DI-89
DI-123
80
70
60
50
40
30
20
10
0
•
Maximize the value of R8 and minimize the value of C4
for the lowest no-load consumption. However, verify
that the peak drain voltage is <650 V at high line, under
maximum overload conditions.
Select transformer wire gauge sizes so that each winding
layer occupies the full bobbin width. This lowers leakage
inductance and improves output cross regulation.
Use option to add E-Shield windings in PI Transformer
Designer software to reduce conducted EMI noise
generation.
EN55022B Limits
QP
AV
•
•
•
QP
AV
To lower the no-load power consumption even further,
use an optional bias supply circuit to feed the rated data
sheet current (through a series resistor) to the
BP/M pin of U1.
-10
-20
0.15
1.0
10.0
100.0
MHz
Load
Range
(mA)
Regulation (%)
-2 -1.5 -1 -0.5 0.5
Figure 3. Worst Case Conducted EMI at 230 VAC, Full Load
Output Return Grounded.
Output
(V)
0
1
1.5
2
5
50-250
88-350
TRANSFORMER PARAMETERS
24
EF20 TDK PC40, or equivalent
Core Material
ALG of 323 nH/T2
Table 1. Worst Case Output Cross Regulation at 185 VAC
Output Loads Varied as Shown and Maximum
Deviation Recorded.
EF20, 10 pin (5+5), horizontal
Bobbin
Pin Shine P-2015 or equivalent
80
79
78
77
76
75
Shield: 15T, 2 × 31 AWG
Primary: 36T + 35T, 33 AWG
Shield: 4T, 5 × 29 AWG
Winding Details 5 V: 3T, 4 × 26 AWG T.I.W.
24 V: 11T, 26 AWG T.I.W.
(4 × 26 AWG = quadfilar 26
AWG)
Apply 2 mm tape margin to both
sides of bobbin
Winding Order
Shield (1-NC), tape, Primary
(Pin Numbers)
(3-1), Shield (NC-1), 5 V (6-8),
24 V (10-6)
185
205
225
245
265
Primary: 1.62 mH ±5%
Inductance
AC Input Voltage (V)
Leakage: 50 µH maximum
Figure 2. Full Load Efficiency vs Input Voltage.
Primary Reso-
800 kHz (minimum)
nant Frequency
Table 2. Transformer Construction Information.
TIW = Triple Insulated Wire, NC = No Connect
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illustrated herein (transformer construction and circuits external to the products) may be covered by one or more U.S.
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Rev. A 09/06
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