DI-35 [POWERINT]
16 W Audio Amplifier Power Supply; 16 W音频放大器电源
| 型号： | DI-35 |
| 厂家： | 
Power Integrations |
| 描述： | 16 W Audio Amplifier Power Supply |
| 文件： | 总2页 (文件大小：326K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Design Idea DI-35
®
TOPSwitch-GX
16 W Audio Amplifier Power Supply
Application
Device
Power Output
Input Voltage
Output Voltage
Topology
Audio Amplifier
TOP245P
16 W (35 W Peak)
85-265 VAC
16 V
Flyback
Design Highlights
The EMI filter has been significantly simplified to three
components (L1, CX1 and CY1), thanks to the built-in
frequency jitter function of the TOPSwitch-GX family.
• No heatsinks required!
• 77% efficiency (min), at 85 VAC input/35 W output
• Low no-load input power: < 0.7 W at 230 VAC input
• Low component count: 37, excluding I/O connectors
• Stable operation with or without 10,000 µF output buffer
capacitor
• Robust transformer design enables 35 W peak power
• Meets CISPR22B EMI with >10 dB of margin
• Ideal for both class AB and class D audio amplifiers,
6 channel Dolby Digital with 6 ohm speakers
The RCD network of C4, R3, R4, and D5 limits (clamps) the
peak voltage that the U1-DRAIN sees. A glass-passivated
normal recovery diode (D5) recycles stored leakage energy,
increasingoverallefficiency.DRAINringingisdampenedby
R4 (necessary when a normal recovery diode is used).
The bias winding provides operating power and feedback
current to the CONTROL pin of U1. The U2-LED, R8 and
VR1 comprise the feedback circuit that senses the output
voltage. ThecurrentthroughtheU2-LEDregulatestheoutput
voltage by modulating the feedback current that flows into
the CONTROL pin of U1.
Operation
Many of the built-in TOPSwitch-GX features have been used
to reduce the component count, transformer size and overall
cost of this universal input flyback power supply. Designed
around a TOP245P (DIP-8 package), the device uses PCB
copper for its heatsink, eliminating the costs of both a heatsink
and the installation labor. Output diode D7 is also cooled the
same way.
Key Design Points
• Ensure that the control loop has enough phase margin at
the extremes of the rated input voltage and output load,
both with and without the output buffer capacitor.
• A 5% VR1 should be acceptable for an audio amplifier.
Greater accuracy will require a 2% VR1.
Resistors R1 and R2 set the nominal under-voltage (UV)
lockout and overvoltage (OV) shutdown limits to 84 V and
378 V, respectively. UV lockout protects the supply from
overheating at low line and eliminates power-up and power-
down glitches. OV shutdown protects the power supply from
line surges.
• OV and UV thresholds are determined by:
VOV = 225 µA • (R1+R2) and VUV = 50 µA • (R1+R2).
CY1
R6
C6
2.2 nF
(Safety)
33 Ω 470 pF
1/4 W 100 V
R3
C4
C9
100 µF
25 V
L2
3.3 µH
16 V, 1 A /
2.2 A
200 kΩ 1 nF
1/2 W 1 kV
1
3
9,10
6,7
D1-D4
1N4007
D7
SB5100
R1
C1
1 MΩ
100 µF
400 V
R7
10 Ω
C7
C8
RTN
470 µF 470 µF
4
5
R2
1 MΩ
25 V
25 V
R4
33 Ω
C5
1 µF
50 V
R8
150 Ω
1/4 W
D5
L1
6.8 mH
0.8 A
T1
1N4007G
D6
BAV20
TOPSwitch-GX
R10
1 k
D
S
M
U1
TOP245P
C
CX1
CONTROL
220 nF
250 VAC
U2
PC817A
R5
3.3 Ω
F1
C2
100 nF
50 V
3.15 A
VR1
IN5244B
5%
C10
47 µF
25 V
250 V
C3
100 µF
16 V
85-265
VAC
L
N
PI-3731-070704
Figure 1. Audio Amplifier Power Supply.
July 2004
DI-35
www.powerint.com
DI-35
• Keep power loop layouts (primary and secondary) tight to
minimize noise (EMI and output ripple) and power loss.
• At least 10 cm2 of PCB copper area should be used for
heatsinking.
• 10,000 µF output buffer capacitor, standard ESR,
improves multi-channel audio transient capability.
16.1
TRANSFORMER PARAMETERS
16
15.9
15.8
15.7
Nippon Ceramic EF-25-NC-2H
Core Material
ALG of 247 nH/T2
Miles-Platts FE0100 with
Bobbin
TBS-601 terminals
15.6
15.5
15.4
15.3
15.2
15.1
15
Primary: 65T, 2 layers, 28 AWG
Secondary: 9T, 2 x 26 AWG,
triple insulated
Winding Details
Bias: 7T, 2 x 28 AWG
Primary: 3-1, tape
Winding Order
Secondary: 9, 10-6,7, tape,
(pin numbers)
Bias: 4-5, tape 3L
0
0.5
1
1.5
2
2.5
Primary
IOUT (A)
1059 µH ±10%
Inductance
Figure 2. 115 VAC V-I Curve.
Primary Resonant
0.75 MHz (min)
Frequency
7
Leakage
28 µH (max)
Inductance
6
5
4
Table 1. Transformer Construction Information.
THERMAL TEST RESULTS
Thermal test load current is 1 A for 30 ms, 2.2 A for 10 ms
3
2
T (°C) at
T (°C) at
265 VAC
Test Case
85 VAC
T1 (Transformer)
U1 (TOP245P)
57
64
58
41
59
51
59
40
1
0
1 A
2.2 A
D7 (Op Rectifier)
C8 (Op Capacitor)
-1
50
100
0
Table 2. Thermal Test with Pulsed Load of Figure 3. 25 °C
Time (ms)
Ambient, Open Frame, 85 VAC and 265 VAC Input.
Figure 3. Load Current for Thermal Test (10 ms/div).
For the latest updates, visit www.powerint.com
Power Integrations may make changes to its products at any time. Power Integrations has no liability arising from your use of any information, device or circuit
described herein nor does it convey any license under its patent rights or the rights of others. POWER INTEGRATIONS MAKES NO WARRANTIES HEREIN AND
SPECIFICALLY DISCLAIMS ALL WARRANTIES INCLUDING, WITHOUT LIMITATIONS, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF THIRD PARTY RIGHTS. The products and applications illustrated herein (including circuits external to the
products and transformer construction) 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, LinkSwitch and EcoSmart are registered trademarks of Power Integrations. PI Expert and DPA-Switch
are trademarks of Power Integrations. Copyright 2004, Power Integrations
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B
7/04
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