Samsung S3F84A5 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 The information in this publication has b een carefully checked and is believed to be entirely a ccurate at the time of publication. Samsung assumes no responsibility, however, for possible errors or omissions, or for any consequences resulting from the use of the information contained h erei n. Samsung reserves the right to make c[...]

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

Table of Contents 1 Overview of HPLED Light ing Control System ............................................ 7 1.1 Pin Assignment in S3F84P4 .................................................................................................. ......................7 1.2 Key Features of S3F84P4 ...........................................................[...]

List of Figures Figure Title Page Number Number Figure 1-1 S3F84P 4 Pin Assignment ............................................................................................ .........................7 Figure 1-2 Simplif ied Buck Circuit ........................................................................................... ...................[...]

List of Tables Table Title Page Number Number Table 4-1 System va lidation of efficiency .................................................................................... .........................16 Table 5-1 BOM lis t of Key Circuit ............................................................................................ ....................[...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 1 OVER VIEW OF HPLED LIGHTING CONTROL SYSTEM 1 OVER VIEW OF HPLED LIGHTING CONTROL SYSTEM A light-emitting diode (LED) is a semiconductor light source that presents several advantages over traditional light (like incandescent) sou rces such as lower energy co nsumption , longer lifetime , improved robustness, s[...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 1 OVER VIEW OF HPLED LIGHTING CONTROL SYSTEM 1.2 KEY FEATURES OF S3F84P4 The key features in S3F84P4 include:  4 kbyte Flash ROM or 208 Byte SRAM  6+6 PWM x 1  10-bit ADC x 4  8-bit Basic Timer (can b e use d as watchdog timer)  16-bit Timer0 (can be used as Time r A or B, the two 8-bit Timers ) [...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 1 OVER VIEW OF HPLED LIGHTING CONTROL SYSTEM 1.3.1 BUCK CIRCUIT Figure 1-2 Simp lified Buck Circuit Buck circuit works when a switch si gnal turns on the transi stor (Q). The DC po we r then starts to charge the coil (L). When the current reaches a predefined level, change t he transistor state from On to Off u[...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 1 OVER VIEW OF HPLED LIGHTING CONTROL SYSTEM 1.3.3 CONSTANT CURRENT C ONT ROL Refer to the HKP-D1W1 datasheet to see the relation ship of forward voltage, forward cu rrent, and relative luminous flux. Figure 1-4 HKP-D1W1 Forward Voltage, Forward Current, and Relativ e Luminous Flux As shown in Figure 1-4 , desc[...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 2 HARDWARE IMPLEMENTATION 2 HARDW ARE IMPLEMENT A TION 2.1 SYSTEM DIAG RAM AND CIRCUIT Figure 2-1 Control Circuit As shown in Figure 2-1 , the Buck Circuit comprise of Q1, L1, D1, a nd C2. The o utput of PWM turns on/off the transistor (Q1). The cu rrent over HPLED is sensed by a 1ohm power re sistor. It then g[...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 2 HARDWARE IMPLEMENTATION 2.2 COMPONENTS SELECTION Assume the following two conditions: ( 1 ) 3.5 0.35 3.85 OF W F W V V I ohm V      5 I VV  If non-divided system clock is selected as the cl ock so urce of the 6+6 PWM, its base frequency is 6 125 2 OSC f KHz  . 2.2.1 SELECT THE INDUCTAN[...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 3 SOFTWARE IMPLEMENTATION 3 SOFTW ARE IMPLEMENT A TION S amsun g Con f idential 13 Figure 3-1 shows the software implementation. Initialization Value > max ? ADC sampling Vale < min ? Decrease PWM duty cy cle Increase PWM duty cy cle Figure 3-1 Softw are Implementation Diagram Since the PWM in S3F84P4 is [...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 3 SOFTWARE IMPLEMENTATION N Y Decrease PWM duty cycle Start PWMEX>=100B? PWMEX = 0xFF PWMDATA - =1 End PWMEX - =1 N Y Increase PWM duty cycle Start PWMEX>= 11111100B? PWMEX + = 1 End PWMEX = 0 PWMDATA + =1 Figure 3-2 Wa y to change PWM duty cycle  Change rate of PWM duty cycle: If PWM in S3F84P4 is 6+6[...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 4 SYSTEM VALIDATION 4 SYSTEM V ALIDA TION Figure 4-1 shows the current ripple and voltage rippl e test wa veform. Red and blue colors sp ecify the cu rrent and voltage, respectively. Figure 4-1 Waveform for HPLED forward voltage and current () (I ) s fd s s ps MCU ps V VV R efficienc y I V    5 p[...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 4 SYSTEM VALIDATION Table 4-1 System validation of efficiency #1 #2 #3 #4 #5 BD1 BD2 BD1 BD2 BD1 BD2 BD1 BD 2 BD1 BD2 Ips (power supply) (mA) 300 288 306 285 300 288 309 290 308 304 Imcu (m A) (MCU 供 电 LED) 18 19 18 19 18 19 18 19 18 19 3.82 3.6 3.85 3.60 3.86 3.6 3.90 3.59 3.90 3.65 Vfd V ） 357 340 359 3[...]

S3F84P4_AN_REV0.00 (PRELIMINARY SPEC) 5 APPENDIX S amsun g Con f idential 17 5 APPENDIX 5.1 BOM LIST OF KEY CIRCUIT Table 5-1 shows the BOM l ist of key circ uit . Table 5-1 BOM list of Key Circuit Reference Description Manufacturer Part number R1 1K ohms R2 10 ohms Rs Current sensi ng Re sistor VISHAY  WSR21R000FEA C1 104 C2 47uF Tantalu m Capa[...]