MC34166 ON Semiconductor, MC34166 Datasheet - Page 14

• Manufacturer Part Number: MC34166
• Description: (MC33166 / MC34166) Step-Up/Down/Inverting Switching Regulators
• Manufacturer: ON Semiconductor

115 VAC
The MC34166 can be used cost effectively in off−line applications even though it is limited to a maximum input voltage of 40 V. Figure 28 shows
a simple and efficient method for converting the AC line voltage down to 24 V. This preconverter has a total power rating of 125 W with a conversion
efficiency of 90%. Transformer T
self−oscillates at 50 kHz and is controlled by the saturation characteristics of T
accurate independently regulated outputs for a distributed power system.
Filter
RFI
T
T
T
T
T
1
1
1
1
1
= Core and Bobbin − Coilcraft PT3595
=
=
=
=
Primary − 104 turns #26 AWG
Base Drive − 3 turns #26 AWG
Secondaries − 16 turns #16 AWG
Total Gap − 0.002″
1N5404
100k
+
50
1
provides output isolation from the AC line and isolation between each of the secondaries. The circuit
220
Figure 29. D
80
70
60
50
40
30
Power Dissipation versus P.C.B. Copper Length
0
MJE13005
1N4937
0.047
1N4003
Vertically
Mounted
Free Air
5.0
Figure 28. Off−Line Preconverter
3.3
2
PAK Thermal Resistance and Maximum
MC34166, MC33166
L, LENGTH OF COPPER (mm)
http://onsemi.com
10
+
T
2
Minimum
Size Pad
100
P
R
14
15
D(max)
qJA
0.01
for T
T
T
T
T
T
2
2
2
2
2
= Core − TDK T6 x 1.5 x 3 H5C2
=
=
=
=
A
14 turns center tapped #30 AWG
MC34166 and MJE13005 − 5903B
MBR20100CT − 5925B
2
20
Heatsink = AAVID Engineering Inc.
. Multiple MC34166 post regulators can be used to provide
= +50°C
T1
L
2.0 oz. Copper
Î Î Î Î
Î Î Î Î
Î Î Î Î
Î Î Î Î
25
L
MBR20100CT
MBR20100CT
MBR20100CT
0.001
0.001
0.001
0.001
0.001
0.001
30
3.5
3.0
2.5
2.0
1.5
1.0
1000
1000
1000
+
+
+
Step−Down
Step−Down
Step−Down
MC34166
Converter
MC34166
Converter
MC34166
Converter
+
+
+
Output 1
Output 2
Output 3