPO
Figure 17. RP Pin Short Protection
Figure 18. RP Pin Open Protection
(0.3V) or V
(3.65V) for longer than t
Figure 16.
RPOS
(2µs), FAN6208 is disabled. Figure 18
RP
is higher than V
RP Pin Operation
RP
RPOS
< V
RPO
(2µs), FAN6208
RPS
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(3.65V), the
(0.3V) for
RP
is less