Power DI-41 43 w, 100/115 vac multi-output set-top box power supply Datasheet

®
Design Idea DI-41
®
TOPSwitch-GX 43 W, 100/115 VAC
Multi-output Set-top Box Power Supply
Application
Device
Power Output
Input Voltage
Output Voltage
Topology
Set-top Box
TOP247Y
43 W cont. / 57 W pk
90-132 VAC
3.3 V, 5 V, 12 V, 18 V, 33 V
Flyback
Design Highlights
Operation
• Low cost, low component count solution
• Excellent output voltage tracking and cross-regulation - no
linear regulators required
• High efficiency, >71% at 90 VAC
• Line undervoltage detection (UV) and power system surge
protection (OV)
• Meets CISPR22B/EN55022B conducted EMI limits
• Differential and common mode surge immunity to 4 kV
(EN61000-4-5)
• 100 kHz ring wave immunity to 4 kV (IEEE C62.41)
The design in Figure 1 utilizes the TOP247Y and takes
advantage of many of the TOPSwitch-GX features. Line UV
and OV (100 V and 450 V, respectively) are implemented
using a single 2 MΩ resistor (R1). Undervoltage eliminates
output glitches and overvoltage provides protection for both
short duration transients and long duration power system
surges. Resistor R4 programs the internal current limit of U1
to 80% of nominal, limiting overload power.
T1
R6
10 Ω
14
D7
UF4003
L7
Bead
8
C24
R15 0.1 µF
10 Ω 50 V
C5
R2
68 kΩ 1 nF
2 W 1 kV
C6
2.2 nF
Y1
D10
BYV32-200
1
VR1
P6KE200
D2
3, 4
D1
C13, C14
1200 µF
35 V
D11
MBR1045
C22
0.1 µF
50 V
C16, 17
1200 µF
35 V
18 V, 0.5 A
12 V,
0.6 A/1.8 A pk
C12
100 µF
25 V
11
10
C10
220 µF
25 V
L3
3.3 µH, 5 A
C11
390 µF
35 V
9
D1-D4
RL206
2 A, 800 V
33 V, 0.03 A
C8
10 µF
50 V
L2
3.3 µH, 5 A
C9
1000 µF
25 V
D9
UF5402
12
L6
33 µH, 0.2 A
C7
47 µF
50 V
D8
UF5402
13
The key performance characteristic of the circuit shown is the
excellent output voltage tracking and cross-regulation. Two
techniques are used to properly center the output voltages.
The extra voltage drop of the ultra-fast rectifier D10 (used
instead of a Schottky) centers the 5 V output at precisely 5 V
R14
5.6 kΩ
0.5 W
L4
3.3 µH
5A
5 V, 3.2 A
L5
C15
3.3 µH 220 µF
5A
16 V
3.3 V, 3 A
C18
220 µF
16 V
RTN
D5
1N4937
D4
D3
L1
20 mH
1.3 A
C1
0.22 µF
X2
t°
90 - 132
VAC
7
D
RT1
10 Ω
3.2 A
L
D6
1N4148
S
X
6
C3
1 µF
50 V
F
R8
1 kΩ
C19
0.1 µF
50 V
R10
9.53 kΩ
1%
R12
18 kΩ
R13
15 kΩ
1%
C
C3
0.1 µF
50 V
R3
6.8 Ω
C20
22 µF
50 V
C5
47 µF
16 V
N
Figure 1. TOPSwitch-GX 43 W Continuous, 57 W Peak Set-Top Box Power Supply.
DI-41
C21
0.1 µF
50 V
U2
LTV817
TOPSwitch-GX
CONTROL
U1
TOP247Y
R4
9.09 k
1%
R7
150 Ω
5
R1
2 MΩ
1/2 W
RV1
275 V
14 mm
F1
3.15 A
L
C2
150 µF
200 V
www.powerint.com
R9
3.3 kΩ
U3
TL431CLP
R11
10 kΩ
1%
PI-3389-091702
September 2002
DI-41
and DC stacking is used to improve the regulation of 12 V,
18 V, and 30 V outputs. Ferrite bead L7 is placed in series with
the 12 V, 18 V and 30 V output windings to improve centering
and cross-regulation of these outputs.
TRANSFORMER PARAMETERS
Core Material
ERL28, Nippon ceramic
NC-2H material or equivalent,
gapped for ALG = 128 nH/T2
Bobbin
ERL28 vertical, 14 pins,
Jinbo Industrial
JB-0039 or equivalent
Winding Details
Primary: 30T + 23T, 25 AWG
Shield: 1T, 0.6" x 0.001" Cu foil
Bias: 7T, 2 x 27 AWG
3.3 V: 2T, 0.6" x 0.005" Cu foil
5 V: 1T, 0.6" x 0.005" Cu foil
12 V: 4T, 2 x 27 AWG
18 V: 3T, 2 x 27 AWG
33 V: 6T, 27 AWG
(2 x 27 AWG = Bifilar 27 AWG)
Winding Order
(Pin Numbers)
Apply 3.2 mm tape margin to
both sides of bobbin
Primary (4-3), tape, Shield (1-NC),
tape, Bias (6-7), 3 x tape, 5 V (9-11),
3.3 V (11-10), tape, 12 V (12-8),
18 V (13-12), 33 V (14-13),
3 x tape, Primary (3-1), 3 x tape
Inductance
Primary: 356 µH,
Leakage: 11 µH (maximum)
Primary Resonant
Frequency
650 kHz (minimum)
Frequency jittering provides large EMI margins with simple
filtering. Primary soft-start minimizes component stress during
start-up and a soft-finish capacitor (C20) eliminates start-up
output overshoot.
Key Design Points
• Use KRP (Ripple-to-peak current ratio) in the range of
0.4–0.6 for higher efficiency, and tighter cross-regulation.
Use VOR (reflected output voltage) of 90 V to 110 V for
optimum performance.
• PCB traces which carry high switching currents should be
short and wide to reduce EMI.
• Reduce leakage inductance and improve cross-regulation
by filling each winding layer across the entire width of the
bobbin.
• Resistor R14 provides a small amount of pre-load on the
33 V output to prevent peak charging due to leakage
spikes.
• R5 and C5 reduce power dissipation in VR1.
Voltage Load
(V)
3.3
5
12
30
Range
(Amp) -8 -7 -6
1-3
1-3.2
0.3-0.6
0.01-0.03
Regulation (%)
-5
-4
-3
-2
-1
0
Table 1. Transformer Design Parameters.
1
2
3
Table 2. Worst Case Output Cross Regulation - Outputs Taken
from Minimum to Maximum Load and Line from 85 VAC
to 132 VAC.
For the latest updates, visit our Web site: www.powerint.com
Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability.
Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it convey any
license under its patent rights or the rights of others. The products and applications illustrated herein may be covered by one or more U.S.
and foreign patents or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A complete list of Power
Integrations’ patents may be found at www.powerint.com.
The PI Logo, TOPSwitch, TinySwitch and EcoSmart are registered trademarks of Power Integrations, Inc.
PI Expert is a trademark of Power Integrations, Inc. ©Copyright 2002, Power Integrations, Inc.
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