www.powerint.com

C

5/03

DI-40

WORLD HEADQUARTERS

AMERICAS

Power Integrations, Inc.

San Jose, CA 95138 USA

Customer Service:

Phone:

+1 408-414-9665

Fax:

+1 408-414-9765

e-mail: usasales@powerint.com

CHINA

Power Integrations International

Holdings, Inc.

China

Phone:

+86-755-8367-5143

Fax:

+86-755-8377-9610

e-mail: chinasales@powerint.com

SINGAPORE

Power Integrations, Singapore

Republic of Singapore 308900

Phone:

+65-6358-2160

Fax:

+65-6358-2015

e-mail: singaporesales@powerint.com

JAPAN

Power Integrations, K.K.

Keihin-Tatemono 1st Bldg.

Japan

Phone:

+81-45-471-1021

Fax:

+81-45-471-3717

e-mail: japansales@powerint.com

EUROPE & AFRICA

Power Integrations (Europe) Ltd.

United Kingdom

Phone:

+44-1344-462-300

Fax:

+44-1344-311-732

e-mail: eurosales@powerint.com

KOREA

Power Integrations

International Holdings, Inc.

Seoul, Korea

Phone:

+82-2-782-2840

Fax:

+82-2-782-4427

e-mail: koreasales@powerint.com

TAIWAN

Power Integrations

International Holdings, Inc.

Taipei, Taiwan

Phone:

+886-2-2727-1221

Fax:

+886-2-2727-1223

e-mail: taiwansales@powerint.com

INDIA (Technical Support)

Innovatech

Bangalore, India

Phone:

+91-80-226-6023

Fax:

+91-80-228-9727

e-mail: indiasales@powerint.com

APPLICATIONS HOTLINE

APPLICATIONS FAX

World Wide +1-408-414-9660

World Wide +1-408-414-9760

Table 1. Transformer Construction Information.

Figure 2. Efficiency vs. Output Power.

80

70

65

75

95

85

90

0

510

15

20

Output Power (W)

60

TRANSFORMER PARAMETERS

Core Material

PR1408

EPCOS N87 material ungapped

Bobbin

P1408 8 pin

(B&B B-096 or equivalent)

Turns

Bias: 6T, 32 AWG

Primary: 7T + 7T, 2 x 28 AWG

Secondary: 2T, 4 x 26 AWG

Primary Inductance

392 µH ± 25%

Leakage Inductance

1 µH (maximum)

Primary Resonant

Frequency

3 MHz (minimum)

Winding Order

(Pin Numbers)

Bias: (3-2), Tape

Primary: (4-FL), Tape

Secondary: (6, 7-9, 10), Tape

Primary: (FL-10), Tape

OUTPUT INDUCTOR PARAMETERS

Core

EPCOS N87 material

2

Bobbin

P1408 8 pin

(B&B B-096 or equivalent)

Winding Details

Bias: 10T, 32 AWG

Main: 4T, 4 x 26 AWG

Inductance Pins 5,6-7,8

3.3 µH ± 10%

Winding Order

(Pin Numbers)

Bias: (1-2), Tape

Main: (7,8-5,6), Tape

Table 2. Output Inductor Construction Information.

• Optocoupler U2 should have controlled CTR of 100-200%

for optimum loop stability.

• Size transformer reset components C8 and R5, and the Q1

gate capacitance to assure transformer reset at minimum

operating voltage without exceeding 170 V drain voltage

at high line.

• Set Zener VR1 clamp voltage to 150 V to guarantee both

transformer reset and limit DRAIN voltage below BV

• Scale primary side forward bias winding to provide

12 V to 15 V at minimum input voltage, nominal load.

• Secondary choke winding provides 5 V at nominal load.

•Main primary power return should be connected to the

DPA-Switch tab, not to the SOURCE pin.

• Consult AN-31 for additional design tips.

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 (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, Inc.

PI Expert and DPA-Switch are trademarks of Power Integrations, Inc. ©Copyright 2003, Power Integrations, Inc.