Datasheet
6/16
Technical Note
Block diagram / Application circuit / Pin assignment
(BD9001F)
Fig.26Fig.25
No.
1
2
3
4
5
6
7
FIN
Pin name
V
IN
SW
RT
GND
FB
INV
EN/SYNC
-
Fig.23
No.
1
2
3
4
5
6
7
8
Function
Power supply input
Output
Error Amp output
Output voltage feedback
Enable
Frequency setting resistor connection
Ground
Power system power supply input
Pin name
V
IN
SW
FB
INV
EN
RT
GND
PV
IN
Fig.24
No.
1
2
3
4
5
6
7
FIN
Pin name
V
IN
SW
FB
GND
INV
RT
EN
-
(BD9778F)
(BD9781HFP)
(BD9778HFP)
3
Vref
220µF 1µF
33µH
330µF
390kΩ
0.1µF
4700pF
10kΩ
23kΩ
1
8
-
+
+
-
+
4
SOFT
START
OSC
DRIVER
LATCH
TSD
-
+
6
2
ON/OFF
5
7
EN
L:OFF
H:ON
V
IN
PVIN
INV
ERROR AMP
RESET
SW
V
O
GND
CURRENT LIMIT
Vref
FB RT
PWM
COMPARATOR
V
IN
INVSW
FBVIN
GND
RT
EN
PVIN
EN
RT
INV
GND
FB
SW
V
IN
EN/SINC
INV
FB
GND
RT
SW
VIN
150kΩ
3
Vref
1
-
+
+
-
+
5
SOFT
START
OSC
DRIVER
LATCH
TSD
-
+
6
2
ON/OFF
7
4
EN
L:OFF
H:ON
V
IN
INV
ERROR AMP
RESET
SW
V
O
GND
CURRENT LIMIT
Vref
FB RT
PWM
COMPARATOR
V
IN
220µF 1µF
33µH
330µF
390kΩ
0.1µF
4700pF
10kΩ
23kΩ
150kΩ
5
Vref
1
-
+
+
-
+
6
SOFT
START
OSC
DRIVER
LATCH
TSD
-
+
3
2
SYNC
ON/OFF
7
4
EN/
SYNC
L:OFF
H:ON
V
IN
INV
ERROR AMP
RESET
SW
V
IN
VO
GND
CURRENT LIMIT
Vref
FB RT
PWM
COMPARATOR
220µF 1µF
33µH
330µF
390kΩ
0.1µF
4700pF
10kΩ
23kΩ
150kΩ
Function
Power supply input
Output
Error Amp output
Ground
Output voltage feedback
Frequency setting resistor connection
Enable
Ground
Function
Power supply input
Output
Frequency setting resistor connection
Ground
Error Amp output
Output voltage feedback
Enable/Synchronizing pulse input
Ground
3
Vref
SOFT
START
8
-
+
+
-
+
4
OSC
DRIVER
LATCH
TSD
-
+
6
1
7
INV
ERROR AMP
RESET
SW
V
O
VIN
GND
CURRENT LIMIT
Vref
V
IN
FB
RT
PWM
COMPARATOR
INVN.C.
FBSW
GND
RT
EN
VIN
220µF 1µF
33 µH
330µF
390kʎ
0.1µF
4700pF
10kʎ
23kʎ
150kʎ
No.
1
2
3
4
5
6
7
8
ýýýýýýFunction
Output
Non Connection
Error Amp Output
Output voltage feedback
Enable
Frequency setting resistor connection
Ground
Power supply input
Pin name
SW
N.C.
FB
INV
EN
RT
GND
V
IN
2010.02 -
Rev. B
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BD9778F, BD9778HFP, BD9001F, BD9781HFP