FAN6210MY Fairchild Semiconductor, FAN6210MY Datasheet - Page 7

• Manufacturer Part Number: FAN6210MY
• Description: TAPE REEL \ Synchronous Rectifier Trigger For Dual Forward
• Manufacturer: Fairchild Semiconductor
• Series: -r

Specifications of FAN6210MY

• Applications: Power Supplies
• Voltage - Input: 10.5 V ~ 24.5 V
• Voltage - Supply: 7 V ~ 24 V
• Current - Supply: -
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

© 2009 Fairchild Semiconductor Corporation
FAN6210 Rev. 1.0.2
Function Description
Figure 13 and Figure 14 show the simplified circuit
diagram
waveforms. Switches Q
together. Once Q
is applied across the transformer primary side and
power is delivered to the secondary side through the
transformer, powering diode D
magnetizing current linearly increases. When Q
are turned off, the magnetizing current of the
transformer forces the reset diodes (D
negative input voltage is applied across the transformer
primary side. During this time, magnetizing current
linearly decreases to zero and the secondary-side
inductor current freewheels through diode D
synchronous rectifiers SR
diodes D
between drive signals for SR
V
IN
Figure 14. Key Waveforms of Dual-Forward
Q
Figure 13. Simplified Circuit Diagram of
1
1
V
+
-
D
of
and D
D
dual-forward
R1
Q
2
2
Dual-Forward Converter
1
, it is important to have proper timing
and Q
V
D
+
-
x
R2
I
1
m
Converter
L
and Q
2
1
m
and SR
are turned on, input voltage
1
converter
and SR
D
1
2
. During this time, the
1
are turned on and off
2
SR
are used instead of
SR
2
2
.
1
R1
D
and
and D
2
L
I
Lo
o
2
1
its
. When
V
R2
and Q
o
) and
key
2
7
Figure 15 shows the typical application circuit of
FAN6210. SIN is the gate drive output of the PWM
controller. SOUT is obtained from SIN by adding a
delay, which is used to drive two switches Q
The value of the DET resistor is recommended as 10kΩ
and D
breakdown voltage of Zener diode D
to protect the DET pin from over voltage.
Figure 16 shows the timing diagrams for heavy-load
and light-load conditions.
The
MOSFETs is determined by the SN and SP signals.
FAN6206 turns on SR MOSFETs at the rising edge of
the XP signal, while it turns off SR MOSFETs at the
rising edge of XN. Within one switching cycle, XP and
XN are obtained two times, respectively.
The XN signal has a 300ns pulse-width and is triggered
by the rising edge and falling edge of the SIN signal
after a short time delay (t
XP signal has a 700ns pulse-width and is triggered by
the rising edge of the SOUT signal after an adjustable
time delay (t
signal. The relation between the delay resistor (R
and the delay time is shown in Figure 17. The triggering
of the XP signal by DET is prohibited while the XN
signal is HIGH. Therefore, the XP signal is not triggered
at the falling edge of the DET signal and is delayed until
the XN signal drops to zero at heavy-load condition. At
light-load condition, the DET falling edge comes after
the XN signal drops to zero and the XP signal is
triggered at the falling edge of the DET signal after a
short time delay (t
From PWM
controller
B
switching
V
1
2
3
4
IN
Figure 15. Typical Application Circuit
is used to block high voltage on winding. The
XP
XN
SIN
RDLY
+
-
FAN6210
DLY_XP
SOUT
GND
VDD
DET
PD_DET
operation
) and by the falling edge of the DET
8
7
6
5
).
Drv
Drv
PD_XN
D
z
of
).
Q
D
B
1
the
Z
Q
is typically 5~6V
2
secondary
SN of FAN6206
SP of FAN6206
www.fairchildsemi.com
1
and Q
DELAY
2
.
SR
)