NCP1010, NCP1011, NCP1012, NCP1013, NCP1014
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20
A 7.0 W NCP1013−based Flyback Converter
Featuring Low Standby Power
Figure 32 depicts another typical application showing a
NCP1013−65 kHz operating in a 7.0 W converter up to
70°C of ambient temperature. We can increase the output
power since an auxiliary winding is used, the DSS is
disabled, and thus offering more room for the MOSFET. In
this application, the feedback is made via a TLV431 whose
low bias current (100 mA min) helps to lower the no−load
standby power.
Figure 32. A Typical Converter Delivering 7.0 W from a Universal Mains
1 8
2
3
4
7
5
V
CC
NC
GND
FB
GND
D
Vbulk
C2
47 mF/
450 V
+
1N4148
D4
R2
3.3 k
+
C10
33 mF/25 V
R4 22
NCP1013P06
+
100 mF/10 V
C3
C9
1 nF
C8
10 nF
400 V
R7
100 k/
1 W
D3
MUR160
T1
12 V @
0.6 A
GND
D2
MBRS360T3
+ +
100 mF/16 V
C7
+
C6 C8
470 mF/16 V
R5
39 k
R3
1 k
IC1
SFH6156−2
C4
100 nF
IC2
TLV431
R6
4.3 k
C5
2.2 nF
Y1 Type
T1
Aux
L2
22 mH
GND
Measurements have been taken from a demonstration
board implementing the diagram in Figure 32 and the
following results were achieved, with either the auxiliary
winding in place or through the Dynamic Self−Supply:
Vin = 230 Vac, auxiliary winding, Pout = 0, Pin = 60 mW
Vin = 100 Vac, auxiliary winding, Pout = 0, Pin = 42 mW
Vin = 230 Vac, Dynamic Self−Supply, Pout = 0,
Pin = 300 mW
Vin = 100 Vac, Dynamic Self−Supply, Pout = 0,
Pin = 130 mW
Pout = 7.0 W, h = 81% @ 230 Vac, with auxiliary winding
Pout = 7.0 W, h = 81.3 @ 100 Vac, with auxiliary winding
For a quick evaluation of Figure 32 application example,
the following transformers are available from Coilcraft:
A9619−C, Lp = 3.0 mH, Np:Ns = 1:0.1, 7.0 W
application on universal mains, including auxiliary winding,
NCP1013−65kHz.
A0032−A, Lp = 6.0 mH, Np:Ns = 1:0.055, 10 W
application on European mains, DSS operation only,
NCP1013−65 kHz.
Coilcraft
1102 Silver Lake Road
CARY IL 60013
Email: info@coilcraft.com
Tel.: 847−639−6400
Fax.: 847−639−1469
