LM3630A www.ti.com SNVS974 – APRIL 2013 LM3630A High-Efficiency Dual-String White LED Driver Check for Samples: LM3630A FEATURES DESCRIPTION • • • The LM3630A is a current mode boost converter which supplies the power and controls the current in up to two strings of 10 LEDs per string. Programming is done over an I2C-compatible interface. The maximum LED current is adjustable from 5 mA to 28.5 mA. At any given maximum LED current the LED brightness is further adjusted with 256 exponential or linear dimming steps. Additionally, pulsed width modulation ("PWM") brightness control can be enabled allowing for LED current adjustment by a logic level PWM signal. 1 2 • • • • • • • • • • Drives up to 2 strings of 10 series LEDs Up to 87% efficient 8-bit I2C-Compatible Programmable Exponential or Linear Brightness Control PWM Brightness Control for CABC Operation Independent Current Control per String True Shutdown Isolation for LEDs Internal Soft-Start Limits Inrush Current Wide 2.3V to 5.5V Input Voltage Range Adaptive Headroom Programmable 16V/24V/32V/40V Over-Voltage Protection Selectable Boost Frequency of 500 kHz or 1MHz with optionally additional offset Low Profile 12-Bump DSBGA Package Solution Size 32mm² The boost switching frequency is programmable at 500 kHz for low switching loss performance or 1MHz to allow the use of tiny low profile inductors. A setting for a 10% offset of these frequencies is available. Over-voltage protection is programmable at 16V, 24V, 32V, or 40V to accommodate a wide variety of LED configurations and Schottky Diode/Output Capacitor combinations. The device operates over the 2.3V to 5.5V operating voltage range and -40°C to +85°C ambient temperature range. The LM3630A is available in an ultra-small 12-bump DSBGA package. APPLICATIONS • • Smart-Phone LCD Backlighting LCD + Keypad Lighting TYPICAL APPLICATION CIRCUIT L VOUT up to 40V D1 VIN CIN COUT IN SW OVP SDA SCL AP INTN LM3630A LED1 HWEN LED2 PWM SEL GND 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2013, Texas Instruments Incorporated LM3630A SNVS974 – APRIL 2013 www.ti.com TYPICAL PCB LAYOUT Schottky (SOD-323 40V) COUT (603 1uF) 4mm Inductor (VLF302512MT) CIN (0402 2.2uF) 8mm Figure 1. Typical PCB Layout (2 x 10 LED Application) CONNECTION DIAGRAM Bottom View Top View SDA SCL SW SW SCL SDA HWEN INTN GND GND INTN HWEN PWM SEL IN IN SEL PWM OVP ILED2 ILED1 ILED1 ILED2 OVP Figure 2. Package Number YFQ12HNA AVAILABLE OPTIONS PART NUMBER PACKAGE MARKING LM3630ATME YM LM3630ATMX D6 (1) 2 (1) PACKAGE YFQ12HNA SUPPLIED AS 250 Units, Tape & Reel 3000 Units, Tape & Reel YM = Date Code. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 PIN DESCRIPTIONS Ball Name Description 2 A1 SDA Serial Data Connection for I C-Compatible Interface A2 SCL Serial Clock Connection for I2C-Compatible Interface A3 SW Inductor Connection, Diode Anode Connection, and Drain Connection for Internal NFET. Connect the inductor and diode as close as possible to SW to reduce inductance and capacitive coupling to nearby traces. B1 HWEN B2 INTN Interrupt output for fault status change. Open drain active low signal. Logic High Hardware Enable B3 GND Ground C1 PWM External PWM Brightness Control Input C2 SEL Selects I2C-compatible address. Ground selects 7-bit address 36h. VIN selects address 38h. C3 IN D1 OVP D2 ILED2 Input Terminal to Internal Current Sink #2. D3 ILED1 Input Terminal to Internal Current Sink #1. Input Voltage Connection. Connect a 2.3V to 5.5V supply to IN and bypass to GND with a 2.2 µF or greater ceramic capacitor. Output Voltage Sense Connection for Over Voltage Sensing. Connect OVP to the positive terminal of the output capacitor. This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 3 LM3630A SNVS974 – APRIL 2013 www.ti.com ABSOLUTE MAXIMUM RATINGS (1) (2) VALUE UNIT IN, HWEN, PWM, SCL, SDA, INTN, SEL to GND −0.3 to 6.0 SW, OVP, ILED1, ILED2 to GND −0.3 to 45 Continuous Power Dissipation (3) Internally Limited Maximum Junction Temperature 150 −45 to +150 Storage Temperature Range T(J-MAX) ESD Rating Operating Ratings Maximum Lead Temperature (Soldering) Vapor Phase (60 sec.) (4) 215 Maximum Lead Temperature (Soldering) Infrared (15 sec.) (4) 220 Human Body Model (5) V Charged Device Mod °C 2 kV 500 V (1) (2) VIN Input Voltage Range TA Operating Ambient Temperature Range (6) 2.3 to 5.5 V −40 to +85 °C Thermal Properties θJA (1) (2) (3) (4) (5) (6) (7) 4 Junction-to-Ambient Thermal Resistance, YFQ12 package (7) 78.1 °C/W Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltages are with respect to the potential at the GND pin. Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ = 140°C (typ.) and disengages at TJ = 125°C (typ.). For detailed soldering specifications and information, please refer to Texas Instruments Application Note 1112: DSBGA Wafer Level Chip Scale Package (AN-1112) The Human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. (MIL-STD-883 3015.7) . In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be derated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = 125ºC), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to ambient thermal resistance of the part/package in the application (θJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (θJA × PD-MAX). Junction-to-ambient thermal resistance is highly dependent on application and board layout. In applications where high maximum power dissipation exists, special care must be paid to thermal dissipation issues in board design. For more information, please refer to Texas Instruments Application Note 1112: DSBGA Wafer Level Chip Scale Package. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 ELECTRICAL CHARACTERISTICS (1) Limits in standard typeface are for TA = 25°C, and limits in boldface type apply over the full operating ambient temperature range (−40°C ≤ TA ≤ +85°C). Unless otherwise specified, VIN = 3.6V. Symbol Parameter Condition Min Typ Max Units 19 20 21 mA -1 0.5 1 % -2.5 0.5 2.5 ILED1, ILED2 Output Current Regulation 2.5V ≤ VIN ≤ 5.5V, Full Scale Current = 20 mA IMATCH ILED1 to ILED2 Current Matching (2) 2.5V ≤ VIN ≤ 5.5V, ILED = 10 mA, TA = +25°C ILED1 on A 2.5V ≤ VIN ≤ 5.5V, ILED = ILED2 on B 10 mA, 0°C ≤ TA ≤ +70°C VREG_CS Regulated Current Sink Headroom Voltage ILED = 5 mA 250 VHR Current Sink Minimum Headroom Voltage ILED = 95% of nominal, ILED = 20 mA 160 RDSON NMOS Switch On Resistance ISW = 100 mA 0.25 mV 480 NMOS Switch Current Limit ICL VOVP Output Over-Voltage Protection DMAX 800 960 1000 1200 960 1200 1440 ON Threshold, 2.3V ≤ VIN ≤ 5.5V, 24V option 23 24 25 ON Threshold, 2.3V ≤ VIN ≤ 5.5V, 40V option 39 41 44 2.5V ≤ VIN ≤ 5.5V 538 Quiescent Current into Device, Not Switching. VIN = 3.6V ISHDN Shutdown Current 2.3V ≤ VIN ≤ 5.5V 481 500 518 1077 1120 1163 1MHz shift = 0 962 1000 1038 Initialization Timing kHz 94 % ILED1 = ILED2 = 20mA, Feedback disabled. 350 µA HWEN = VIN, I2C Shutdown 1 4 HWEN = GND 1 4 Full Scale Current = 20 mA, BRT = 0x01, Exponential Mapping Mode +140 °C 15 Time period to wait from the assertion of HWEN or after Software Reset, before an I2C transaction will be ACK'ed. During this time period an I2C transaction will be NAK'ed µA 13 Hysteresis tWAIT V 582 1.12 MHz shift = 1 Thermal Shutdown TSD 560 500 kHz shift = 0 Maximum Duty Cycle Minimum LED Current in ILED1 or ILED2 mA 1 IQ ILED_MIN 720 800 560 kHz shift = 1 Switching Frequency Ω 640 2.5V ≤ VIN ≤ 5.5V Hysteresis fSW 600 240 1 ms Logic Inputs (PWM, HWEN, SEL, SCL, SDA) VIL Input Logic Low 0 0.4 VIH Input Logic High 1.2 VIN VOL Output Logic Low (SDA, INTN) fPWM PWM Input Frequency CIN Input Capacitance (1) (2) 2.3V ≤ VIN ≤ 5.5V 10 SDA 4.5 SCL 5.0 V 400 mV 80 kHz pF Min and Max limits are specified by design, test, or statistical analysis. Typical numbers are not ensured, but do represent the most likely norm. Unless otherwise specified, conditions for typical specifications are: VIN = 3.6V and TA = +25ºC. LED current sink matching between LED1 and LED2 is given by taking the difference between ILED1 and ILED2 and dividing by the average. This simplifies to (ILED1 − ILED2)/(ILED1 + ILED2) x 2 at ILED = 10 mA. ILED1 is driven by Bank A and ILED2 is driven by Bank B. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 5 LM3630A SNVS974 – APRIL 2013 www.ti.com ELECTRICAL CHARACTERISTICS (1) (continued) Limits in standard typeface are for TA = 25°C, and limits in boldface type apply over the full operating ambient temperature range (−40°C ≤ TA ≤ +85°C). Unless otherwise specified, VIN = 3.6V. Symbol Parameter Condition I2C-Compatible Timing Specifications (SCL, SDA) Min t1 SCL (Clock Period) 2.5 t2 Data in Setup Time to SCL High 100 t3 Data in Setup Time to SCL Low 0 t4 SDA Low Setup Time to SCL Low (Start) 100 t5 SDA High Hold Time to SCL High (Stop) 100 (3) Typ Max Units (3) µs ns SCL and SDA must be glitch-free in order for proper brightness to be realized. TYPICAL PERFORMANCE CHARACTERISTICS TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. Boost and LED Efficiency at VIN = 2.7V, 2p6s, Freq=500kHz, L=22uH 90 90 80 80 Efficiency % Efficiency % Boost and LED Efficiency at VIN = 2.5V, 2p6s, Freq=500kHz, L=22uH 70 60 50 VIN = 2.5V Freq = 500kHz LED = 2p6s L = 22uH Boost LED 70 60 50 Boost LED 40 40 0 20 40 60 80 Brightness % 100 0 20 40 60 80 Brightness % C001 100 C058 Figure 4. Boost and LED Efficiency at VIN = 3.6V, 2p6s, Freq=500kHz, L=22µH Boost and LED Efficiency at VIN = 4.2V, 2p6s, Freq=500kHz, L=22uH 90 90 80 80 Efficiency % Efficiency % Figure 3. 70 60 50 VIN = 3.6V Freq = 500kHz LED = 2p6s L = 22uH Boost LED 70 60 50 VIN = 4.2V Freq = 500kHz LED = 2p6s L = 22uH Boost LED 40 40 0 20 40 60 Brightness % 80 100 0 C059 Figure 5. 6 VIN = 2.7V Freq = 500kHz LED = 2p6s L = 22uH 20 40 60 Brightness % 80 100 C060 Figure 6. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. Boost and LED Efficiency at VIN = 2.5V, 2p6s, Freq=500kHz, L=10uH 90 90 80 80 Efficiency % Efficiency % Boost and LED Efficiency at VIN = 5.5V, 2p6s, Freq=500kHz, L=22uH 70 VIN = 5.5V Freq = 500kHz LED = 2p6s L = 22uH 60 50 70 60 50 Boost VIN = 2.5V Freq = 500kHz LED = 2p6s L = 10uH Boost LED LED 40 40 0 20 40 60 80 Brightness % 100 0 20 40 60 80 Brightness % C061 100 C003 Figure 8. Boost and LED Efficiency at VIN = 2.7V, 2p6s, Freq=500kHz, L=10uH Boost and LED Efficiency at VIN = 3.6V, 2p6s, Freq=500kHz, L=10uH 90 90 80 80 Efficiency % Efficiency % Figure 7. 70 60 50 VIN = 2.7V Freq = 500kHz LED = 2p6s L = 10uH Boost LED 70 60 50 VIN = 3.6V Freq = 500kHz LED = 2p6s L = 10uH Boost LED 40 40 0 20 40 60 80 Brightness % 100 0 20 40 60 80 Brightness % C004 100 C005 Figure 10. Boost and LED Efficiency at VIN = 4.2V, 2p6s, Freq=500kHz, L=10uH Boost and LED Efficiency at VIN = 5.5V, 2p6s, Freq=500kHz, L=10uH 90 90 80 80 Efficiency % Efficiency % Figure 9. 70 60 50 VIN = 4.2V Freq = 500kHz LED = 2p6s L = 10uH Boost LED 70 60 50 VIN = 5.5V Freq = 500kHz LED = 2p6s L = 10uH Boost LED 40 40 0 20 40 60 Brightness % 80 100 0 C006 Figure 11. 20 40 60 80 Brightness % 100 C007 Figure 12. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 7 LM3630A SNVS974 – APRIL 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. Boost and LED Efficiency at VIN = 2.7V, 1p10s, Freq=500kHz, L=22uH 90 90 80 80 Efficiency % Efficiency % Boost and LED Efficiency at VIN = 2.5V, 1p10s, Freq=500kHz, L=22uH 70 60 50 VIN = 2.5V Freq = 500kHz LED = 1p10s L = 22uH Boost LED 20 40 60 80 Boost LED 100 Brightness % 0 20 40 60 80 Brightness % C008 Figure 14. Boost and LED Efficiency at VIN = 3.6V, 1p10s, Freq=500kHz, L=22uH Boost and LED Efficiency at VIN = 4.2V, 1p10s, Freq=500kHz, L=22uH 90 80 80 Efficiency % 90 70 60 VIN = 3.6V Freq = 500kHz LED = 1p10s L = 22uH Boost LED 70 60 50 VIN = 4.2V Freq = 500kHz LED = 1p10s L = 22uH Boost LED 40 100 C009 Figure 13. 50 40 0 20 40 60 80 100 Brightness % 0 20 40 60 80 Brightness % C010 100 C011 Figure 15. Figure 16. Boost and LED Efficiency at VIN = 5.5V, 1p10s, Freq=500kHz, L=22uH Boost and LED Efficiency at VIN = 2.5V, 1p10s, Freq=500kHz, L=10uH 90 90 80 80 70 Efficiency % VIN = 5.5V Freq = 500kHz LED = 1p10s L = 22uH 60 50 70 60 50 Boost VIN = 2.5V Freq = 500kHz LED = 1p10s L = 10uH Boost LED LED 40 40 0 20 40 60 Brightness % 80 100 0 C012 Figure 17. 8 VIN = 2.7V Freq = 500kHz LED = 1p10s L = 22uH 40 0 Efficiency % 60 50 40 Efficiency % 70 20 40 60 Brightness % 80 100 C013 Figure 18. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. Boost and LED Efficiency at VIN = 3.6V, 1p10s, Freq=500kHz, L=10uH 90 90 80 80 Efficiency % Efficiency % Boost and LED Efficiency at VIN = 2.7V, 1p10s, Freq=500kHz, L=10uH 70 60 50 VIN = 2.7V Freq = 500kHz LED = 1p10s L = 10uH Boost LED 60 50 VIN = 3.6V Freq = 500kHz LED = 1p10s L = 10uH Boost LED 40 40 0 20 40 60 80 100 Brightness % 0 20 40 60 80 100 Brightness % C014 C015 Figure 19. Figure 20. Boost and LED Efficiency at VIN = 4.2V, 1p10s, Freq=500kHz, L=10uH Boost and LED Efficiency at VIN = 5.5V, 1p10s, Freq=500kHz, L=10uH 90 90 80 80 70 60 VIN = 4.2V Freq = 500kHz LED = 1p10s L = 10uH 50 Boost Efficiency % Efficiency % 70 70 VIN = 5.5V Freq = 500kHz LED = 1p10s L = 10uH 60 50 Boost LED LED 40 40 0 20 40 60 80 100 Brightness % 0 20 40 60 80 100 Brightness % C016 C017 Figure 22. Boost and LED Efficiency at VIN = 2.5V, 2p10s, Freq=1MHz, L=10uH Boost and LED Efficiency at VIN = 2.7V, 2p10s, Freq=1MHz, L=10uH 90 90 80 80 Efficiency % Efficiency % Figure 21. 70 60 VIN = 2.5V Freq = 1MHz LED = 2p10s L = 10uH 50 70 VIN = 2.7V Freq = 1MHz LED = 2p10s L = 10uH 60 50 Boost Boost LED LED 40 40 0 20 40 60 Brightness % 80 100 0 C018 Figure 23. 20 40 60 80 Brightness % 100 C019 Figure 24. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 9 LM3630A SNVS974 – APRIL 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. Boost and LED Efficiency at VIN = 4.2V, 2p10s, Freq=1MHz, L=10uH 90 90 80 80 Efficiency % Efficiency % Boost and LED Efficiency at VIN = 3.6V, 2p10s, Freq=1MHz, L=10uH 70 60 50 VIN = 3.6V Freq = 1MHz LED = 2p10s L = 10uH Boost LED 70 VIN = 4.2V Freq = 1MHz LED = 2p10s L = 10uH 60 50 Boost LED 40 40 0 20 40 60 80 100 Brightness % 0 40 60 80 Brightness % Boost and LED Efficiency at VIN = 5.5V, 2p10s, Freq=1MHz, L=10uH Boost and LED Efficiency at VIN = 2.7V, 2p10s, Freq=500kHz, L=10uH 90 80 80 70 Efficiency % Efficiency % Figure 26. 90 VIN = 5.5V Freq = 1MHz LED = 2p10s L = 10uH 60 70 60 50 Boost LED 40 0 20 40 60 80 Brightness % 100 0 20 40 60 80 Brightness % C022 Figure 28. Boost and LED Efficiency at VIN = 3.6V, 2p10s, Freq=500kHz, L=10uH Boost and LED Efficiency at VIN = 4.2V, 2p10s, Freq=500kHz, L=10uH 90 90 80 80 70 60 50 VIN = 3.6V Freq = 500kHz LED = 2p10s L = 10uH Boost LED 70 60 50 VIN = 4.2V Freq = 500kHz LED = 2p10s L = 10uH Boost LED 40 100 C023 Figure 27. Efficiency % Efficiency % VIN = 2.7V Freq = 500kHz LED = 2p10s L = 10uH Boost LED 40 100 C021 Figure 25. 50 40 0 20 40 60 Brightness % 80 100 0 C024 Figure 29. 10 20 C020 20 40 60 Brightness % 80 100 C025 Figure 30. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. Boost and LED Efficiency at VIN = 5.5V, 2p10s, Freq=500kHz, L=10uH IIN across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 3.0 90 2p6s, L=10uH,Freq=500kHz 2.5 2.0 70 IIN (mA) Efficiency % 80 VIN = 5.5V Freq = 500kHz LED = 2p10s L = 10uH 60 50 1.5 1.0 Boost 0.5 LED1 & 2 on DACA IIN vs VIN LED 40 2.7V 3.05V 3.6V 4.2V 5.5V 0.0 0 20 40 60 80 Brightness % 100 0 20 40 60 80 Brightness % C026 100 C029 Figure 32. PWR_IN across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA VOUT across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 17.0 2.7V 3.05V 3.6V 4.2V 5.5V 24 22 20 18 16 14 12 10 8 6 4 2 0 LED1 & 2 on DACA PWR_IN vs VIN 2.7V 3.05V 3.6V 4.2V 5.5V 16.5 16.0 2p6s, L=10uH,Freq=500kHz VOUT (V) PWR_IN (mW) Figure 31. 15.5 15.0 2p6s, L=10uH,Freq=500kHz 14.5 LED1 & 2 on DACA VOUT vs VIN 14.0 0 20 40 60 80 Brightness % 0 100 20 40 60 80 Brightness % C030 100 C003 Figure 33. Figure 34. IOUT across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA PWR_OUT across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 60 40 2.7V 3.05V 3.6V 4.2V 5.5V 900 800 PWR_OUT (mW) 50 IOUT (mA) 1000 2.7V 3.05V 3.6V 4.2V 5.5V 2p6s, L=10uH,Freq=500kHz 30 20 2p6s, L=10uH,Freq=500kHz 600 500 400 300 200 LED1 & 2 on DACA IOUT vs VIN 10 700 LED1 & 2 on DACA PWR_OUT vs VIN 100 0 0 0 20 40 60 Brightness % 80 100 0 C032 Figure 35. 20 40 60 80 Brightness % 100 C033 Figure 36. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 11 LM3630A SNVS974 – APRIL 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. ILED across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 30 2.7V 3.05V 3.6V 4.2V 5.5V 400 350 I_Inductor (mA) 20 ILED (mA) 450 2.7V 3.05V 3.6V 4.2V 5.5V 2p6s, L=10uH,Freq=500kHz 25 I_Inductor across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 15 10 300 2p6s,L=10uH,Freq=500kHz 250 200 150 100 LED1 & 2 on DACA ILED vs VIN 5 LED1 & 2 On DACA I_Inductor vs VIN 50 0 0 0 20 40 60 80 0 100 Brightness % 40 60 80 Brightness % 100 C035 Figure 37. Figure 38. IIN across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA PWR_IN across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 3.0 2p6s, L=10uH,Freq=500kHz 2.5 1.5 1.0 2.7V 3.05V 3.6V 4.2V 5.5V LED1 DACA LED2 DACB IIN vs VIN 0.5 0.0 0 20 40 60 80 Brightness % 2.7V 3.05V 3.6V 4.2V 5.5V 2p6s, L=10uH,Freq=500kHz 24 22 20 18 16 14 12 10 8 6 4 2 0 100 0 20 40 LED1 DACA LED2 DACB PWR_IN vs VIN 60 80 Brightness % C029 100 C030 Figure 39. Figure 40. VOUT across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA IOUT across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 17.0 60 2.7V 3.05V 3.6V 4.2V 5.5V 16.0 2.7V 3.05V 3.6V 4.2V 5.5V 50 2p6s, L=10uH,Freq=500kHz 40 15.5 IOUT (mA) 16.5 VOUT (V) PWR_IN (mW) IIN (mA) 2.0 2p6s, L=10uH,Freq=500kHz 15.0 30 20 LED1 DACA LED 2 DACB VOUT vs VIN 14.5 LED1 DACA LED2 DACB IOUT vs VIN 10 14.0 0 0 20 40 60 Brightness % 80 100 0 C003 Figure 41. 12 20 C034 20 40 60 Brightness % 80 100 C032 Figure 42. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. PWR_OUT across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 1200 30 2.7V 3.05V 3.6V 4.2V 5.5V 800 2.7V 3.05V 3.6V 4.2V 5.5V 25 20 ILED (mA) 1000 PWR_OUT (mW) ILED across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 2p6s, L=10uH,Freq=500kHz 600 400 2p6s, L=10uH,Freq=500kHz 15 10 LED1 DACA LED2 DACB PWR_OUT vs VIN 200 LED1 DACA LED2 DACB ILED vs VIN 5 0 0 0 20 40 60 80 Brightness % 100 0 20 40 60 80 100 Brightness % C033 C034 Figure 43. Figure 44. I_Inductor across VIN, 2p6s, Freq=500kHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA IIN across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 450 2.7V 3.05V 3.6V 4.2V 5.5V 400 300 4.0 3.5 2p6s,L=10uH,Freq=500kHz 250 2p10s, L=10uH,Freq=1MHz 4.5 LED1 DACA LED2 DACB I_Inductor vs VIN IIN (mA) I_Inductor (mA) 350 5.0 200 150 3.0 2.5 2.0 2.7V 3.05V 3.6V 4.2V 5.5V 1.5 100 1.0 50 0.5 0 LED1 & 2 on DACA IIN vs VIN 0.0 0 20 40 60 80 Brightness % 0 100 20 40 60 80 Brightness % C035 100 C029 Figure 46. PWR_IN across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA VOUT across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 28 2.7V 3.05V 3.6V 4.2V 5.5V 2.7V 3.05V 3.6V 4.2V 5.5V LED1 & 2 on DACA PWR_IN vs VIN 27 VOUT (V) PWR_IN (mW) Figure 45. 2p10s, L=10uH,Freq=1MHz 26 2p10s, L=10uH,Freq=1MHz 25 LED1 & 2 on DACA VOUT vs VIN 24 0 20 40 60 Brightness % 80 100 0 C030 Figure 47. 20 40 60 80 Brightness % 100 C003 Figure 48. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 13 LM3630A SNVS974 – APRIL 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. IOUT across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 60 2.7V 3.05V 3.6V 4.2V 5.5V 1600 1400 PWR_OUT (mW) 40 IOUT (mA) 1800 2.7V 3.05V 3.6V 4.2V 5.5V 50 PWR_OUT across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 2p10s, L=10uH,Freq=1MHz 30 20 1200 800 600 400 LED1 & 2 on DACA IOUT vs VIN 10 2p10s, L=10uH,Freq=1MHz 1000 LED1 & 2 on DACA PWR_OUT vs VIN 200 0 0 0 20 40 60 80 100 Brightness % 0 20 40 60 80 Brightness % C032 100 C033 Figure 49. Figure 50. ILED across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA I_Inductor across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 30 20 2.7V 3.05V 3.6V 4.2V 5.5V 800 700 I_Inductor (mA) 25 ILED (mA) 900 2.7V 3.05V 3.6V 4.2V 5.5V 2p10s, L=10uH,Freq=1MHz 15 10 600 2p10s,L=10uH,Freq=1MHz 500 400 300 200 LED1 & 2 on DACA ILED vs VIN 5 LED1 & 2 On DACA I_Inductor vs VIN 100 0 0 0 20 40 60 80 100 Brightness % 0 40 60 80 Brightness % 100 C035 Figure 51. Figure 52. IIN across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA PWR_IN across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 50 5.0 2p10s, L=10uH,Freq=1MHz 4.0 40 3.5 35 3.0 2.5 2.0 2.7V 3.05V 3.6V 4.2V 5.5V 1.5 LED1 DACA LED2 DACB IIN vs VIN 1.0 0.5 0.0 0 20 40 2.7V 3.05V 3.6V 4.2V 5.5V 45 PWR_IN (mW) IIN (mA) 4.5 60 Brightness % 80 LED1 DACA LED2 DACB PWR_IN vs VIN 2p10s, L=10uH,Freq=1MHz 30 25 20 15 10 5 0 100 0 C029 Figure 53. 14 20 C034 20 40 60 Brightness % 80 100 C030 Figure 54. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. VOUT across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 28 60 2.7V 3.05V 3.6V 4.2V 5.5V 2.7V 3.05V 3.6V 4.2V 5.5V 2p10s, L=10uH,Freq=1MHz 50 40 IOUT (mA) 27 VOUT (V) IOUT across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 26 2p10s, L=10uH,Freq=1MHz 30 20 25 LED1 DACA LED 2 DACB VOUT vs VIN LED1 DACA LED2 DACB IOUT vs VIN 10 24 0 0 20 40 60 80 Brightness % 100 0 20 40 60 80 100 Brightness % C003 C032 Figure 55. Figure 56. PWR_OUT across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA ILED across VIN, 2p10s, Freq=1MHz, L=10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 1800 1400 1200 20 2p10s, L=10uH,Freq=1MHz 1000 800 2p10s,L=10uH,Freq=1MHz 15 10 600 LED1 DACA LED2 DACB PWR_OUT vs VIN 400 200 LED1 DACA LED2 DACB ILED vs VIN 5 0 0 0 20 40 60 80 Brightness % 0 100 20 40 60 80 100 Brightness % C033 C034 Figure 57. Figure 58. I_Inductor across VIN, 2p10s, Freq=1MHz, L = 10uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA IIN across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 1000 2.7V 3.05V 3.6V 4.2V 5.5V 900 800 700 600 3.0 2p6s, L=22uH,Freq=500kHz LED1 DACA LED2 DACB I_Inductor vs VIN 2.5 2.0 2p10s,L=10uH,Freq=1MHz IIN (mA) I_Inductor (mA) 2.7V 3.05V 3.6V 4.2V 5.5V 25 ILED (mA) 1600 PWR_OUT (mW) 30 2.7V 3.05V 3.6V 4.2V 5.5V 500 400 1.5 1.0 300 200 0.5 LED1 & 2 on DACA IIN vs VIN 100 0 2.7V 3.05V 3.6V 4.2V 5.5V 0.0 0 20 40 60 Brightness % 80 100 0 C035 Figure 59. 20 40 60 80 Brightness % 100 C029 Figure 60. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 15 LM3630A SNVS974 – APRIL 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. 17.0 2.7V 3.05V 3.6V 4.2V 5.5V 24 22 20 18 16 14 12 10 8 6 4 2 0 VOUT across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA LED1 & 2 on DACA PWR_IN vs VIN 2.7V 3.05V 3.6V 4.2V 5.5V 16.5 16.0 2p6s, L=22uH,Freq=500kHz VOUT (V) PWR_IN (mW) PWR_IIN across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 15.5 2p6s, L=22uH,Freq=500kHz 15.0 14.5 LED1 & 2 on DACA VOUT vs VIN 14.0 0 20 40 60 80 Brightness % 0 100 40 60 80 Brightness % 100 C003 Figure 61. Figure 62. IOUT across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA PWR_IOUT across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 60 2.7V 3.05V 3.6V 4.2V 5.5V 1000 PWR_OUT (mW) 40 IOUT (mA) 1200 2.7V 3.05V 3.6V 4.2V 5.5V 50 2p6s, L=22uH,Freq=500kHz 30 20 LED1 & 2 on DACA IOUT vs VIN 10 800 2p6s, L=22uH,Freq=500kHz 600 400 LED1 & 2 on DACA PWR_OUT vs VIN 200 0 0 0 20 40 60 80 Brightness % 100 0 20 40 60 80 Brightness % C032 100 C033 Figure 63. Figure 64. ILED across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA I_Inductor across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 & 2 on DACA, ILED Full Scale=28.5mA 30 2.7V 3.05V 3.6V 4.2V 5.5V 450 400 I_Inductor (mA) 20 ILED (mA) 500 2.7V 3.05V 3.6V 4.2V 5.5V 25 2p6s,L=22uH,Freq=500kHz 15 10 350 300 2p6s,L=22uH,Freq=500kHz 250 200 150 100 LED1 & 2 on DACA ILED vs VIN 5 LED1 & 2 On DACA I_Inductor vs VIN 50 0 0 0 20 40 60 Brightness % 80 100 0 C034 Figure 65. 16 20 C030 20 40 60 Brightness % 80 100 C035 Figure 66. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. IIN across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA PWR_IIN across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 3.0 2.5 1.5 1.0 2.7V 3.05V 3.6V 4.2V 5.5V LED1 DACA LED2 DACB IIN vs VIN 0.5 0.0 0 20 40 60 80 Brightness % 100 0 40 60 80 Brightness % C029 100 C030 Figure 68. VOUT across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA IOUT across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 60 2.7V 3.05V 3.6V 4.2V 5.5V 16.0 2.7V 3.05V 3.6V 4.2V 5.5V 50 2p6s, L=22uH,Freq=500kHz 40 IOUT (mA) 16.5 15.5 2p6s, L=22uH,Freq=500kHz 15.0 30 20 LED1 DACA LED 2 DACB VOUT vs VIN 14.5 LED1 DACA LED2 DACB IOUT vs VIN 10 14.0 0 0 20 40 60 80 Brightness % 100 0 20 40 60 80 Brightness % C003 100 C032 Figure 69. Figure 70. PWR_OUT across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA ILED across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 1200 30 2.7V 3.05V 3.6V 4.2V 5.5V 800 2.7V 3.05V 3.6V 4.2V 5.5V 25 20 ILED (mA) 1000 PWR_OUT (mW) 20 LED1 DACA LED2 DACB PWR_IN vs VIN Figure 67. 17.0 VOUT (V) PWR_IN (mW) IIN (mA) 2.0 2.7V 3.05V 3.6V 4.2V 5.5V 2p6s, L=22uH,Freq=500kHz 24 22 20 18 16 14 12 10 8 6 4 2 0 2p6s, L=22uH,Freq=500kHz 2p6s, L=22uH,Freq=500kHz 600 400 2p6s, L=22uH,Freq=500kHz 15 10 LED1 DACA LED2 DACB PWR_OUT vs VIN 200 LED1 DACA LED2 DACB ILED vs VIN 5 0 0 0 20 40 60 Brightness % 80 100 0 C033 Figure 71. 20 40 60 80 Brightness % 100 C034 Figure 72. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 17 LM3630A SNVS974 – APRIL 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) TA = +25°C, ILED Full Scale = 20.0mA unless specified otherwise. I_Inductor across VIN, 2p6s, Freq=500kHz, L=22uH, LED1 on DACA, LED2 on DACB, ILED Full Scale=28.5mA 500 2.7V 3.05V 3.6V 4.2V 5.5V 450 I_Inductor (mA) 400 350 300 LED1 DACA LED2 DACB I_Inductor vs VIN 2p6s,L=22uH,Freq=500kHz 250 200 150 100 50 0 0 20 40 60 Brightness % 80 100 C035 Figure 73. 18 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 FUNCTIONAL DESCRIPTION VIN CIN COUT SW HWEN Global Enable/ Disable Reference and Thermal Shutdown OVP Programmable Over Voltage Protection (16V, 24V, 32V, 40V) Boost Converter 1A Current Limit Current Sinks Programmable 500 kHz/1 Mhz Switching Frequency LED1 LED String Open/ Short Detection LED2 Backlight LED Control PWM PWM Sampler 1. 5-bit Full Scale Current Select 2. 8-bit brightness adjustment 3. Linear/Exponential Dimming SDA SCL 2 I CCompatible Interface 4. LED Current Ramping Fault Detection OVP OCP TSD INTN SEL Operation The LM3630A provides the power for two high-voltage LED strings (up to 40V at 28.5 mA each). The two highvoltage LED strings are powered from an integrated asynchronous boost converter. The device is programmable over an I2C-compatible interface. Additional features include a PWM input for content adjustable brightness control, programmable switching frequency, and programmable over voltage protection (OVP). Control Bank Mapping Control of the LM3630A’s current sinks is not done directly, but through the programming of Control Banks. The current sinks are then assigned to the programmed Control Bank (see Figure 74). Both current sinks can be assigned to Control Bank A or LED1 can use Control Bank A while LED2 uses Control Bank B. Assigning LED1 to Control Bank A and LED2 to Control Bank B allows for better LED current matching. Assigning each current sink to different control banks allows for each current sink to be programmed with a different current or have the PWM input control a specific current sink. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 19 LM3630A SNVS974 – APRIL 2013 www.ti.com Current Sinks Control Banks Internal PWM Filter PWM Input (Assigned to Control Banks) LED1 BANK A LE D2 PWM Input PWM _O N_ A =1 LED2 BANK B LED2_ON_A = 0 Figure 74. Control Diagram Table 1. Bank Configuration Examples-Register Values (1) Registers to Program ILED1 on A, ILED2 on B with PWM Dimming (1) ILED1 and ILED2 on A with PWM Dimming ILED1 on A with PWM ILED2 on B no PWM Control 1EH linear or 06h exp 15h linear or 05h exp 1EH linear or 06h exp Configuration 1Bh 09h 19h Brightness A used for A used for both used for A Brightness B used for B not used used for B (A and B do not have to be equal) LED current matching is specified using this configuration. PWM Input Polaritiy The PWM Input can be set for active high (default) or active low polarity. With active low polarity the LED current is a function of the negative duty cycle at PWM. HWEN Input HWEN is the global hardware enable to the LM3630A. HWEN must be pulled high to enable the device. HWEN is a high-impedance input so it cannot be left floating. When HWEN is pulled low the LM3630A is placed in shutdown and all the registers are reset to their default state. SEL Input SEL is the select pin for the serial bus device address. When this pin is connected to ground, the seven-bit device address is 36H. When this pin is tied to the VIN power rail, the device address is 38H. INTN Output The INTN pin is an open drain active low output signal which will indicate detected faults. The signal will assert low when either OCP, OVP, or TSD is detected by the LED driver. The Interrupt Enable register must be set to connect these faults to the INTN pin. 20 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 Boost Converter The high-voltage boost converter provides power for the two current sinks (ILED1 and ILED2). The boost circuit operates using a 10 μH to 22 μH inductor and a 1μF output capacitor. The selectable 500 kHz or 1MHz switching frequency allows for the use of small external components and provides for high boost converter efficiency. Both LED1 and LED2 feature an adaptive voltage regulation scheme where the feedback point (LED1 or LED2) is regulated to a minimum of 300 mV. When there are different voltage requirements in both high-voltage LED strings, because of different programmed voltages or string mismatch, the LM3630A will regulate the feedback point of the highest voltage string to 300 mV and drop the excess voltage of the lower voltage string across the lower strings current sink. Boost Switching Frequency Select The LM3630A’s boost converter can have a 1MHz or 500 kHz switching frequency. For a 500 kHz switching frequency the inductor must be between 10 μH and 22 μH. For the 1MHz switching frequency the inductor can be between 10 μH and 22 μH. Additionally there is a Frequency Shift bit which will offset the frequency approximately 10%. For the 500 kHz setting, Shift = 0. The boost frequency is shifted to 560 kHz when Shift = 1. For the 1MHz setting, Shift = 0. The boost frequency is shifted to 1120 kHz when Shift = 1. Adaptive Headroom Reference Figure 75 and Figure 76 for the following description. The adaptive headroom circuit controls the Boost output voltage to provide the minimal headroom voltage necessary for the current sinks to provide the specified ILED current. The headroom voltage is fed back to the Error Amplifier to dynamically adjust the Boost output voltage. The Error Amplifier's reference voltage is adjusted as the brightness level is changed, since the currents sinks require less headroom at lower ILED currents than at higher ILED currents. Note that the VHR Min block dynamically selects the LED string that requires the higher Boost voltage to maintain the ILED current, this string will have the lower headroom voltage. In Figure 76 this is LED string 2. The headroom voltage on LED string 1 is higher, but this is due to LED string 2 have an overall higher forward voltage than LED string 1. LED strings that have closely matched forward voltages will have closely matched headroom voltages and better overall efficiency. In a single string LED configuration the Feedback enable must be enabled for only that string (LED1 or LED2). The adaptive headroom circuit is control by that single string. In a two string LED configuration the Feedback enable must be enabled for both strings (LED1 and LED2). The VHR Min block then dynamically selects the LED string to control the adaptive headroom circuit. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 21 LM3630A SNVS974 – APRIL 2013 www.ti.com VIN SW COUT OVP Headroom Control Boost Controller + IIN Error Amplifier CIN Brightness Control LED1 VHR Min LED2 Feedback Enable GND Figure 75. Adaptive Headroom Block Diagram 0.35 VHR1 Headroom Voltage (V) VHR2 0.30 0.25 0.20 0 20 40 60 Brightness % 80 100 C001 Figure 76. Typical Headroom Voltage Curves 22 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 Current Sinks LED1 and LED2 control the current up to a 40V LED string voltage. Each current sink has 5-bit full-scale current programmability and 8-bit brightness control. Either current sink has its current set through a dedicated brightness register and can additionally be controlled via the PWM input. Current String Biasing Each current string can be powered from the LM3630A’s boost or from an external source. When powered from an external source the feedback input for either current sink can be disabled in the Configuration register so it no longer controls the boost output voltage. Full-Scale LED Current The LM3630A’s full-scale current is programmable with 32 different full scale levels. The full-scale current is the LED current in the control bank when the brightness code is at max code (0xFF). The 5 bit full-scale current vs code is given by the following equation: ILED FULLSCALE = 5 mA + Code x 0.75 mA (1) With a maximum full-scale current of 28.5 mA. Brightness Register Each control bank has its own 8-bit brightness register. The brightness register code and the full-scale current setting determine the LED current depending on the programmed mapping mode. Exponential Mapping In exponential mapping mode the brightness code to backlight current transfer function is given by the equation: §Code +1·º ª «44 - ¨5.81818¸» © ¹¼ ILED = ILED_ FULLSCALE x 0.85 ¬ x DPWM (2) Where ILED_FULLSCALE is the full-scale LED current setting, Code is the backlight code in the brightness register, and DPWM is the PWM input duty cycle. Figure 77 and Figure 78 show the approximate backlight code to LED current response using exponential mapping mode. Figure 77 shows the response with a linear Y axis, and Figure 78 shows the response with a logarithmic Y axis. In exponential mapping mode the current ramp (either up or down) appears to the human eye as a more uniform transition then the linear ramp. This is due to the logarithmic response of the eye. LED CURRENT (% of Full Scale) 100 90 80 70 60 50 40 30 20 10 0 0 51 102 153 204 255 BACKLIGHT CODE (D) Figure 77. Exponential Mapping Mode (Linear Scale) Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 23 LM3630A SNVS974 – APRIL 2013 www.ti.com LED CURRENT (% of Full Scale) 100 10 1 0.1 0 51 102 153 204 255 BACKLIGHT CODE (D) Figure 78. Exponential Mapping Mode (Log Scale) Linear Mapping In linear mapping mode the brightness code to backlight current has a linear relationship and follows the equation: ILED = ILED_ FULLSCALE x 1 x Code x DPWM 255 (3) Where ILED_FULLSCALE is the full scale LED current setting, Code is the backlight code in the brightness register, and DPWM is the PWM input duty cycle. Figure 79 shows the backlight code to LED current response using linear mapping mode. The Configuration register must be set to enable linear mapping. 100 LED CURRENT (% Full Scale) 90 80 70 60 50 40 30 20 10 0 0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 256 BACKLIGHT CODE (D) Figure 79. Linear Mapping Mode LED Current Ramping Startup/Shutdown Ramp The LED current turn on time from 0 to the initial LED current set-point is programmable. Similarly, the LED current shutdown time to 0 is programmable. Both the startup and shutdown times are independently programmable with 8 different levels. The Startup times are independently programmable from the Shutdown times, but not independently programmable for each Control bank. For example, programming a Start-up or Shutdown time, programs the same ramp time for each Control Bank. The Startup time is used when the device is first enabled to a non-zero brightness value. The Shutdown time is used when the brightness value is programmed to zero. If HWEN is used to disable the device, the action is immediate and the Shutdown time is not used. The zero code does take a small amount of time which is approximately 0.5 ms. Table 2. Startup/Shutdown Times 24 Code Startup Time Shutdown Time 000 4 ms 0 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 Table 2. Startup/Shutdown Times (continued) Code Startup Time Shutdown Time 001 261 ms 261 ms 010 522 ms 522 ms 011 1.045s 1.045s 100 2.091s 2.091s 101 4.182s 4.182s 110 8.364s 8.364s 111 16.73s 16.73s Run-Time Ramp Current ramping from one brightness level to the next is programmable. There are 8 different ramp up times and 8 different ramp down times. The ramp up time is independently programmable from the ramp down time, but not independently programmable for each Control Bank. For example, programming a ramp up time or a ramp down time will program the same ramp time for each control bank. The run time ramps are used whenever the device is enabled with a non-zero brightness value and a new non-zero brightness value is written. Table 3. LED Current Run Ramp Times Code Ramp-Up Time Ramp-Down Time 000 0 0 001 261 ms 261 ms 010 522 ms 522 ms 011 1.045s 1.045s 100 2.091s 2.091s 101 4.182s 4.182s 110 8.364s 8.364s 111 16.73s 16.73s Test Features The LM3630A contains an LED open, an LED short, and Over Voltage manufacturing fault detection. This fault detection is designed to be used during the manufacturing process only and not normal operation. These faults do not set the INTN pin. Open LED String (LED1 and LED2) An open LED string is detected when the voltage at the input to either LED1 or LED2 has fallen below 200 mV and the boost output voltage has hit the OVP threshold. This test assumes that the LED string that is being detected for an open is being powered from the boost output (Feedback Enabled). For an LED string not connected to the boost output, and connected to another voltage source, the boost output would not trigger the OVP flag. In this case an open LED string would not be detected. Shorted LED String The LM3630A features an LED short fault flag indicating if either of the LED strings have experienced a short. There are two methods that can trigger a short in the LED strings 1. An LED current sink with feedback enabled and the difference between OVP input and the LED current sink input voltage goes below 1V. 2. An LED current sink is configured with feedback disabled (not powered from the boost output) and the difference between VIN and the LED current sink input voltage goes below 1V. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 25 LM3630A SNVS974 – APRIL 2013 www.ti.com Over-Voltage Protection (Manufacturing Fault Detection and Shutdown) The LM3630A provides an Over-Voltage Protection (OVP) mechanism specifically for manufacturing test where a display may not be connected to the device. The over voltage protection threshold (OVP) on the LM3630A has 4 different programmable options (16V, 24V, 32V, and 40V). The manufacturing protection is enabled in the Fault Status register bit 0. When enabled, this feature will cause the boost converter to shutdown anytime the selected OVP threshold is exceeded. The OVP_fault bit in the Fault Status register will be set to one. The boost converter will not resume operation until the LM3630A is reset with either a write to the Software Reset bit in the Software Reset register or a cycling of the HWEN pin. The reset will clear the fault. Fault Flags/Protection Features The Interrupt Status register contains the status of the protection circuits of the LM3630A. The corresponding bits will be set to one if an OVP, OCP, or TSD event occurs. These faults do set the INTN pin when the corresponding bit is set in the Interrupt Enable register. Over-Voltage Protection (Inductive Boost Operation) The over-voltage protection threshold (OVP) on the LM3630A has 4 different programmable options (16V, 24V, 32V, and 40V). Over voltage protection protects the device and associated circuitry from high voltages in the event the feedback enabled LED string becomes open. During normal operation, the LM3630A’s inductive boost converter will boost the output up so as to maintain at least 300 mV at the active current sink inputs. When a high-voltage LED string becomes open the feedback mechanism is broken, and the boost converter will inadvertently over boost the output. When the output voltage reaches the over voltage protection (OVP) threshold the boost converter will stop switching, thus allowing the output node to discharge. When the output discharges to VOVP – 1V the boost converter will begin switching again. The OVP sense is at the OVP pin, so this pin must be connected directly to the inductive boost output capacitor’s positive terminal. For current sinks that have feedback disabled the over voltage sense mechanism is not in place to protect from potential over-voltage conditions. In this situation the application must ensure that the voltage at LED1 or LED2 doesn’t exceed 40V. The default setting for OVP is set at 24V. For applications that require higher than 24V at the boost output the OVP threshold will have to be programmed to a higher level at power up. Current Limit The switch current limit for the LM3630A’s inductive boost is set at 1A. When the current through the NFET switch hits this over current protection threshold (OCP) the device turns the NFET off and the inductor’s energy is discharged into the output capacitor. Switching is then resumed at the next cycle. The current limit protection circuitry can operate continuously each switch cycle. The result is that during high output power conditions the device can continuously run in current limit. Under these conditions the LM3630A’s inductive boost converter stops regulating the headroom voltage across the high voltage current sinks. This results in a drop in the LED current. Thermal Shutdown The LM3630A contains thermal shutdown protection. In the event the die temperature reaches +140°C, the boost power supply and current sinks will shut down until the die temperature drops to typically +125°C. Initialization Timing Initialization Timing with HWEN tied to VIN If the HWEN input is tied to VIN, then the tWAIT time starts when VIN crosses 2.5V as shown below. The initial I2C transaction can occur after the tWAIT time expires. Any I2C transaction during the tWAIT period will be NAK'ed. 26 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 2.5V twait = 1 ms VIN HWEN SCL SDA Figure 80. Initialization Timing with HWEN is tied to VIN Initialization Timing with HWEN driven by GPIO If the HWEN input is driven by a GPIO then the tWAITtime starts when HWEW crosses 1.2V as shown below. The initial I2C transaction can occur after the tWAIT time expires. Any I2C transaction during the tWAIT period will be NAK'ed VIN twait = 1 ms 1.2V HWEN SCL SDA Figure 81. Initialization Timing with HWEN driven by a GPIO Initialization after Software Reset The time between the I2C transaction that issues the software reset, and the subsequent I2C transaction (ie to configure the LM3630A) must be at greater or equal to the tWAIT period of 1ms. Any I2C transaction during the tWAIT period will be NAK'ed Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 27 LM3630A SNVS974 – APRIL 2013 www.ti.com I2C-COMPATIBLE INTERFACE Data Validity The data on SDA line must be stable during the HIGH period of the clock signal (SCL). In other words, state of the data line can only be changed when SCL is LOW. SCL SDA data change allowed data valid data change allowed data valid data change allowed Figure 82. Data Validity Diagram A pull-up resistor between the controller's VIO line, and SDA must be greater than [(VIO-VOL) / 3mA] to meet the VOL requirement on SDA. Using a larger pull-up resistor results in lower switching current with slower edges, while using a smaller pull-up results in higher switching currents with faster edges. Start And Stop Conditions START and STOP conditions classify the beginning and the end of the I2C session. A START condition is defined as SDA signal transitioning from HIGH to LOW while SCL line is HIGH. A STOP condition is defined as the SDA transitioning from LOW to HIGH while SCL is HIGH. The I2C master always generates START and STOP conditions. The I2C bus is considered to be busy after a START condition and free after a STOP condition. During data transmission, the I2C master can generate repeated START conditions. First START and repeated START conditions are equivalent, function-wise. SDA SCL S P START condition STOP condition Figure 83. Start and Stop Conditions Transfering Data Every byte put on the SDA line must be eight bits long, with the most significant bit (MSB) transferred first. Each byte of data has to be followed by an acknowledge bit. The acknowledge related clock pulse is generated by the master. The master releases the SDA line (HIGH) during the acknowledge clock pulse. The LM3630A pulls down the SDA line during the 9th clock pulse, signifying an acknowledge. The LM3630A generates an acknowledge after each byte is received. After the START condition, the I2C master sends a chip address. This address is seven bits long followed by an eighth bit which is a data direction bit (R/W). The LM3630A address is 36h. For the eighth bit, a “0” indicates a WRITE and a “1” indicates a READ. The second byte selects the register to which the data will be written. The third byte contains data to write to the selected register. I2C Compatible Address MSB 0 Bit 7 LSB 1 Bit 6 1 Bit 5 0 Bit 4 1 Bit 3 1 Bit 2 0 Bit 1 R/W Bit 0 Figure 84. I2C-Compatible Chip Address (0x36), SEL = 0 28 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 I2C Compatible Address MSB 0 Bit 7 LSB 1 Bit 6 1 Bit 5 1 Bit 4 0 Bit 3 0 Bit 2 0 Bit 1 R/W Bit 0 Figure 85. I2C-Compatible Chip Address (0x38), SEL = 1 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 29 LM3630A SNVS974 – APRIL 2013 www.ti.com LM3630A I2C Register Map This table summarizes LM3630A I2C-compatible register usage and shows default register bit values after reset, as programmed by the factory. The following sub-sections provide additional details on the use of individual registers. Register bits which are blank in the following tables are considered undefined. Undefined bits should be ignored on reads and written as zero. Slave Address [0x36h for SEL = 0, 0x38h for SEL = 1] Base Registers Register Name Address Type Default Reset Values Control 0x00 R/W 0xC0 Configuration 0x01 R/W 0x18 Boost Control 0x02 R/W 0x38 Brightness A 0x03 R/W 0x00 Brightness B 0x04 R/W 0x00 Current A 0x05 R/W 0x1F Current B 0x06 R/W 0x1F On/Off Ramp 0x07 R/W 0x00 Run Ramp 0x08 R/W 0x00 Interrupt Status 0x09 R/W 0x00 Interrupt Enable 0x0A R/W 0x00 Fault Status 0x0B R/W 0x00 Software Reset 0x0F R/W 0x00 PWM Out Low 0x12 Read 0x00 PWM Out High 0x13 Read 0x00 Revision 0x1F Read 0x02 Filter Strength 0x50 R/W 0x00 Register Descriptions Control (Offset = 0x00, Default = 0xC0) Register Bits 7 6 SLEEP_CMD SLEEP_ STATUS 5 4 3 2 1 0 LINEAR_A LINEAR_B LED_A_EN LED_B_EN LED2_ON_A Name Bit Access SLEEP_CMD 7 R/W Description The device is put into sleep mode when set to '1' SLEEP_STATUS 6 Read Reflects the sleep mode status. A '1' indicates the part is in sleep mode. Used to determine when part has entered or exited sleep mode after writing the SLEEP_CMD bit. 30 5 Read LINEAR_A 4 R/W Enables the linear output mode for Bank A when set to '1'. LINEAR_B 3 R/W Enables the linear output mode for Bank B when set to '1'. LED_EN_A 2 R/W Enables the LED A output LED_EN_B 1 R/W Enables the LED B output LED2_ON_A 0 R/W Connect the LED2 output to Bank A Control Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 Configuration (Offset = 0x01, Default = 0x18) Register Bits 7 Name 6 5 4 3 2 1 0 FB_EN_B FB_EN_A PWM_LOW PWM_EN-B PWM_EN_A Bit Access Description 7 Read 6 Read 5 Read FB_EN_B 4 R/W Enable Feedback on Bank B FB_EN_A 3 R/W Enable Feedback on Bank A PWM_LOW 2 R/W Sets the PWM to active low PWM_EN_B 1 R/W Enables the PWM for Bank B PWM_EN_A 0 R/W Enables the PWM for Bank A Boost Control (Offset = 0x02, Default = 0x38) Register Bits 7 6 5 4 3 2 BOOST_OVP[1] BOOST_OVP[0] BOOST_OCP[1] BOOST_OCP[0] SLOW_STAR T Name 1 0 SHIFT FMODE Bit Access 7 Read Description BOOST_OVP 6:5 R/W Selects the voltage limit for over-voltage protection: 00 = 16V 01 = 24V 10 = 32V 11 = 40V BOOST_OCP 4:3 R/W Selects the current limit for over-current protection: 00 = 600 mA 01 = 800 mA 10 = 1.0A 11 = 1.2A SLOW_START 2 R/W Slows the boost output transition SHIFT 1 R/W Enables the alternate oscillator frequencies: For FMODE = 0: SHIFT = 0F = 500 kHz; SHIFT 1F = 560 kHz For FMODE = 1: SHIFT = 0F = 1 MHz; SHIFT 1F = 1120 MHz FMODE 0 R/W Selects the boost frequency: 0 = 500 kHz, 1 = 1MHz Brightness A (Offset = 0x03, Default = 0x00) (1) Register Bits (1) 7 6 5 4 3 2 1 0 A[7] A[6] A[5] A[4] A[3] A[2] A[1] A[0] Name Bit Access A [7:0] R/W Description Sets the 8-bit brightness value for outputs connected to Bank A. Minimum brightness setting is code 04h. These registers will not update if the device is in Sleep Mode (Control: SLEEP_STATUS = 1). Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 31 LM3630A SNVS974 – APRIL 2013 www.ti.com Brightness B (Offset = 0x04, Default = 0x00) (1) Register Bits (1) 7 6 5 4 3 2 1 0 B[7] B[6] B[5] B[4] B[3] B[2] B[1] B[0] Name Bit Access B [7:0] R/W Description Sets the 8-bit brightness value for outputs connected to Bank B. Minimum brightness setting is code 04h. These registers will not update if the device is in Sleep Mode (Control: SLEEP_STATUS = 1). Current A (Offset = 0x05, Default 0x1F) Register Bits 7 6 Hysteresis Lower Bound 5 4 3 2 1 0 A[4] A[3] A[2] A[1] A[0] Name Bit Access Hysteresis 7 R/W Determines the hysteresis of the PWM Sampler. Clearing this bit, the PWM sampler changes its output upon detecting at least 3 equivalent code changes on the PWM input. Setting this bit, the PWM sampler changes its output upon detecting 2 equivalent code changes on the PWM input. Lower Bound 6 R/W Determines the lower bound of the PWM Sampler. Clearing this bit, the PWM sampler outputs code 6 when it detects equivalent codes 2 thru 6; and code 0 when it detects equivalent codes 0 thru 1. Setting this bit, the PWM sampler can output codes below 6, based upon the Hysteresis setting and equivalent code sampled from the input PWM. 5 Read [4:0] R/W A Description Sets the 5-bit full-scale current for outputs connected to Bank A. Current B (Offset = 0x06, Default = 0x1F) Register Bits 7 6 5 Name Bit Access B [4:0] R/W 4 3 2 1 0 B[4] B[3] B[2] B[1] B[0] Description Sets the 5-bit full-scale current for outputs connected to Bank B On/Off Ramp (Offset = 0x07, Default 0x00) Register Bits 7 Name 32 6 5 4 3 2 1 0 T_START[2] T_START[1] T_START[0] T_SHUT[2] T_SHUT[1] T_SHUT[0] Bit Access Description 7 Read 6 Read T_START [5:3] R/W Ramp time for startup events. T_SHUT [2:0] R/W Ramp time for shutdown events. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 Code Start-Up Time 000 4 ms Shutdown Time 0* 001 261 ms 261 ms 010 522 ms 522 ms 011 1.045s 1.045s 100 2.091s 2.091s 101 4.182s 4.182s 110 8.364s 8.364s 111 16.73s 16.73s *Code 0 results in approximately 0.5 ms ramp time. Run Ramp (Offset = 0x08, Default = 0x00) Register Bits 7 6 Name 5 4 3 2 1 0 T_UP[2] T_UP[1] T_UP[0] T_DOWN[2] T_DOWN[1] T_DOWN[0] Bit Access 7 Read Description 6 Read T_UP [5:3] R/W Time for ramp-up events T_DOWN [2:0] R/W Time for ramp-down events Code Ramp-Up Time Ramp-down Time 000 0* 0* 001 261 ms 261 ms 010 522 ms 522 ms 011 1.045s 1.045s 100 2.091s 2.091s 101 4.182s 4.182s 110 8.364s 8.364s 111 16.73s 16.73s *Code 0 results in approximately 0.5 ms ramp time. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 33 LM3630A SNVS974 – APRIL 2013 www.ti.com Interrupt Status (Offset = 0x09, Default = 0x00) Register Bits 7 Name 6 5 4 3 Bit Access 7 Read 6 Read 5 Read 4 Read 3 Read OCP 2 R/W An over-current condition occurred. OVP 1 R/W An over-voltage condition occurred. TSD 0 R/W A thermal shutdown event occurred. 2 1 0 OCP OVP TSD Description The interrupt status register is cleared upon a read of the register. If the condition that caused the interrupt is still present, then the bit will be set to one again and another interrupt is signaled on the INTN output pin. The interrupt status register is not cleared if the device is in sleep mode (Control: SLEEP_STATUS = 1). To disconnect the interrupt condition from the INTN pin during sleep mode, disable the fault connection in the Interrupt Enable register. An interrupt condition will set the status bit and cause an event on the INTN pin only if the corresponding bit in the Interrupt Enable register is one and the Global Enable bit is also one. Interrupt Enable (Offset = 0x0A, Default = 0x00) Register Bits 7 6 5 4 3 2 1 0 OCP OVP TSD Name Bit Access GLOBAL 7 R/W Description 6 Read 5 Read 4 Read 3 Read OCP 2 R/W Set to '1' to enable the over-current condition interrupt. OVP 1 R/W Set to '1' to enable the over-voltage condition interrupt. TSD 0 R/W Set to '1' to enable the thermal shutdown interrupt. Set to '1' to enable interrupts to drive the INTN pin. Fault Status (Offset = 0x0B, Default = 0x00) Register Bits 7 Name 6 5 4 3 2 1 0 OPEN LED2_SHORT LED1_SHORT SHORT_EN OVP_FAULT OVP_F_EN Bit Access 7 Read 6 Read Description . OPEN 5 R/W An open circuit was detected on one of the LED strings. LED2_SHORT 4 R/W A short was detected on LED string 2. LED1_SHORT 3 R/W A short was detected on LED string 1. SHORT_EN 2 R/W Set to '1' to enable short test. OVP_FAULT 1 R/W An OVP occurred in manufacturing test. OVP_F_EN 0 R/W Set to '1' to enable OVP manufacturing test. 34 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 Software Reset (Offset = 0x0F, Default = 0x00) Register Bits 7 6 5 4 3 2 1 0 SW_RESET Name SW_RESET Bit Access 7 Read 6 Read 5 Read 4 Read 3 Read 2 Read 1 Read 0 R/W Description . Set to '1' to reset the device. This is a full reset which clears the registers, executes a power-on reset, and reads the EPROM configuration. PWM Out Low (Offset = 0x12, Default 0x00) Register Bits 7 6 5 4 3 2 1 0 PWM_OUT[7] PWM_OUT[6] PWM_OUT[5] PWM_OUT[4] PWM_OUT[3] PWM_OUT[2] PWM_OUT[1] PWM_OUT[0] 2 1 PWM Out High (Offset = 0x13, Default 0x00) Register Bits 7 6 5 4 3 0 PWM_OUT[8] Name Bit Access PWM_OUT [7:0] R/W Description The value of the PWM detector. Maximum value is 256 or 100h. If PWM_OUT[7:0] is non-zero PWM_OUT[8] will be zero. Revision (Offset = 0x1F, Default = 0x02) Register Bits 7 6 5 4 3 2 1 0 REV[7] REV[6] REV[5] REV[4] REV[3] REV[2] REV[1] REV[0] Name Bit Access Description REV [7:0] R/W Revision value Filter Strength (Offset = 0x50, Default = 0x00) Register Bits 7 6 5 Name Bit Access FLTR_STR [1:0] R/W 4 3 2 1 0 FLTR_STR[1] FLTR_STR[0] Description Filter Strength Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 35 LM3630A SNVS974 – APRIL 2013 www.ti.com APPLICATION INFORMATION Recommended Initialization Sequence The recommended initialization sequence for the device registers is listed below. 1. Set Filter Strength register (offset=50h) to 03h. 2. Set Configuration register (offset=01h) to enable the PWM and the feedback for Bank A, For example writing 09h to the Configuration register, enables PWM and feedback for Bank A. Note the Bank B PWM and feedback need to be configured if Bank B is used, otherwise disable the Bank B feedback by clearing bit 4 and disable the Bank B PWM by clearing bit 1. 3. Configure the Boost Control register (offset=02h) to select the OVP, OCP and FMODE. For example writing 78h to the Boost Control register sets OVP to 40V, OCP to 1.2A and FMODE to 500 kHz. 4. Set the full scale LED current for Bank A and Bank B(if used), by writing to the Current A (offset=05h), and Current B(offset=06) registers. For example writing 14h to the Current A register selects a full scale LED current of 20 mA for Bank A. 5. Set the PWM Sampler Hysteresis to 2 codes by setting Bit 7 of the Current A register. Set the PWM Sampler Lower Bound code to 6 by clearing Bit 6 of the Current A register. Note these settings apply to both Bank A and Bank B. If only Bank B is used, these setting are still necessary when PWM is enabled. 6. Select the current control and enable or disable the LED Bank A and/or B by writing to Control register(offset=00h). For example writing 14h to the Control register select linear current control and enables Bank A. 7. Set the LED brightness by writing to Brightness A (Offset=03h) and Brightness B(Offset=04h) registers. For example writing FFh to Brightness A will set the LED current to 20 mA, with the Current A register set to 14h and the PWM input is high. PWM Operation Current Scaling 2 MHz clock Filter Strength PWM Input Sample Period LPF ILED Brightness R3 & R4 Hysteresis Min PWM value Full Scale R5 & R6 Figure 86. PWM Sampler 36 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 Hysteresis Block Output Previous Previous Value No LPF Output Sampled Value Yes Sampled > Previous +2? or Sampled < Previous Output Sample Figure 87. Hysteresis Block (Details) Min Block Input <= 2 Hysteresis Output Input Value Is input > code 6? No Output = 0 Yes Output = Input PWM Value Output = 6 Figure 88. Min Block (Details) PWM Input The PWM input can be assigned to any control bank. When assigned to a control bank, the programmed current in the control bank also becomes a function of the duty cycle at the PWM input. The PWM input is sampled by a digital circuit which outputs a brightness code that is equivalent to the PWM input duty cycle. The resultant brightness value is a combination of the maximum current setting, the brightness registers, and the equivalent PWM brightness code. PWM input Frequency The specified input frequency of the PWM signal is 10 kHz to 80 kHz. The recommended frequency is 30 kHz or greater. The PWM input sampler will operate beyond those frequency limits. Performance will change based on the input frequency used. It is not recommended to use frequencies outside the specified range. Lower PWM input frequency increases the likelihood that the output of the sampler may change and that a single brightness step may be visible on the screen. This may be visible at low brightness because the step change is large relative to the output level. Recommended Settings For best performance of the PWM sampler it is recommended to have a PWM input frequency of at least 30 kHz. The Filter Strength (register 50h) should be set to 03h. The Hysteresis 1 bit should be set in register 05h to 1 when setting the maximum current for bank A. For example if max current is 20 mA, register 05h is set to 14h, change that to 94h for 1 bit hysteresis and a smooth min-to-max brightness transition. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 37 LM3630A SNVS974 – APRIL 2013 www.ti.com Adjustments to PWM sampler The digital sampler has controls for hysteresis and minimum output brightness which allow the optimization of sampler output. The default hysteresis mode of the PWM sampler requires detecting a two code change in the input to increase brightness. Reducing the hysteresis to change on 1 code will allow a smoother brightness transition when the brightness control is swept across the screen in a system. The filter strength bits affect the speed of the output transitions from the PWM sampler. A lower bound to the brightness is enabled by default which will limit the minimum output of the PWM sampler to an equivalent code of 6 when the LEDs are turned on. A detected code of 1 will be forced to off. A minimum 2% PWM input duty cycle is recommended. Input duty cycles of 1% or less will cause delayed off to on transitions. Filter Strength, Register 50h Bits [1:0] • • o Filter Strength controls the amount of sampling cycles that are fed back to the PWM input sampler. A filter strength of 00b allows the output of the PWM sampler to change on every Sample Period. A filter strength of 01b allows the output of the PWM sampler to change every two Sample Periods. A filter strength of 10b allows the output of the PWM sampler to change every four Sample Periods. A filter strength of 11b allows the output of the PWM sampler to change every eight Sample Periods. o The effect of setting this value to 11b forces the output of the PWM sampler to change less frequently then lower values. The benefit is this will reduce the appearance of flicker because the output is slower to change. The negative is that the output is slower to change. Hysteresis 1 bit, Register 05h, Bit 7 • • o The default setting for the LM3630A has Bit 7 of register 05h is 0b. This requires the detection of a PWM input change that is at least 3 equivalent codes higher than the present code. If this bit is set to 1b, the hysteresis is turned off and the PWM sampler output is allowed to change by 2 code. o Setting this bit to 1b will turn off the 2 code requirement for the PWM sampler output to change. The benefit is the output change will be smoother. The negative is that there may be some PWM input value where the output could change by one code and it might appear as flicker. Lower Bound Disable, Register 05h, Bit 6 • • • o The default setting for the LM3630A has Bit 6 of register 05h is 0b. This turns on the lower bound where the minimum output value of the PWM sampler is an equivalent code of 6. If the PWM sampler detects an equivalent code of 0 or 1, the output will be 0 and the LEDs will be off. If the PWM sampler detects an equivalent code of 2 through 6, a current equal to code 6 will be output. Detection of any higher code will output that code conforming to the rules of Hysteresis above. o Setting Bit 6 of register 05h to 1b can be used to allow the output to be below an equivalent code 6. The output of the PWM sampler will match the input pulse width conforming to the rules of Hysteresis and equivalent codes 1, 2, 3, 4, and 5 are also allowed. The benefit is the output is allowed to go dimmer than in the default mode. The negative is at the low codes of 1 and 2, the LEDs may not turn on or the LEDs may appear to flicker. o Disabling the Lower Bound (05h Bit 6 = 1b) allows the minimum duty cycle to be detected at 0.35% PWM input duty cycle. At 30kHz PWM input frequency, the minimum pulse width required to turn on the LEDs is 0.39% X 33 µS = 129 ns. There is no specified tolerance to this value. Minimum TON Pulse Width The minimum TON pulse width required to produce a non-zero output is dependent upon the LM3630A settings. The default setting of the LM3630A requires a minimum of 0.78% duty cycle for the output to be turned on. Because the lower bound feature is enabled, a value of 0.78% (equivalent brightness code 2) up to 2.35% (equivalent brightness code 6) will all produce an output equivalent to brightness code 6. At 30 kHz PWM input frequency, the minimum pulse width required to turn on the LEDs is 0.78% X 33uS = 260ns. Because of the hysteresis on the PWM input, this pulse width may not be sufficient to turn on the LEDs. It is recommended that a minimum pulse width of 2% be used. 2% X 33 µS = 660 ns at 30 kHz input frequency. Disabling the Lower Bound as described will allow a smaller minimum pulse width. 38 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 Maximum Power Output The LM3630A's maximum output power is governed by two factors: the peak current limit (ICL = 1.2A max.), and the maximum output voltage (VOVP = 40V min.). When the application causes either of these limits to be reached it is possible that the proper current regulation and matching between LED current strings will not be met. In the case of a peak current limited situation, when the peak of the inductor current hits the LM3630A's current limit the NFET switch turns off for the remainder of the switching period. If this happens, each switching cycle the LM3630A begins to regulate the peak of the inductor current instead of the headroom across the current sinks. This can result in the dropout of the feedback-enabled current sinks and the current dropping below its programmed level. The peak current in a boost converter is dependent on the value of the inductor, total LED current (IOUT), the output voltage (VOUT) (which is the highest voltage LED string + 0.3V regulated headroom voltage), the input voltage VIN, and the efficiency (Output Power/Input Power). Additionally, the peak current is different depending on whether the inductor current is continuous during the entire switching period (CCM) or discontinuous (DCM) where it goes to 0 before the switching period ends. For Continuous Conduction Mode the peak inductor current is given by: IPEAK = VIN x efficiency VIN IOUT x VOUT x 1+ VOUT 2 x fsw x L VIN x efficiency (4) For Discontinuous Conduction Mode the peak inductor current is given by: IPEAK = 2 x IOUT fsw x L x efficiency x VOUT - VIN x efficiency (5) To determine which mode the circuit is operating in (CCM or DCM) it is necessary to perform a calculation to test whether the inductor current ripple is less than the anticipated input current (IIN). If ΔIL is < then IIN then the device will be operating in CCM. If ΔIL is > IIN then the device is operating in DCM. VIN x efficiency VIN IOUT x VOUT x 1> VOUT VIN x efficiency fsw x L (6) Typically at currents high enough to reach the LM3630A's peak current limit, the device will be operating in CCM. The following figures show the output current and output voltage derating for a 10 µH and a 22 µH inductor, at switch frequencies of 500 kHz and 1 MHz. A 10 µH will typically be a smaller device with lower on resistance, but the peak currents will be higher. A 22 µH provides for lower peak currents, but to match the DC resistance of a 10 µH requires a larger sized device. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 39 LM3630A SNVS974 – APRIL 2013 www.ti.com Maximum Boost Output Power vs VIN, Freq=500kHz, L=10uH 43 42 41 3.0 3.1 40 3.2 3.3 39 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 34 4.3 4.4 33 4.5 4.6 32 4.7 4.8 31 4.9 5.0 30 5.1 5.2 5.3 5.4 38 Vout (V) 37 36 35 Freq = 500kHz L = 10uH VIN = 3.0V to 5.5V 29 28 5.5 27 0 10 20 30 40 50 60 70 80 IOUT (mA) C002 Figure 89. Maximum Boost Output Power vs VIN, Freq=1MHz, L=10uH 43 42 Vout (V) 41 40 39 38 Freq = 1MHz L = 10uH VIN = 3.0V to 5.5V 37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 36 0 10 20 30 40 50 60 70 80 IOUT (mA) C002 Figure 90. 40 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A LM3630A www.ti.com SNVS974 – APRIL 2013 Vout (V) Maximum Boost Output Power vs VIN, Freq=500kHz, L=22uH 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 Freq = 500kHz L = 22uH VIN = 3.0V to 5.5V 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 0 10 20 30 40 50 60 70 80 IOUT (mA) C002 Figure 91. Maximum Boost Output Power vs VIN, Freq=1MHz, L=22uH 41 40 39 3.0 3.1 38 3.2 3.3 3.4 3.5 3.6 3.7 34 3.8 3.9 33 4.0 4.1 32 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 37 36 Vout (V) 35 31 30 29 28 27 Freq = 1MHz L = 22uH VIN = 3.0V to 5.5V 26 25 5.5 24 0 10 20 30 40 50 60 70 80 IOUT (mA) C002 Figure 92. Inductor Selection The LM3630A is designed to work with a 10 µH to 22 µH inductor. When selecting the inductor, ensure that the saturation rating for the inductor is high enough to accommodate the peak inductor current . The following equation calculates the peak inductor current based upon LED current, VIN, VOUT, and Efficiency. I PEAK = I LED VOUT + 'I L × K VIN (7) where: Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A 41 LM3630A SNVS974 – APRIL 2013 'IL = www.ti.com VIN x (VOUT - VIN ) 2 x f SW x L x VOUT (8) When choosing L, the inductance value must also be large enough so that the peak inductor current is kept below the LM3630A's switch current limit. This forces a lower limit on L given by the following equation. VIN x (VOUT - VIN) L> § I LED _ MAX x VOUT © K x VIN 2 x f SW x VOUT x ¨ ¨I SW_MAX - · ¸¸ ¹ (9) ISW_MAX is given in the Electrical Table, efficiency (η) is shown in theTYPICAL PERFORMANCE CHARACTERISTICS , and ƒSW is typically 500 kHz or 1 MHz. Table 4. Inductors Manufacturer Part Number Value Size Current Rating DC Resistance TDK VLF4014ST100M1R0 10 µH 3.8 mm x 3.6 mm x 1.4 mm 1A 0.22 Ω TDK VLF302512MT-220M 22 µH 3 mm x 2.5 mm x 1.2 mm 0.43A 0.583 Ω 42 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LM3630A PACKAGE OPTION ADDENDUM www.ti.com 9-May-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Top-Side Markings (3) (4) LM3630ATME ACTIVE DSBGA YFQ 12 250 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM -40 to 85 D6 LM3630ATMX ACTIVE DSBGA YFQ 12 3000 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM -40 to 85 D6 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Top-Side Marking for that device. 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Addendum-Page 1 Samples MECHANICAL DATA YFQ0012xxx D 0.600 ±0.075 E TMD12XXX (Rev B) D: Max = 1.94 mm, Min = 1.88 mm E: Max = 1.42 mm, Min = 1.36 mm 4215079/A NOTES: A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994. B. This drawing is subject to change without notice. www.ti.com 12/12 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. 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