NCP1015
http://onsemi.com
19
A 7.0 W NCP1015−based Flyback Converter Featuring Low Standby Power
Figure 29 shows another typical application showing a
NCP1015−65 kHz operating in a 7 W converter up to 70°C
of ambient temperature. We can grow−up 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.
1 8
2
3
4
7
5
V
CC
NC
NC
FB
GND
DRAIN
Vbulk
C2
47 mF/
450 V
+
1N4148
D4
R2
3.3 k
+
C10
33 mF/25 V
R4 22
NCP1015
+
100 mF/10 V
C3
C9
1 nF
C8
10 nF
400 V
R7
100 k/
1 W
D3
MUR160
T1
12 V @
0.5 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
NC
Figure 29. A Typical Converter Delivering 5 W from a Universal Mains
Measurements have been taken from a demonstration
board implementing Figure 12 12’s sketch and the following
results were achieved, with either the auxiliary winding in
place or through the Dynamic Self−Supply:
V
in
= 230 Vac, auxiliary winding, P
out
= 0, P
in
= 60 mW
V
in
= 100 Vac, auxiliary winding, P
out
= 0, P
in
= 42 mW
V
in
= 230 Vac, Dynamic Self−Supply, P
out
= 0, P
in
=
300 mW
V
in
= 100 Vac, Dynamic Self−Supply, P
out
= 0, P
in
=
130 mW
P
out
= 7 W, h = 81% @ 230 Vac, with aux winding
P
out
= 7 W, h = 81.3% @ 100 Vac, with aux winding
For a quick evaluation of Figure 29 application example,
the following transformers are available from Coilcraft:
A9619−C, L
p
= 3 mH, Np : Ns = 1: 0.1, 7 W application on
universal mains, including auxiliary winding, NCP1015−
65 kHz
A0032−A, L
p
= 6 mH, Np : Ns = 1: 0.055, 10 W application
on European mains, DSS operation only, NCP1015−65 kHz
Coilcraft
1102 Silver Lake Road
CARY, IL 60013
Email: info@coilcraft.com
Tel. : 847−639−6400
Fax.: 847−639−1469
