ZLED7520

High Current 40V LED Driver with Internal Switch

Data Sheet

August 12, 2011

© 2011 Zentrum Mikroelektronik Dresden AG — Rev. 1.2

All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without

the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.

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Contents

1

IC Characteristics .......................................................................................................................................................... 6

1.1

Absolute Maximum Ratings ................................................................................................................................... 6

1.2

Operating Conditions ............................................................................................................................................. 6

1.3

Electrical Parameters............................................................................................................................................. 7

1.4

Typical Operation Graphs ...................................................................................................................................... 8

2

Circuit Description ....................................................................................................................................................... 13

2.1

ZLED7x20 Overview ............................................................................................................................................ 13

2.2

Control of Output Current via External Sense Resistor Rs .................................................................................. 13

2.3

Control of Output Current via an External DC Control Voltage on the ADJ Pin.................................................... 13

2.4

Control of Output Current via a PWM Signal on the ADJ Pin............................................................................... 14

2.5

Control of Output Current via a Microcontroller Signal on the ADJ Pin ................................................................ 14

2.6

Shutdown Mode ................................................................................................................................................... 14

2.7

ZLED7x20 Protection Features............................................................................................................................ 14

2.7.1

Thermal Shut-down Protection ..................................................................................................................... 14

2.7.2

LED Open Load Protection ........................................................................................................................... 14

3

Application Circuit Design............................................................................................................................................ 15

3.1

Applications.......................................................................................................................................................... 15

3.2

Thermal Considerations for Application Design ................................................................................................... 17

3.2.1

Temperature Effects of Load, Layout, and Component Selection................................................................. 17

3.2.2

3.3

External Component Selection............................................................................................................................. 17

3.3.1

Sense Resistor Rs ........................................................................................................................................ 17

3.3.2

Inductor L1.................................................................................................................................................... 18

3.3.3

Bypass Capacitor C1 .................................................................................................................................... 19

3.3.4

De-bouncing Capacitor C2............................................................................................................................ 21

3.3.5

Capacitor C3 for Reducing Output Ripple..................................................................................................... 21

3.3.6

Diode D1....................................................................................................................................................... 21

3.4

Application Circuit Layout Requirements ............................................................................................................. 21

4

ESD Protection............................................................................................................................................................ 22

5

Pin Configuration and Package ................................................................................................................................... 23

5.1

SOT89-5 Package Pin-out and Dimensions for the ZLED7020 ........................................................................... 23

5.2

DFN-5 Package Pin-out and Dimensions for the ZLED7320, ZLED7520 and ZLED7720 ................................... 25

6

Ordering Information ................................................................................................................................................... 27

7

Document Revision History ......................................................................................................................................... 27