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Typical Performance Characteristics

6

Typical Performance Characteristics

Figure 4. Efficiency vs LED Current

Figure 5. Efficiency vs LED Current

(V

IN

= 5 V, V

BOOST

Derived from V

IN

)

(V

IN

= 12 V)

Figure 6. Efficiency vs Input Voltage

Figure 7. Switching Waveforms

(I

F

= 1A)

5

SNVA271B – October 2007 – Revised April 2013

AN-1685 LM3405A Demo Board

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Copyright © 2007–2013, Texas Instruments Incorporated

Summary of Contents for LM3405A

Page 1: ...MHz 1A Constant Current Buck LED Driver with Internal Compensation in Tiny SOT and MSOP PowerPAD Packages Data Sheet SNVS508 2 Connecting to LED Array The LM3405A demo board includes a female 6 position SIP connector P1 as well as two standard 72mil turret connectors for the cathode and anode connections of the LED array Solid 18 or 20 gauge wire with about 1cm of insulation stripped away makes a ...

Page 2: ... 4 5 D4 Not installed GND ANODE of First LED CATHODE of Last LED IF PWM Dimming www ti com Figure 1 LM3405A Demo Board Schematic Figure 2 PWM Dimming of LEDs Figure 2 AN 1685 LM3405A Demo Board SNVA271B October 2007 Revised April 2013 Submit Documentation Feedback Copyright 2007 2013 Texas Instruments Incorporated ...

Page 3: ...e 3 Average LED Current versus Duty Cycle of PWM Dimming Signal at PWM Terminal 3 SNVA271B October 2007 Revised April 2013 AN 1685 LM3405A Demo Board Submit Documentation Feedback Copyright 2007 2013 Texas Instruments Incorporated ...

Page 4: ...2A AVX C4 0 1 µF 16 V X7R 0805 GRM219R71C104KA01D Murata C5 1 µF 35 V X7R 0805 GMK212BJ105KG T Taiyo Yuden D1 Schottky 40 V 1A SMA SS14 E3 61T Vishay D2 Schottky 30 V 200 mA SOD 323 BAT54WS TP Micro Commercial Co D3 5 1 V 0 35W SOT23 MMBZ5231B 7 F Diodes D4 Not installed R1 0 5W 0 2 Ω 1 2010 WSL2010R2000FEA Vishay R2 100 kΩ 1 8W 1 0805 CRCW0805100KFKEA Vishay R3 1 0 kΩ 1 1 8W 0805 CRCW08051K00FKEA...

Page 5: ...LED Current Figure 5 Efficiency vs LED Current VIN 5 V VBOOST Derived from VIN VIN 12 V Figure 6 Efficiency vs Input Voltage Figure 7 Switching Waveforms IF 1A 5 SNVA271B October 2007 Revised April 2013 AN 1685 LM3405A Demo Board Submit Documentation Feedback Copyright 2007 2013 Texas Instruments Incorporated ...

Page 6: ...gure 8 Startup During PWM Dimming Figure 9 Shutdown During PWM Dimming VIN 12 V IF 1A VIN 12 V IF 1A 6 AN 1685 LM3405A Demo Board SNVA271B October 2007 Revised April 2013 Submit Documentation Feedback Copyright 2007 2013 Texas Instruments Incorporated ...

Page 7: ...Figure 10 Top Layer and Top Overlay Figure 11 Bottom Layer and Bottom Overlay 7 SNVA271B October 2007 Revised April 2013 AN 1685 LM3405A Demo Board Submit Documentation Feedback Copyright 2007 2013 Texas Instruments Incorporated ...

Page 8: ...com Figure 12 Internal Plane 1 GND Figure 13 Internal Plane 2 VIN 8 AN 1685 LM3405A Demo Board SNVA271B October 2007 Revised April 2013 Submit Documentation Feedback Copyright 2007 2013 Texas Instruments Incorporated ...

Page 9: ... PWM L1 C2 R1 C5 VOUT 1 2 3 4 5 6 P1 7 12 6 1 R2 FB 2 3 4 5 D4 GND LED ANODE LED CATHODE www ti com Additional Circuit Configuration Schematics 8 Additional Circuit Configuration Schematics Figure 14 VBOOST Derived from VIN Figure 15 VBOOST Derived from VOUT 9 SNVA271B October 2007 Revised April 2013 AN 1685 LM3405A Demo Board Submit Documentation Feedback Copyright 2007 2013 Texas Instruments Inc...

Page 10: ...3 4 5 6 P1 7 12 6 1 R2 FB 2 3 4 5 D4 GND LED ANODE LED CATHODE a zener diode is connected in R3 spot Additional Circuit Configuration Schematics www ti com Figure 16 VBOOST Derived from VIN through a Series Zener Diode Figure 17 VBOOST Derived from VOUT through a Series Zener Diode 10 AN 1685 LM3405A Demo Board SNVA271B October 2007 Revised April 2013 Submit Documentation Feedback Copyright 2007 2...

Page 11: ...esponsible for compliance with all legal regulatory and safety related requirements concerning its products and any use of TI components in its applications notwithstanding any applications related information or support that may be provided by TI Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which anticipate dangerous consequences of failur...

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