LM3553SDX/NOPB

LM3553 www.ti.com SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 LM3553 1.2A Dual Flash LED Driver System with I2C Compatible Interface Check for Samples: LM3553 FEATURES 1 • 2 • • • • • • • • • • • • Accurate and Programmable LED Current up to 1.2A in 128 Steps Total Solution Size < 30mm2 90% Peak Efficiency Drives 2 LEDs in Series with 1.2A from 5V Input Drives 2 LEDs in Series with 600mA from 3.0V Input Drives 1 LED with 1.2A from 3.0V Input Adjustable Over-Voltage Protection Allows for Single or Series LED Operation Four Operating Modes: Torch, Flash, Indicator, and Voltage Mode (4.98V) Programmable Flash Pulse Safety Timer in 16 Steps TX Input Ensures Synchronization with RF Power Amplifier Pulse or Prevents LED from Overheating LED Disconnect During Shutdown Flash/Imager Synchronization via FEN Pin Active Low Hardware Reset • • Multi-Function Pin (RESET and GPIO) Low Profile 12-pin WSON Package (DQB0012A: 3mm x 3mm x 0.8mm, 0.4mm pitch) APPLICATIONS • • • Camera Phone LED Flash Smartphone and PDA Flash LED Backlight DESCRIPTION The LM3553 is a fixed frequency, current mode stepup DC/DC converter with two regulated current sinks. The device is capable of driving loads up to 1.2A from a single-cell Li-Ion battery. The LM3553 includes a TX pin that forces Torch mode during a flash event allowing for synchronization between the RF power amplifier and Flash/Torch modes. It also includes a multi-function pin (M/F) that can serve as a GPIO and a hardware RESET pin. The LM3553 is available in a 3mm by 3mm package. Typical Application Circuits 2.2 PH COUT 4.7 PF SW OVP 600 mA Flash Current COUT D1 2.5 2.25 L 9.0 D1 - D2 FEN IC 9.0 1.28 + VIN CIN 10 PF LM3553 TX M/F RSET CIN 0.5 2 ISET GND SCL SDA RSET VIO 29.25mm with 0.4mm spacing around large components (IC and L) Components: L = Toko FDSE0312-2R2M CIN = Murata GRM188R60J106ME47D COUT = Murata GRM21BR61E475KA12L LEDs = Lumileds LXCL ± PWF3 Or equivalent Figure 1. Figure 2. Solution Size 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 © 2008–2013, Texas Instruments Incorporated LM3553 SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Connection Diagram 12 Pin 3mm x 3mm WSON Package DQB0012A 1 12 12 2 11 11 10 10 9 9 5 8 8 5 6 7 7 6 3 Die-Attach Pad (DAP) 4 GND 1 Die-Attach Pad (DAP) GND 2 3 4 Bottom View Top View PIN DESCRIPTIONS Pin Name Function 4 VIN Input Voltage. Input range: 2.7V to 5.5V. 5 SW Switch Pin 6 OVP Over Voltage Protection Pin 2, 11 D1, D2 DAP GND Ground 1 ISET Current sense input. Connect a 1% 16.5kΩ resistor to ground to set the full scale LED current. 3 FEN Flash enable pin. Regulated current sink inputs 8 SCL Serial clock pin. 10 SDA Serial data I/O pin. 9 VIO Digital Reference Voltage level input pin. 7 TX RF PA synchronization control pin. High = Forced Torch mode. 12 M/F Hardware RESET or General purpose I/O. Function set through Multi-Function Control Register These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Absolute Maximum Ratings (1) (2) (3) VIN pin: Voltage to GND -0.3V to 6V SW, OVP pin: Voltage to GND -0.3V to 25V D1, D2 pins: Voltage to GND -0.3V to 25V VIO, SCL, SDA -0.3V to 6V TX, FEN, M/F Continuous Power Dissipation -0.3V to 6V (4) Internally Limited Junction Temperature (TJ-MAX ) 150°C Storage Temperature Range -65°C to +150 (5) Maximum Lead Temperature (Soldering) (6) ESD Rating Human Body Model (1) (2) (3) (4) (5) (6) 2 2.5kV Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of the device is specified. Operating Ratings do not imply performance limits. For performance limits and associated test conditions, see the Electrical Characteristics tables. All voltages are with respect to the potential at the GND pin. If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications. Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=140ºC (typ.) and disengages at TJ=120ºC (typ.). For detailed soldering specifications and information, please refer to Texas Instruments Application Note: AN-1187 SNOA401 for Recommended Soldering Profiles. The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. (MIL-STD-883 3015.7) Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 LM3553 www.ti.com Operating Ratings SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 (1) (2) Input Voltage Range 2.7V to 5.5V Junction Temperature (TJ) Range Ambient Temperature (TA) Range (1) (2) (3) -30°C to +125°C (3) -30°C to +85°C Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of the device is specified. Operating Ratings do not imply performance limits. For performance limits and associated test conditions, see the Electrical Characteristics tables. All voltages are with respect to the potential at the GND pin. 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). Thermal Properties Junction-to-Ambient Thermal Resistance (θJA), DQB0012A Package (1) (1) 36.7°C/W Junction-to-ambient thermal resistance is highly application and board-layout dependent. In applications where high maximum power dissipation exists, special care must be paid to thermal dissipation issues in board design. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 3 LM3553 SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Electrical Characteristics Limits in standard typeface are for TA = +25°C. Limits in boldface type apply over the full operating junction temperature range (-30°C ≤ TJ ≤ +125°C). Unless otherwise noted: VIN = 3.6V, RSET = 16.5kΩ, VD1 = VD2 = 500mV, VFB bit = '0', FEN = '0', TX = '0', Flash Current Level = Full-Scale. (1) (2) (3) Symbol ILED-SUM Parameter Flash LED Current: ID1+ ID2 Conditions Flash Mode VDX = Regulation Voltage Min Typ Max 930 1020 1110 mA Flash Mode VDX = Regulation Voltage RSET = 13.7kΩ ILED-IND Indicator Current Level Indicator Mode VMREG Output Voltage Regulation in Voltage Mode VM = '1', EN1 = EN0 = '0' No Load IQ Quiescent Supply Current ISD Units 1200 20 4.65 mA 4.98 5.30 V VD1,D2 = 0V (Switching) 1.0 1.2 mA Shutdown Supply Current Device Disabled 3.8 6.0 µA IDx / ISET LED Current to Set Current Ratio IDx= 500mA VSET ISET Pin Voltage VD1,D2 Current Sink Regulation Voltage VFB Bit = '0' 450 VFB Bit = '1' 350 IDx-MATCH Current Sink Matching VDX = Regulation Voltage RDSON NMOS Switch Resistance 6770 A/A 1.24 V mV 2 % Ω 0.25 OCL Bit = '0' 2.2 2.5 2.8 OCL Bit = '1' 1.53 1.70 1.87 ICL NMOS Switch Current Limit IL-SW SW Pin Leakage Current Switch Off, VSW=3.6V, OVP Mode = '0' 10 nA IL-Dx D1, D2 Pin Leakage VDx = 3.5V 10 nA VOVP Output Over-Voltage Protection Trip Point OVP Mode = '1' 18.00 18.90 19.65 OVP Mode = '0' 5.4 5.6 5.85 Over-Voltage Protection Hysteresis OVP to Normal Operation OVP Mode = '1' 1.6 OVPHyst OVP Mode = '0' 0.6 IL-OVP OVP Pin Leakage Current VOVP=3.6V fSW Switching Frequency tFD-MIN Minimum Flash Duration Step 12.8 µsec. DMAX Maximum Duty Cycle 92 % DMIN Minimum Duty Cycle 6 ThTX,F-EN TX, FEN Pin Threshold 1.2 tFD-MIN = 16 ÷ fSW V V 10 1.0 A nA 1.35 MHz % On 1.0 VIN Off 0 0.6 Input Logic High "1" 0.94 VIN Input Logic Low "0" 0 0.64 V Multi-Function Pin (M/F) Voltage Specifications VM/F Multi-Function Pin Threshold Voltages VOL Output Logic Low "0" ILOAD = 4.2mA, GPIO Mode V 400 mV I2C Compatible Voltage Specifications (SCL, SDIO, VIO) VIO Serial Bus Voltage Level 1.45 VIN V VIL Input Logic Low "0" VIO = 3.0V 0 0.38 ×VIO V VIH Input Logic High "1" VIO = 3.0V 0.55 × VIO VIO V VOL Output Logic Low "0" ILOAD = 3.7mA 400 mV (1) (2) (3) 4 All voltages are with respect to the potential at the GND pin. Min and Max limits are specified by design, test, or statistical analysis. Typical (Typ) numbers represent the most likely norm. Unless otherwise specified, conditions for Typ specifications are: VIN = 3.6V and TA = 25ºC. All testing for the LM3553 is done open-loop. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 LM3553 www.ti.com SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 Electrical Characteristics (continued) Limits in standard typeface are for TA = +25°C. Limits in boldface type apply over the full operating junction temperature range (-30°C ≤ TJ ≤ +125°C). Unless otherwise noted: VIN = 3.6V, RSET = 16.5kΩ, VD1 = VD2 = 500mV, VFB bit = '0', FEN = '0', TX = '0', Flash Current Level = Full-Scale. (1)(2)(3) Symbol Parameter Conditions Min Typ Max Units I2C Compatible Interface Timing Specifications (SCL, SDIO, VIO) t1 SCL (Clock Period) 2.5 µs t2 Data In Setup Time to SCL High 100 ns t3 Data Out stable After SCL Low 0 ns t4 SDA Low Setup Time to SCL Low (Start) 100 ns t5 SDA High Hold Time After SCL High (Stop) 100 ns Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 5 LM3553 SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics Unless otherwise specified: TA = 25°C; VIN = 3.6V; VM/F = VIN; RSET = 16.5kΩ; CIN= 10µF, COUT = 10µF;L = 2.2µH; VFB bit = CL bit = '0'; OVP bit = '0' for 1 LED and VFB = '1' for two series LEDs;. Maximum LED Drive Current @ VIN = 3.6V 1.6 1.2A Flash Line Regulation 1.4 TA = -30°C and +25°C VLED = 3.65V @ +25°C TA = +25°C 1.3 TA = +85°C ILED (A) ILED (A) 1.2 0.8 1.2 0.4 TA = -30°C 1.1 TA = +85°C VLED = 3.5V @1.2A 0.0 0 32 64 96 1.0 3.0 128 3.5 4.0 Figure 3. 5.0 5.5 Figure 4. 1.0A Flash Line Regulation Voltage Mode Line Regulation 1.1 5.250 TA = +25°C IOUT = 500 mA 5.125 VOUT (V) 1.1 ILED (A) 4.5 VIN (V) BRIGHTNESS CODE (#) 1.0 TA = +85°C 5.000 TA = -30°C TA = +85°C 4.875 TA = -30°C VLED = 3.7V @ +25°C 0.9 3.0 3.5 4.0 4.5 5.0 4.750 2.7 5.5 3.1 3.5 3.9 VIN (V) 4.7 5.1 5.5 Figure 5. Figure 6. Voltage Mode Load Regulation Input Current and LED Efficiency with 1A Flash Current 90 2.40 VLED = 3.7V and ILED = 1A TA = +25° IOUT = 100 mA 2.00 5.25 IIN (A) IOUT = 500 mA 5.00 4.75 äLED IIN I OUT = 300 mA VOUT (V) 4.3 VIN (V) 5.50 4.50 2.7 TA = +25°C 80 1.60 70 1.20 60 äLED (%) 1.0 IOUT = 700 mA 0.80 2.9 3.1 3.5 3.9 4.3 4.7 5.1 3.4 3.9 4.5 5.0 50 5.5 5.5 VIN (V) VIN (V) Figure 7. 6 Figure 8. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 LM3553 www.ti.com SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 Typical Performance Characteristics (continued) Unless otherwise specified: TA = 25°C; VIN = 3.6V; VM/F = VIN; RSET = 16.5kΩ; CIN= 10µF, COUT = 10µF;L = 2.2µH; VFB bit = CL bit = '0'; OVP bit = '0' for 1 LED and VFB = '1' for two series LEDs;. Input Current and LED Efficiency with 1.2A Flash Current 2.80 Input Current and LED Efficiency with 500mA Flash Current through 2 Series LEDs 90 1.60 80 1.35 90 VLED = 3.8V and ILED = 1.2A äLED 80 äLED IIN (A) äLED (%) IIN (A) 70 70 1.10 IIN äLED (%) IIN 2.20 1.60 60 60 0.85 2 LEDs in Series 1.00 3.0 3.5 4.0 4.5 5.0 50 5.5 0.60 3.0 VLED = 3.35V and ILED = 500 mA 3.5 4.0 VIN (V) 4.5 5.0 50 5.5 VIN (V) Figure 9. Figure 10. Input Current and LED Efficiency with 600mA Flash Current through 2 Series LEDs Input Current vs VIN 1 LED @ 1.2A and 2 LEDs @ 600mA 2.20 90 1.85 80 2.8 2.4 2.0 IIN (A) IIN (A) 70 1.50 äLED (%) 1 LED @ 1.2A äLED IIN 2 LEDs @ 600 mA 1.6 60 1.15 1.2 2 LEDs in Series VLED = 3.4V and ILED = 600 mA 0.80 3.0 3.5 4.0 4.5 5.0 50 5.5 0.8 2.7 3.1 3.5 3.9 VIN (V) 4.3 4.7 5.1 5.5 VIN (V) Figure 11. Figure 12. LED Efficiency vs VIN 1 LED @ 1.2A and 2 LEDs @ 600mA Converter Efficiency vs VIN 100 100 Voltage Mode with IOUT = 500 mA 2 LEDs @ 600 mA ηCONVERT ER (%) 90 äLED (%) 80 1 LED @ 1.2A 60 80 2 LEDs @ 500 mA with VLED(total) = 6.725V 70 60 1 LED @ 1A with VLED = 3.7V 50 40 2.7 3.1 3.5 3.9 4.3 4.7 5.1 40 5.5 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 VIN (V) VIN (V) Figure 13. Figure 14. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 7 LM3553 SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com BLOCK DIAGRAM OVP SW SW Driver OVP SWITCH CONTROLLER THERMAL SHUTDOWN OSC VREF CURRENT LIMIT + - VIN RAMP gm LM3553 ¦ RESET/GPIO M/F + RZ 0.35V or 0.450V MIN. Dx VOLTAGE SELECT CC VIO SDA D2 ISTEP CTRL 2 SCL D1 TORCH CTRL I C INTERFACE/ CONTROL LOGIC/ REGISTERS Tx FLASH CTRL Current Control TIME-OUT CTRL FEN GND D1 Current Sink D2 Current Sink RSET Circuit Description CIRCUIT COMPONENTS FEN Pin The flash enable pin, FEN, provides an external method (non-I2C) for starting the flash pulse. When FEN is pulled high, logic '1', the flash current level defined through the I2C interface, will be delived to the Flash LED. If the FEN pin is driven low during the flash pulse, the flash event will stop. In the event that FEN is not pulled low during the flash pulse, the LM3553 will continue to deliver the flash current until the safety timer duration (set through the I2C interface) is reached. The LM3553 does not provide a fixed off-time after the flash pulse has ended. Most flash LED manufacturers require that the flash pulse duration be 10% of the total Flash cycle. Example: If the flash pulse duration is set to be 200 milliseconds (Flash Duration Code= 0011), the recommended off time for the LED would be 1.8 seconds. Please consult the LED manufacturers datasheet for exact timing requirements. If the LM3553 is placed in indicator mode or torch mode through the I2C interface and the FEN pin is pulled high and then low, at the end of the flash event, the LM3553 will return to the mode stored in the General Purpose Register. It is recommended that an external pull-down be placed between the FEN pin and GND to prevent unwanted LED flashing during system start-up due to unknown control logic states. 8 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 LM3553 www.ti.com SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 TX Pin The transmission pin (TX) can be used to limit the current drawn from the battery during a PA transmission. When the TX pin is driven high (logic '1') during a flash pulse, the LM3553 will switch to the programmed torch current level. Once the TX pin is driven low (logic '0'), the LM3553 will return to the flash current if this event occurs within the original flash duration. It is recommended that an external pull-down be placed between the TX pin and GND to prevent unwanted LED flashing during system start-up due to unknown control logic states. M/F Pin The multi-function pin (M/F) can be configured to provide hardware RESET or a general purpose input/output (GPIO). All functionality is programmed through the I2C compatible interface and set in the M/F pin functionality control register (address 0x20). The default function is a RESET, where a logic '1' places the part in the normal operating mode, and a logic '0' places the part into a RESET state. A reset condition will place all LM3553 registers into their default states. Connection Diagram TX PA Tx SDA LM3553 PP/PC SCL FEN Imager Figure 15. Typical System Configuration 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, the state of the data line can only be changed when CLK is LOW. SCL SDA data change allowed data valid data change allowed data valid data change allowed Figure 16. Data Validity Diagram A pull-up resistor between VIO and SDA must be greater than [(VIO-VOL) / 3.7mA] 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. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 9 LM3553 SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com 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. The data on SDA line must be stable during the HIGH period of the clock signal (SCL). In other words, the state of the data line can only be changed when CLK is LOW. SDA SCL S P START condition STOP condition Figure 17. Start and Stop Conditions TRANSFERRING DATA Every byte put on the SDA line must be eight bits long, with the most significant bit (MSB) being 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 LM3553 pulls down the SDA line during the 9th clock pulse, signifying an acknowledge. The LM3553 generates an acknowledge after each byte has been 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 LM3553 address is 53h. 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. ack from slave ack from slave start msb Chip Address lsb w ack msb Register Add lsb ack start Id = 53h w ack addr = 10h ack msb ack from slave DATA lsb ack stop ack stop SCL SDA data = 08h w = write (SDA = "0") ack = acknowledge (SDA pulled down by the slave) id = chip address, 53h for LM3553 Figure 18. Write Cycle I2C COMPATIBLE CHIP ADDRESS The chip address for LM3553 is 1010011, or 53hex. 10 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 LM3553 www.ti.com SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 MSB LSB ADR6 bit7 ADR5 bit6 ADR4 bit5 ADR3 bit4 ADR2 bit3 ADR1 bit2 ADR0 bit1 1 0 1 0 0 1 1 R/W bit0 2 I C Slave Address (chip address) INTERNAL REGISTERS OF LM3553 Register Internal Hex Address Power On Value General Purpose Register 0x10 0001 1000 Multi-Function Pin Control Register 0x20 1110 0000 Current Step Time Register 0x50 1111 1100 Torch Current Control Register 0xA0 1000 0000 Flash Current Control Register 0xB0 1000 0000 Flash Duration Control Register 0xC0 1111 0000 General Purpose Register General Purpose Control Register Address: 0x10 MSB 0 bit7 0 bit6 VFB bit5 1 bit4 1 bit3 LSB VM bit2 EN1 bit1 EN0 bit0 EN0-EN1: Set Flash LED mode Indicator Mode sets ILED = 20mA. In this mode, D1 is enabled and D2 is disabled. VM: Enables Voltage Mode. Current sinks D1 and D2 are turned off and the LM3553 will operate in a regulated voltage boost mode. Setting the VM bit to a '1' does not override the EN0 and EN1 bits stored in the general purpose register. The default setting is '0'. If the LM3553 is in Voltage Mode and an indicator, torch or flash command is issued, the LM3553 will turn on the D1 and D2 current sources and begin regulating the output voltage to a value equal to VFB (350mV or 450mV) + VLED. VM EN1 EN0 Function 0 0 0 Shutdown 0 0 1 Indicator Mode 0 1 0 Torch Mode 0 1 1 Flash Mode 1 0 0 Voltage Mode 1 0 1 Indicator Mode 1 1 0 Torch Mode 1 1 1 Flash Mode Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 11 LM3553 SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com VFB: Selects the regulation voltage for the LM3553. Setting this VFB bit to a '0' sets the regulation voltage to 450mV while setting the VFB bit to a '1' sets the regulation voltage to 350mV. Setting the VFB bit to a '1' during torch mode and/or lower current flash modes (ILED < 1A) will help improve the LED efficiency of the LM3553. M/F Pin Control Register Multi-Function Pin Control/Options Register Address: 0x20 MSB 1 bit7 1 bit6 1 bit5 OCL bit4 OVP bit3 DATA bit2 LSB MODE bit1 RESET bit0 RESET: Enables M/F as hardware RESET. '0' = Hardware RESET, .'1' = GPIO or current sink depending on the MODE bit. Default = '0' MODE: Sets M/F mode. Default for M0DE = '0'. '0' = GPI, and'1' = GPO NOTE When M/F is configured as an input, data is transfered from GPI to DATA whenever an I2C write command is issued to the LM3553. When configuring M/F as a GPO, the first write needs to take the LM3553 out of RESET mode and a second write can then set the pin to the GPO. DATA: GPIO Data. When the M/F is configured as an output (GPO), DATA sets the GPO level. Example: DATA = '1', M/F is set high or logic '1'. When the M/F pin is configured as an input (GPI), DATA stores the GPI level. Example: M/F = '1', DATA will be set to a '1'. Default for DATA = '0'. OVP: Enables high-voltage OVP (OVP Bit ='1') or low-voltage OVP (OVP Bit ='0'). Default = low-voltage mode '0' OCL: SW Pin Current Limit Selector Bit: If OCL = '0', the inductor current limit is 2.5A typ. If OCL = '1', the inductor current limit is 1.7A typ. Table 1. M/F Functionality Configuration Table RESET MODE M/F Function 0 X RESET 1 0 GPI 1 1 GPO Current Step Time Register Current Step Time Register Address: 0x50 MSB 1 bit7 1 bit6 1 bit5 1 bit4 1 bit3 LSB 1 bit2 ST1 bit1 ST0 bit0 ST1-ST0: Sets current level stepping time for D1 and D2 during the beginning and end of the flash or torch current waveform. '00' = 25µs, '01' = 50µs, '10' = 100µs, '11' = 200µs. The current ramp-up/ramp-down times can be approximated by the following equation: TRAMPUP/RAMPDOWN = (NFLASH - NSTART + 1) × tSTEP where • • N is equal to the decimal value of the brightness level (0 ≤ NFLASH ≤ 127 and 0 ≤ NSTART ≤ 31) NSTART = NTORCH if Torch is enabled before going into a flash. If going straight into a flash from an off-state, NSTART = 0. 12 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 LM3553 www.ti.com SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 Torch Current Control Register TORCH Current Control Register Address: 0xA0 MSB 1 bit7 0 bit6 0 bit5 TC4 bit4 TC3 bit3 LSB TC2 bit2 TC1 bit1 TC0 bit0 TC6-TC0: Sets Torch current level for D1 and D2. xxx1 1111 = Fullscale Flash Current Control Register FLASH Current Control Register Address: 0xB0 MSB 1 bit7 FC6 bit6 FC5 bit5 FC4 bit4 FC3 bit3 LSB FC2 bit2 FC1 bit1 FC0 bit0 FC6-FC0: Sets Flash current level for D1 and D2. x111 1111 = Fullscale Current Level Equation The Full-Scale Flash Current Level is set through the use of an external resistor (RSET) connected to the ISET pin. The RSET selection equation can be used to set the current through each of the two current sinks, D1 and D2. RSET = 6770 × 1.24V ÷ IDx Table 2. RSET Selection Table IFlash = ID1 + ID2 RSET 500mA 33.6kΩ 600mA 28kΩ 1A 16.8kΩ 1.2A 14kΩ The current through each current sink, D1 and D2, can be approximated by the following equation using the values stored in either the Torch or Flash Current Control registers. IFLASH≊ (N + 1) × ILED_TOTAL ÷ 128 where N is the decimal equivalent number (0 ≤ N ≤ 127 for Flash and 0 ≤ N ≤ 31 for Torch) stored in the Torch or Flash Current control registers and ILED_TOTAL = ID1 + ID2 @ Full-scale. Brightness codes 0 through 4 are repeated and each sets the total LED current to approximately 40mA. Flash Safety Timer Control Register FLASH Duration Control Register Address: 0xC0 MSB 1 bit7 1 bit6 1 bit5 1 bit4 FD3 bit3 LSB FD2 bit2 FD1 bit1 FD0 bit0 FD3-FD0: Sets Flash Duration for D1 and D2. 1111 = Fullscale Safety Timer Duration Code (Binary) Typical Safety Timer Duration (milliseconds) 0000 50 0001 100 0010 200 0011 300 0100 400 0101 500 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 13 LM3553 SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Safety Timer Duration Code (Binary) Typical Safety Timer Duration (milliseconds) 0110 600 0111 700 1000 800 1001 900 1010 1000 1011 1100 1100 1200 1101 1300 1110 1400 1111 3200 Table 3. LM3553 Functionality Truth Table EN1 EN0 FEN TX Result 0 0 0 0 Shutdown 0 0 0 1 Shutdown 0 0 1 0 Flash 0 0 1 1 Torch 0 1 0 0 Indicator 0 1 0 1 Indicator 0 1 1 0 Flash 0 1 1 1 Torch 1 0 0 0 Torch 1 0 0 1 Torch 1 0 1 0 Flash 1 0 1 1 Torch 1 1 0 0 Flash 1 1 0 1 Torch 1 1 1 0 Flash 1 1 1 1 Torch Safety Timer FEN TX on off on off flash STATE torch off Figure 19. FEN Terminated Pulse 14 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 LM3553 www.ti.com SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 Safety Timer FEN TX on off on off flash STATE torch off Figure 20. Safety Timer Terminated Pulse Safety Timer FEN TX on off on off flash STATE torch off Figure 21. TX Terminated Pulse Application Information INDUCTOR SELECTION The LM3553 is designed to use a 2.2µH inductor. When the device is boosting (VOUT > VIN) the inductor is one of the biggest sources of efficiency loss in the circuit. Therefore, choosing an inductor with the lowest possible series resistance is important. Additionally, the saturation rating of the inductor should be greater than the maximum operating peak current of the LM3553. This prevents excess efficiency loss that can occur with inductors that operate in saturation and prevents over heating of the inductor and possible damage. For proper inductor operation and circuit performance ensure that the inductor saturation and the peak current limit setting of the LM3553 (2.6A or 1.8A) is greater than IPEAK. IPEAK can be calculated by: ILOAD IPEAK = K VOUT u VIN + 'IL where VIN u 'IL = ( VOUT - VIN) 2 u fSW u L u VOUT (1) Table 4. Recommended Inductors Manufacturer Part# L / ISAT Toko FDSE312-2R2M 2.2µH / 2.3A Coilcraft LPS4012-222ML 2.2µH / 2.3A TDK VLF4014ST-2R2M1R9 2.2µH / 2.0A Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM3553 15 LM3553 SNVS414B – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com CAPACITOR SELECTION The LM3553 requires 2 external capacitors for proper operation (CIN = 10µF recommended (4.7µF min.) and COUT = 10µF (single LED) or 4.7µF (series LEDs)). Surface-mount multi-layer ceramic capacitors are recommended. These capacitors are small, inexpensive and have very low equivalent series resistance (ESR