Samsung S3F84A5 User Manual

APPLICATION NOTE

S3F84A5
An LED Lighting System
January 2010
Revision 0.00
Confidential Proprietary of Samsung Electronics Co., Ltd
Copyright © 2010 Samsung Electronics, Inc. All Rights Reserved

Important Notice

Samsung reserves the right to make changes in its products or product specifications with the intent to improve function or design at any time and without notice and is not required to update this documentation to reflect such changes.
This publication does not convey to a purchaser of semiconductor devices described herein any license under the patent rights of Samsung or others.
Samsung makes no warranty, representation, or guarantee regarding the suitability of its products for any particular purpose, nor does Samsung assume any liability arising out of the application or use of any product or circuit and specifically disclaims any and all liability, including without limitation any consequential or incidental damages.
"Typical" parameters can and do vary in different applications. All operating parameters, including "Typicals" must be validated for each customer application by the customer's technical experts.
Samsung products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, for other applications intended to support or sustain life, or for any other application in which the failure of the Samsung product could create a situation where personal injury or death may occur.
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S3F84A5 An LED Lighting System Application Note, Revision 0.00
Copyright 2010 Samsung Electronics Co., Ltd.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electric or mechanical, by photocopying, recording, or otherwise, without the prior written consent of Samsung Electronics.
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Revision History

Revision No. Date Description Author(s)
0 Jan. 20, 2010 - Initial draft Wei Ningning

Table of Contents

1 Overview of HPLED Lighting Control System............................................7
1.1 Pin Assignment in S3F84P4........................................................................................................................7
1.2 Key Features of S3F84P4............................................................................................................................8
1.3 System Principle ..........................................................................................................................................8
1.3.1 Buck Circuit...........................................................................................................................................9
1.3.2 Summary ..............................................................................................................................................9
1.3.3 Constant Current Control....................................................................................................................10
2 Hardware Implementation ..........................................................................11
2.1 System Diagram and Circuit......................................................................................................................11
2.2 Components Selection...............................................................................................................................12
2.2.1 Select the Inductance (L1) for the Requirement of Current Ripple....................................................12
2.2.2 Select the Capacitance (C2) for the Requirement of Voltage Ripple.................................................12
3 Software Implementation............................................................................13
4 System Validation .......................................................................................15
5 Appendix......................................................................................................17
5.1 BOM List of Key Circuit..............................................................................................................................17
5.2 Appendix 2: Source Code..........................................................................................................................17

List of Figures

Figure Title Page Number Number
Figure 1-1 S3F84P4 Pin Assignment.....................................................................................................................7
Figure 1-2 Simplified Buck Circuit..........................................................................................................................9
Figure 1-3 Current on load.....................................................................................................................................9
Figure 1-4 HKP-D1W1 Forward Voltage, Forward Current, and Relative Luminous Flux...................................10
Figure 2-1 Control Circuit.....................................................................................................................................11
Figure 3-1 Software Implementation Diagram .....................................................................................................13
Figure 3-2 Way to change PWM duty cycle.........................................................................................................14
Figure 4-1 Waveform for HPLED forward voltage and current............................................................................15

List of Tables

Table Title Page Number Number
Table 4-1 System validation of efficiency.............................................................................................................16
Table 5-1 BOM list of Key Circuit.........................................................................................................................17
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