1.5 A LED Flash Driver with I2C-Compatible Interface ADP1650 FEATURES APPLICATIONS Camera-enabled cellular phones and smart phones Digital still cameras, camcorders, and PDAs FUNCTIONAL BLOCK DIAGRAM INPUT VOLTAGE = 2.7V TO 5.0V 10µF 1.0µH TX1/TORCH VIN GPIO1 SW VOUT TX2/ILED/ADC GPIO2 10µF ADP1650 STROBE LED_OUT MAX 1.5A SCL SGND PGND 08837-001 SDA EN Figure 1. Li-ION + C1 L1 PGND Li-ION + C2 INDUCTOR DIGITAL INPUT/ OUTPUT AREA = 16.4mm 2 LED ANODE 08837-002 Ultracompact solution Small, 2 mm × 1.5 mm, 12-ball WLCSP package Thin, 3 mm × 3 mm × 0.75 mm, 10-lead LFCSP package Smallest footprint, 1 mm height, 1 μH power inductor LED current source for local LED grounding Simplified routing to/from LED Improved LED thermals Synchronous 3 MHz PWM boost converter, no external diode High efficiency: 90% peak Reduces high levels of input battery current during flash Limits battery current drain in torch mode I2C programmable Currents up to 1500 mA in flash mode for 1 LED with ±7% accuracy over all conditions Currents up to 200 mA in torch mode Programmable dc battery current limit (4 settings) Programmable flash timer up to 1600 ms Low VBAT mode to reduce LED current automatically 4-bit ADC for LED VF, die/LED temperature readback Control I2C-compatible control registers External STROBE and torch input pins 2 transmitter mask (TxMASK) inputs Safety Thermal overload protection Inductor fault detection LED short-/open-circuit protection Figure 2. PCB Layout (WLCSP) GENERAL DESCRIPTION The ADP1650 is a very compact, highly efficient, single white LED flash driver for high resolution camera phones that improves picture and video quality in low light environments. The device integrates a programmable 1.5 MHz or 3 MHz synchronous inductive boost converter, an I2C-compatible interface, and a 1500 mA current source. The high switching frequency enables the use of a tiny, 1 mm high, low cost, 1 μH power inductor, and the current source permits LED cathode grounding for thermally enhanced, low EMI, and compact layouts. The LED driver maximizes efficiency over the entire battery voltage range to maximize the input-power-to-LED-power conversion and to minimize battery current draw during flash events. A programmable dc battery current limit safely maximizes LED current for all LED VF and battery voltage conditions. Two independent TxMASK inputs permit the flash LED current and battery current to reduce quickly during a power amplifier current burst. The I2C-compatible interface enables the programmability of timers, currents, and status bit readback for operation monitoring and safety control. The ADP1650 is available in a compact 12-ball, 0.5 mm pitch WLCSP package and a 10-lead LFCSP package, and operates within specification over the full −40°C to +125°C junction temperature range. Rev. C Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2010–2011 Analog Devices, Inc. All rights reserved. ADP1650 TABLE OF CONTENTS Features .............................................................................................. 1 Indicator LED Driver................................................................. 14 Applications....................................................................................... 1 Low Battery LED Current Foldback ........................................ 14 Functional Block Diagram .............................................................. 1 Programmable Battery DC Current Limit.............................. 15 General Description ......................................................................... 1 Analog-to-Digital Converter Operation ................................. 15 Revision History ............................................................................... 2 5 V Output Operation ............................................................... 16 Specifications..................................................................................... 3 Safety Features................................................................................. 18 Recommended Specifications: Input and Output Capacitance and Inductance ............................................................................. 5 Short-Circuit Fault ..................................................................... 18 I2C-Compatible Interface Timing Specifications ..................... 5 Dynamic Overvoltage Mode (DOVP) .................................... 18 Absolute Maximum Ratings............................................................ 6 Timeout Fault.............................................................................. 18 Thermal Data ................................................................................ 6 Overtemperature Fault .............................................................. 18 Thermal Resistance ...................................................................... 6 Indicator LED Fault ................................................................... 18 ESD Caution.................................................................................. 6 Current Limit.............................................................................. 18 Pin Configurations and Function Descriptions ........................... 7 Input Undervoltage .................................................................... 18 Typical Performance Characteristics ............................................. 8 Soft Start ...................................................................................... 18 Theory of Operation ...................................................................... 12 Reset Using the Enable (EN) Pin ............................................. 18 White LED Driver ...................................................................... 12 Clearing Faults ............................................................................ 18 Modes of Operation ................................................................... 12 I2C Interface ................................................................................ 19 Assist Light .................................................................................. 13 I2C Register Map............................................................................. 20 Flash Mode .................................................................................. 13 Applications Information .............................................................. 26 Assist-to-Flash Operation ......................................................... 13 External Component Selection ................................................ 26 Torch Mode ................................................................................. 13 PCB Layout...................................................................................... 28 Torch-to-Flash Mode ................................................................. 14 Outline Dimensions ....................................................................... 29 TxMASK Operation................................................................... 14 Ordering Guide .......................................................................... 29 Overvoltage Fault ....................................................................... 18 Frequency Foldback ................................................................... 14 REVISION HISTORY 4/11—Rev. B to Rev. C Added 10-Lead LFCSP Package........................................Universal Changes to Features Section, General Description Section, and Figure 2 Caption ............................................................................... 1 Changes to Table 1............................................................................ 3 Changes to Table 5............................................................................ 6 Added Figure 5; Renumbered Sequentially .................................. 7 Changes to Table 6............................................................................ 7 Changes to PCB Layout Section and Figure 45 Caption........... 28 Added Figure 46.............................................................................. 28 Updated Outline Dimensions ....................................................... 29 Changes to Ordering Guide .......................................................... 29 Changed GND to Power Ground Throughout .............................6 Changed IL to IL, ILED to ILED, LED OUT to LED_OUT, and IBAT to IBAT Throughout ..................................................................8 Change to Figure 10 Caption ...........................................................8 Change to Figure 11 Caption ...........................................................9 Changed LED_MOD = 10 to LED_MOD = 11 in Figure 32 ... 14 Changes to Analog-to-Digital Converter Operation Section and Figure 37 .......................................................................................... 15 Changes to Selecting the Output Capacitor Section.................. 26 2/11—Rev. A to Rev. B Changes to Features Section and General Description Section . 1 Changes to Switching Regulator, Voltage Output Mode, VOUT Voltage Parameter and Digital Inputs/GPIO, Torch Glitch Filtering Delay Parameter, Table 1.................................................. 3 5/10—Revision 0: Initial Version 6/10—Rev. 0 to Rev. A Changes to Contact Information.....................................................1 Rev. C | Page 2 of 32 ADP1650 SPECIFICATIONS VIN 1 = 3.6 V, TJ = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications, unless otherwise noted. Table 1. Parameter 2 SUPPLY Input Voltage Range Undervoltage Lockout Threshold Undervoltage Lockout Hysteresis Shutdown Current (IQ), EN = 0 V Standby Current (ISTBY), EN = 1.8 V Operating Quiescent Current SW Switch Leakage LED DRIVER LED Current Assist Light, Torch Flash LED Current Error—WLCSP LED Current Error—LFCSP LED Current Source Headroom—WLCSP LED Current Source Headroom—LFCSP LED_OUT Ramp-Up Time LED_OUT Ramp-Down Time SWITCHING REGULATOR Switching Frequency Minimum Duty Cycle nFET Resistance—WLCSP pFET Resistance—WLCSP nFET Resistance—LFCSP pFET Resistance—LFCSP Voltage Output Mode VOUT Voltage—WLCSP VOUT Voltage—LFCSP Output Current Line Regulation Load Regulation Conditions Min VIN falling 2.7 2.3 50 TJ = −40°C to +85°C, current into VIN pin, VIN = 2.7 V to 4.5 V TJ = −40°C to +85°C, current into VIN pin, VIN = 2.7 V to 4.5 V Torch mode, LED current = 100 mA TJ = −40°C to +85°C, VSW 3 = 4.5 V TJ = 25°C, VSW 3 = 4.5 V Assist light value setting = 0 (000 binary) Assist light value setting = 7 (111 binary) Flash value setting = 0 (00000 binary) Flash value setting = 24 (11000 binary) ILED = 700 mA to 1100 mA ILED = 300 mA to 650 mA, 1150 mA to 1500 mA ILED = 75 mA to 200 mA ILED = 25 mA to 50 mA ILED = 700 mA to 1100 mA ILED = 300 mA to 650 mA, 1150 mA to 1500 mA ILED = 75 mA to 200 mA ILED = 25 mA to 50 mA Flash, 1200 mA LED current Torch, 200 mA LED current Flash, 1200 mA LED current Torch, 200 mA LED current Typ 2.4 100 0.2 3 5.3 Max Unit 5.0 2.5 150 1 10 V V mV μA μA mA μA μA 2 0.5 25 200 300 1500 −6 −7 −10 −15 −6 −7 −10 −15 +6 +7 +10 +15 +6 +7 +10 +18 290 190 370 220 0.6 0.1 Switching frequency = 3 MHz Switching frequency = 1.5 MHz Switching frequency = 3 MHz Switching frequency = 1.5 MHz ILOAD at VOUT = 300 mA Rev. C | Page 3 of 32 mA mA mA mA % % % % % % % % mV mV mV mV ms ms 2.8 1.4 3 1.5 14 7 60 50 77 85 3.2 1.6 MHz MHz % % mΩ mΩ mΩ mΩ 4.575 4.575 5.000 5.000 5.425 5.500 500 V V mA %/V %/A 0.3 −0.7 ADP1650 Parameter 2 Pass-Through Mode Transition, Flash VIN to LED_OUT, Entry VIN to LED_OUT, Exit Pass-Through Mode Transition, Torch VIN to LED_OUT, Entry VIN to LED_OUT, Exit DIGITAL INPUTS/GPIO Input Logic Low Voltage Input Logic High Voltage GPIO1, GPIO2, STROBE Pull-Down Torch Glitch Filtering Delay INDICATOR LED LED Current Accuracy Short-Circuit Detection Threshold Open-Circuit Detection Threshold ADC Resolution Error Input Voltage Range, GPIO2 SAFETY FEATURES Maximum Timeout For Flash Timer Accuracy DC Current Limit Low VBAT Mode Transition Voltage Error Hysteresis Coil Peak Current Limit Conditions Min Typ Max Unit 1200 mA LED current 1200 mA LED current 580 435 mV mV 200 mA LED current 200 mA LED current 380 285 mV mV 0.54 1.26 From torch rising edge to device start 5.5 390 7 −22 7.5 +22 1.2 2.45 4 External voltage mode VF mode, TJ = 25°C VF mode, TJ = −40°C to +125°C External voltage mode 0 0 DC current value setting = 0 (00 binary) DC current value setting = 1 (01 binary) DC current value setting = 2 (10 binary) DC current value setting = 3 (11 binary) −7.0 1.35 1.55 1.8 2.02 Bits LSB LSB LSB V +7.0 1.65 1.95 2.2 2.5 ms % A A A A 3.2 Peak current value setting = 0 (00 binary) Peak current value setting = 1 (01 binary) Peak current value setting = 2 (10 binary) Peak current value setting = 3 (11 binary) Overvoltage Detection Threshold LED_OUT Short-Circuit Detection Comparator Reference Voltage Thermal Shutdown Threshold TJ Rising TJ Falling 1.55 2.02 2.47 2.7 5.15 50 1.75 2.25 2.75 3.0 5.5 1.2 150 140 1 VIN is the input voltage to the circuit. All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC). 3 VSW is the voltage on the SW switch pin. 2 Rev. C | Page 4 of 32 % V V ±1 ±1 ±1.5 0. 5 1600 1.5 1.75 2.0 2.25 V V kΩ ms 1.95 2.5 3.0 3.3 5.9 1.3 % mV A A A A V V °C °C ADP1650 RECOMMENDED SPECIFICATIONS: INPUT AND OUTPUT CAPACITANCE AND INDUCTANCE Table 2. Parameter CAPACITANCE Input Output MINIMUM AND MAXIMUM INDUCTANCE Symbol CMIN L Conditions Min Typ Max Unit TA = −40°C to +125°C TA = −40°C to +125°C TA = −40°C to +125°C 4.0 3.0 0.6 10 10 1.0 20 1.5 μF μF μH I2C-COMPATIBLE INTERFACE TIMING SPECIFICATIONS Table 3. Parameter 1 fSCL tHIGH tLOW tSU, DAT tHD, DAT tSU, STA tHD, STA tBUF tSU, STO tR tF tSP CB 2 2 Max 400 0.6 1.3 100 0 0.6 0.6 1.3 0.6 20 + 0.1 CB 2 20 + 0.1 CB2 0 Unit kHz μs μs ns μs μs μs μs μs ns ns ns pF 0.9 300 300 50 400 Description SCL clock frequency SCL high time SCL low time Data setup time Data hold time Setup time for repeated start Hold time for start/repeated start Bus free time between a stop and a start condition Setup time for stop condition Rise time of SCL and SDA Fall time of SCL and SDA Pulse width of suppressed spike Capacitive load for each bus line Guaranteed by design. CB is the total capacitance of one bus line in picofarads. SDA tLOW tR tF tSU, DAT tF tHD, STA tSP tBUF tR SCL S tHD, DAT tHIGH tSU, STA Sr S = START CONDITION Sr = REPEATED START CONDITION P = STOP CONDITION tSU, STO P S 08837-003 1 Min Figure 3. I2C-Compatible Interface Timing Diagram Rev. C | Page 5 of 32 ADP1650 ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Table 4. Parameter VIN, SDA, SCL, EN, GPIO1, GPIO2, STROBE, LED_OUT, SW, VOUT to Power Ground PGND to SGND Ambient Temperature Range (TA) Junction Temperature Range (TJ) Storage Temperature ESD Human Body Model ESD Charged Device Model ESD Machine Model Rating −0.3 V to +6 V −0.3 V to +0.3 V −40°C to +85°C −40°C to +125°C JEDEC J-STD-020 ±2000 V ±500 V ±150 V Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. θJA of the package is based on modeling and calculation using a 4-layer board. θJA is highly dependent on the application and board layout. In applications where high maximum power dissipation exists, attention to thermal board design is required. The value of θJA may vary, depending on PCB material, layout, and environmental conditions. The specified value of θJA is based on a 4-layer, 4 in × 3 in, 2 ½ oz copper board, per JEDEC standards. For more information, see the AN-617 Application Note, MicroCSP™ Wafer Level Chip Scale Package. θJA is specified for a device mounted on a JEDEC 2S2P PCB. Table 5. Thermal Resistance Package Type 12-Ball WLCSP 10-Lead LFCSP ESD CAUTION THERMAL DATA The ADP1650 may be damaged if the junction temperature limits are exceeded. Monitoring TA does not guarantee that TJ is within the specified temperature limits. In applications with high power dissipation and poor thermal resistance, the maximum TA may have to be derated. In applications with moderate power dissipation and low PCB thermal resistance, the maximum TA can exceed the maximum limit as long as the TJ is within specification limits. TJ of the device is dependent on the TA, the power dissipation (PD) of the device, and the junction-to-ambient thermal resistance (θJA) of the package. Maximum TJ is calculated from the TA and PD using the following formula: TJ = TA + (PD × θJA) Rev. C | Page 6 of 32 θJA 75 42.5 Unit °C/W °C/W ADP1650 PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS BALL A1 INDICATOR 1 2 3 PGND SGND VIN SW GPIO2 GPIO1 VOUT STROBE EN A B VIN 1 GPIO2 2 GPIO1 3 LED_OUT SDA SDA 4 SCL SCL 5 D ADP1650 TOP VIEW 9 EN 8 SW 7 VOUT 6 LED_OUT NOTES 1. THE EXPOSED PADDLE MUST BE CONNECTED TO GROUND. 08837-004 TOP VIEW (BALL SIDE DOWN) Not to Scale 10 STROBE Figure 4. WLCSP Pin Configuration 08837-070 C Figure 5. LFCSP Pin Configuration Table 6. Pin Function Descriptions WLCSP A1 A2 A3 B1 B2 Pin No. LFCSP N/A 1 N/A1 1 8 2 Mnemonic PGND SGND VIN SW GPIO2 B3 3 GPIO1 C1 7 VOUT C2 10 STROBE C3 9 EN D1 D2 D3 6 4 5 0 LED_OUT SDA SCL EPAD 1 Description Power Ground. Signal Ground. Input Voltage for the Device. Connect an input bypass capacitor close to this pin. Boost Switch. Connect the power inductor between SW and the input capacitor. ILED/TX2/ADC. Mode is register selectable. Red indicator LED current source or TxMASK2 or ADC input. ILED Mode. Connect to red LED anode. Connect the LED cathode to power ground. TxMASK2 Mode. Reduces the current to the programmable TxMASK2 current. ADC Mode. This pin is used as the input pin for the ADC. Torch/TX1. Mode is register selectable. External torch mode or TxMASK1 input. Torch Mode. Enables the integrated circuit (IC) in direct torch mode. TxMASK1 Mode. Reduces the flash current to the programmable TxMASK1 current. Boost Output. Connect an output bypass capacitor very close to this pin. This is the output for the 5 V external voltage mode. Strobe Signal Input. This pin synchronizes the flash pulse to the image capture. In most cases, this signal comes directly from the image sensor. Enable. Set EN low to bring the quiescent current (IQ) to <1 μA. Registers are set to their defaults when EN is brought from low to high. LED Current Source. Connect this pin to the anode of the flash LED. I2C Data Signal in I2C Mode. I2C Clock Signal in I2C Mode. Exposed Pad. Connect the exposed pad to the ground plane for the LFCSP version. N/A means not applicable. Rev. C | Page 7 of 32 ADP1650 TYPICAL PERFORMANCE CHARACTERISTICS IL = inductor current, ILED = LED current, LED_OUT = LED output, IBAT = battery current. IL ILED 4 LED_OUT 3 SW 4 ILED 2 IL CH2 1A Ω CH4 500mA Ω 1 M100µs A CH1 T 402.2µs 400mV 08837-025 CH1 5V CH3 1V 08837-031 2 STROBE 1 CH1 2V CH2 100mA Ω CH4 25mA Ω M100ns A CH1 T 4.16007ms 1.6V Figure 9. Switching Waveforms, Flash Mode, ILED = 1500 mA Figure 6. Startup Flash Mode, VIN = 3.6 V, ILED = 1500 mA VIN LED_OUT LED_OUT 3 3 ILED 4 IL IL ILED CH1 5V CH3 2V CH2 100mA Ω CH4 100mA Ω M1.00ms A CH1 T 4.16ms 08837-032 GPIO1 (Torch) 1 2 08837-026 2 1 4 600mV CH1 5V CH3 2V Figure 7. Startup Torch Mode, VIN = 3.6 V, ILED = 100 mA CH2 100mA Ω CH4 100mA Ω M1ms T 30.40% A CH2 88mA Figure 10. Pass-Through to Boost Mode Transition, ILED = 100 mA VIN = 3.6V LED_OUT LED_OUT IBAT 3 3 ILED 4 ILED 4 GPIO1 (TxMASK1) STR CH1 2V CH3 1V CH2 1A Ω CH4 500mA Ω M100µs A CH1 T 394.6µs 08837-035 1 08837-028 2 2 IL 1 CH1 2V CH3 1V 440mV Figure 8. 100 mA Torch to 1500 mA Flash Transition CH2 1A Ω CH4 500mA Ω M10µs T 30.60% A CH1 Figure 11. Entry into TxMASK1 Mode Rev. C | Page 8 of 32 680mV ADP1650 100 90 LED_OUT 80 EFFICIENCY (%) 70 IBAT 2 ILED 40 30 08837-036 20 1 CH2 2V CH4 1V CH2 1A Ω CH4 500mA Ω M40µs T 16% A CH1 0 0.3 680mV 100 –40°C +25°C +85°C +125°C 3.03 3.02 80 EFFICIENCY (%) 3.00 2.99 2.98 1.3 1.5 60 50 40 2.97 30 2.96 20 2.95 10 3.0 3.3 3.6 3.9 4.2 4.5 4.8 5.1 5.4 0 0.01 08837-038 0.1 1 OUTPUT CURRENT (A) Figure 16. Voltage Regulation Mode Efficiency vs. Load Current Figure 13. Switching Frequency vs. Supply Voltage (3 MHz Mode) 1111 VIN = 2.7V VIN = 3.6V VIN = 4.5V 1110 ADC RESULT (Binary) 1100 4 3 2 1010 1000 0110 0100 1 0000 –20 0 20 40 60 80 100 TEMPERATURE (°C) 120 08837-043 0 –40 0010 0 50 100 150 200 250 300 350 400 450 500 550 ADC INPUT VOLTAGE (mV) Figure 17. ADC External Voltage Mode Transfer Characteristic Figure 14. Standby Current vs. Temperature Rev. C | Page 9 of 32 08837-059 fSW (MHz) 1.1 70 INPUT VOLTAGE (V) STANDBY CURRENT (µA) 0.9 VIN = 2.7V VIN = 3.0V VIN = 3.6V VIN = 4.2V 90 3.01 5 0.7 Figure 15. Flash Mode Efficiency vs. LED Current 3.04 6 0.5 LED CURRENT (A) Figure 12. Exit from TxMASK1 Mode 2.94 2.7 VIN = 4.2V VIN = 3.6V VIN = 3.4V VIN = 3.2V 10 08837-044 GPIO1 (TxMASK1) 4 50 08837-045 3 60 ADP1650 295 1111 293 CODE 1000 MIDPOINT (mV) 1010 1000 0110 0100 292 291 290 VIN = 3.6V 289 288 0010 50 75 100 125 150 Figure 18. ADC Die Temperature Mode Transfer Characteristic 10 60 110 TEMPERATURE (°C) Figure 21. ADC External Voltage Mode, Code 1000, Midpoint vs. Temperature 1111 1.0 1110 0.5 LED CURRENT ERROR (%) 1100 ADC RESULT (Binary) 286 –40 08837-063 25 08837-060 0 DIE TEMPERATURE (°C) 1010 1000 0110 0100 VIN = 3.2V VIN = 3.6V VIN = 4.2V 0 –0.5 –1.0 –1.5 –2.0 0010 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 –2.5 –40 08837-061 0000 2.8 LED_OUT VOLTAGE (V) 0.5 VIN = 5.0V 0 LED CURRENT ERROR (%) 3.750 3.745 3.740 VIN = 3.6V 3.735 3.730 VIN = 2.7V 3.725 60 110 Figure 22. LED Current Accuracy vs. Temperature, ILED = 1200 mA 3.760 3.755 10 TEMPERATURE (°C) Figure 19. ADC LED VF Mode Transfer Characteristic CODE 1000 MIDPOINT (V) VIN = 2.7V 287 08837-066 ADC RESULT (Binary) 1100 0000 VIN = 5V 294 1110 3.720 VIN = 3.2V VIN = 3.6V VIN = 4.2V –0.5 –1.0 –1.5 –2.0 –2.5 10 60 TEMPERATURE (°C) 110 Figure 20. ADC LED VF Mode, Code 1000, Midpoint vs. Temperature –3.0 –40 10 60 110 TEMPERATURE (°C) Figure 23. LED Current Accuracy vs. Temperature, ILED = 800 mA Rev. C | Page 10 of 32 08837-067 3.710 –40 08837-062 3.715 ADP1650 3.0 2.5 1.0 VIN = 3.2V VIN = 3.6V VIN = 4.2V 0.5 VIN = 3.2V VIN = 3.6V VIN = 4.2V LED CURRENT ERROR (%) 1.5 1.0 0.5 0 –0.5 0 –0.5 –1.0 –1.5 –1.0 –2.0 –40 10 60 TEMPERATURE (°C) 110 –2.5 –40 10 60 110 TEMPERATURE (°C) Figure 24. LED Current Error vs. Temperature, ILED = 1500 mA Figure 25. LED Current Error vs. Temperature, ILED = 1000 mA Rev. C | Page 11 of 32 08837-069 –2.0 –1.5 08837-068 LED CURRENT ERROR (%) 2.0 ADP1650 THEORY OF OPERATION The ADP1650 is a high power, I2C programmable white LED driver ideal for driving white LEDs for use as a camera flash. The ADP1650 includes a boost converter and a current regulator suitable for powering one high power white LED. MODES OF OPERATION WHITE LED DRIVER LED_MOD = [00] sets the device in standby mode, consuming 3 μA (typical). Once the enable pin is high, the device can be set into the four modes of operation using the LED_MOD bits in Register 0x04, via the I2C-compatible interface. The ADP1650 drives a synchronous 3 MHz boost converter as required to power the high power LED. If the sum of the LED forward voltage and current regulator voltage is higher than the battery voltage, the boost turns on. If the battery voltage is higher than the sum of the LED VF and current regulator voltage, the boost is disabled and the part operates in pass-through mode. The ADP1650 uses an integrated PFET high-side current regulator for accurate brightness control. LED_MOD = [01] sets the device in fixed VOUT = 5 V output mode. LED_MOD = [10] sets the device in assist light mode with continuous LED current. LED_MOD = [11] sets the device in flash mode with current up to 1.5 A available for up to 1.6 sec. INPUT VOLTAGE = 2.7V TO 5.0V CIN 10µF L1 1µF COUT 10µF PGND PGND VIN VOUT SW 5.5V 2.4V CURRENT SENSE UVLO HPLED DRIVER OVP CURRENT SENSE PWM CONTROLLER LED_OUT EN FAULT REGISTER SCL HPLED SHORT INTERFACE AND CONTROL SDA STROBE TXMASK1 TORCH 25mA TO 1.5A HIGH POWER LED CURRENT CONTROL TXMASK2 VIN 4-BIT ADC PGND IC THERMAL SENSING ILED LED_OUT PIN IO2_CFG[7:6] GPIO1 SGND GPIO2 AGND Figure 26. Detailed Block Diagram Rev. C | Page 12 of 32 PGND PGND 08837-006 IO1_CFG[5:4] ADP1650 I(FLASH) ASSIST LIGHT The assist light provides continuous current programmable from 25 mA to 200 mA. Set the assist light current using the I_TOR bits (in Register 0x03). To enable assist, set LED_MOD to assist light mode and set OUTPUT_EN = 1 (in Register 0x04). Disable assist light mode by setting LED_MOD to standby mode or setting OUTPUT_EN = 0. LED CURRENT 0A FL_TIM STROBE I2C DATA BUS REG 0x02, FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA I(ASSIST) LED CURRENT ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00. 08837-009 REG 0x04, OUTPUT_EN = 1 STR_LV = 0 LED_MOD = 11 0A Figure 29. Flash Operation: Edge-Sensitive Mode I2C DATA BUS REG 0x04, OUTPUT_EN = 0 REG 0x04, OUTPUT_EN = 1 LED_MOD = 10 08837-007 ASSIST-TO-FLASH OPERATION I(FLASH) Figure 27. Enabling Assist Light Mode LED CURRENT I(ASSIST) FLASH MODE Flash mode provides 300 mA to 1.5 A for a programmable time of up to 1.6 seconds. Set the flash current using the I_FL bits (in Register 0x03) and the maximum flash duration with the FL_TIM bits (in Register 0x02). To enable flash mode, set LED_MOD to flash mode and set OUTPUT_EN = 1. Enable flash without STROBE by setting STR_MODE (in Register 0x04) to 0 (software strobe). When STR_MODE is in hardware strobe mode, setting the STROBE pin high enables flash and synchronizes it to the image sensor. Hardware strobe mode has two modes for timeout: level sensitive and edge sensitive. I(FLASH) 0A STROBE I2C D ATA BUS REG 0x02, FL_TIM = XXXX ms REG 0x03, I_TOR = XXX mA REG 0x03, I_FL = XXXXX mA ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00. REG 0x04, OUTPUT_EN = 1 STR_LV = 1 LED_MOD = 10 08837-010 REG 0x03, I_TOR = XXX mA In edge-sensitive mode, a positive edge on the STROBE pin enables the flash, and the FL_TIM bits set the flash duration. Figure 30. Enabling Assist to Flash (Level-Sensitive) Mode The STR_POL bit in Register 0x07 changes the default enable of STROBE from low to high to high to low. Additional image sensor-specific assist/flash enable modes are included in the device, and information on these is available on request from the Analog Devices, Inc., sales team. LED CURRENT 0A STROBE TORCH MODE I2C DATA BUS ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00. 08837-008 REG 0x04, OUTPUT_EN = 1 STR_LV = 1 LED_MOD = 11 Figure 28. Flash Operation: Level-Sensitive Mode In level-sensitive mode, the duration of STROBE high sets the duration of the flash up to the maximum time set by the FL_TIM timeout. If STROBE is kept high longer than the duration set by FL_TIM, a timeout fault disables the flash. I(ASSIST) LED CURRENT 0A GPIO1 (TORCH) I2C DATA BUS REG 0x03, I_TOR = XXX mA ADP1650 SETS OUTPUT_EN TO 0 REG 0x04, OUTPUT_EN = 1 LED_MOD = 00 Figure 31. Enabling External Torch Mode Using GPIO1 Rev. C | Page 13 of 32 08837-065 REG 0x02, FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA Set the assist/torch light current using the I_TOR bits. To enable torch mode using a logic signal, set LED_MOD to standby mode and OUTPUT_EN = 1, and then bring GPIO1 high. Disable external torch mode by setting GPIO1 low or programming OUTPUT_EN = 0. Bringing GPIO1 low during torch mode automatically sets OUTPUT_EN = 0. To enable torch mode again, program OUTPUT_EN = 1, and bring GPIO high again. ADP1650 TORCH-TO-FLASH MODE FREQUENCY FOLDBACK The driver can move directly from external torch mode (using GPIO1) to flash mode by bringing STROBE high before GPIO1 = torch is brought low. Bringing torch low before STROBE goes high prevents the flash from firing when STROBE goes high. Frequency foldback is an optional mode that optimizes efficiency by reducing the switching frequency to 1.5 MHz when VIN is slightly less than VOUT. Enable frequency foldback by setting FREQ_FB = 1 in Register 0x04. The ADP1650 returns to standby mode after a successful flash and sets OUTPUT_EN = 0. INDICATOR LED DRIVER The indicator LED driver on GPIO2 provides a programmable current source of between 2.75 mA and 11 mA for driving a red privacy LED. The current level is programmed by the I_ILED bits in Register 0x07. The circuit consists of a programmable current source and a monitoring circuit that uses comparators to determine whether the indicator LED is shorted or open. The threshold for detection of a short is 1.2 V (maximum) and an open circuit is 2.45 V (minimum). The indicator LED must not be used at the same time as a flash or assist/torch event. I(FLASH) LED CURRENT I(ASSIST) 0A STROBE TORCH I2C DATA BUS REG 0x02, FL_TIM = XXXX ms ADP1650 SETS OUTPUT_EN TO 0 IO1_CFG = 01, TORCH REG 0x03, I_TOR = XXX mA REG 0x03, I_FL = XXXXX mA REG 0x04, OUTPUT_EN = 1 STR_LV = 1 LED_MOD = 00 08837-064 LOW BATTERY LED CURRENT FOLDBACK Figure 32. Enabling Flash Mode from External Torch Mode As the battery discharges, the lower battery voltage results in higher peak currents through the battery ESR, which may cause early shutdown of the phone. The ADP1650 features an optional low battery detection option, which reduces the flash current (to a programmable level) when the battery voltage falls below a programmable level. TxMASK OPERATION GLITCH < 50µs IGNORED VIN When the ADP1650 is in flash mode, the TxMASK1 and TxMASK2 functions reduce the battery load in response to the system enabling a power amplifier. The device remains in flash mode, but the LED driver output current reduces to the programmed TxMASK light level in less than 21 μs. 50mV HYS V(V_VB_LO) STROBE I2C D ATA BUS LED CURRENT I(TXMASK1) REG 0x09, I_VB_LO = XXXX mA V_VB_LO = XXX V 0A REG 0x04, OUTPUT_EN = 1 LED_MOD = 10 TXMASK1 (GPIO1) FL_VB_LO = 1 ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00. 08837-012 I(FLASH) Figure 34. Register 0x09 Sets the Battery Voltage Threshold Level and the Reduced LED Current Level STROBE Table 7. VDD Level at Which the VBAT Low Function Is Enabled I2C D ATA BUS Bit Name V_VB_LO FL_TX1 = 1 ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00. REG 0x04, OUTPUT_EN = 1 STR_LV = 1 LED_MOD = 11 08837-011 REG 0x02, IO1_CFG = 10 FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA REG 0x06, I_TX1 = XXXX mA Figure 33. TxMASK1 Operation During Flash (Level-Sensitive) Mode The device selects the TxMASK1 or TxMASK2 current level based on whether the TxMASK1 or TxMASK2 input is used. After a TxMASK1 or TxMASK2 occurs, a flag is set in the fault information register. When the TxMASK signal goes low again, the LED current goes back to the full flash level in a controlled manner to avoid overshoots on the battery current. If both TxMASK inputs are set high simultaneously, the TXMASK1 current level is used. VDD Level 000 = disabled (default) 001 = 3.3 V 010 = 3.35 V 011 = 3.4 V 100 = 3.45 V 101 = 3.5 V 110 = 3.55 V 111 = 3.6 V Set V_VB_LO = 000 to disable the low battery current foldback. Rev. C | Page 14 of 32 ADP1650 PROGRAMMABLE BATTERY DC CURRENT LIMIT ANALOG-TO-DIGITAL CONVERTER OPERATION The ADP1650 has four optional programmable input dc current limits that limit the maximum battery current that can be taken over all conditions. This allows higher LED currents to be used in a system with significant variation in LED forward voltage (VF) and supply battery voltage without risk of the current allocated to the flash being exceeded. The internal 4-bit analog-to-digital converter (ADC) is configurable to measure the LED VF, integrated circuit (IC) die temperature, or an external voltage using the GPIO2 pin. Read the 4-bit resolution output code back from Register 0x08 using the I2C interface. EN Table 8. Input DC Current Limit Setting the LED Current Current Limit 00 = 1.5 A 01 = 1.75 A 10 = 2.0 A (default) 11 = 2.25 A IC TEMPERATURE SENSOR SDA SCL During startup of the flash, if the battery current does not reach the dc current limit, the LED current is set to the current value of the I_FL bits. If the battery current does hit the programmed dc current limit on startup, the LED current does not increase further. The dc current limit flag is set in the fault information register. The I_FL bits in Register 0x03 are set to the actual LED current and are available for readback. NO LIMIT LED CURRENT ACTUAL LED CURRENT STROBE I2C DATA BUS ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00. ADP1650 SETS FL_IDC (REG 0x05) TO 1. ADP1650 SETS I_FL TO ACTUAL LED CURRENT. 08837-013 REG 0x02, FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA IL_DC_EN = 1 IL_DC = XX A REG 0x04, OUTPUT_EN = 1 STR_LV = 1 LED_MOD = 11 PTC Figure 37. Available ADC Modes in the ADP1650 The ADC can perform the conversion either immediately on an I2C command, or it can delay the conversion until the next time the ADP1650 exits an active mode. Delayed conversion can be useful, for example, for measuring the IC temperature at the end of a timed flash period. To set up a delayed conversion, set ADC_EN to the required mode while OUTPUT_EN = 0. Then set the ADP1650 to the desired output mode (torch, flash assist light, or 5 V output) and set OUTPUT_EN = 1. The ADC conversion is performed when the ADP1650 exits the chosen mode. The ADC can measure the LED VF in both flash and assist/ torch modes. In torch mode, set ADC_EN = 01 to begin a conversion. The value can be read back from the ADC_VAL[5:2] bits 1 ms after the conversion has started. Assist/torch mode, rather than flash mode, is best in the handset production test to verify the LED VF. PREFLASH STROBE STROBE 4-BIT ADC LED VF Mode SELECT FLASH CURRENT SELECT MAX BATTERY CURRENT LED CURRENT = PROGAMMED LED CURRENT ADC_VAL[5:2] Note that an ADC conversion cannot be performed when the ADP1650 is idle. This is interpreted as an attempt to set up a delayed conversion. The camera system shown in Figure 36 can adjust the image sensor settings based on the known reduced LED current for a low battery and a high VF LED. DC LIMIT HIT? LED_OUT ADC_EN[1:0] To perform an immediate conversion, set ADC_EN to the required mode during ADP1650 operation (OUTPUT_EN = 1). Figure 35. DC Current Limit Operation in a Low Battery, High LED VF Case NO GPIO2 INTERFACE/ CONTROL 08837-015 Bit Name IL_DC YES LED CURRENT = REDUCED LED CURRENT 1ms START CONVERSION (INTERNAL SIGNAL) BATTERY CURRENT = PROGRAMMED DC LIMIT I2C READ LED CURRENT 08837-014 STROBE REG 0x08, ADC_EN = 01 Figure 36. Use of the DC Current Limit in an Optimized Camera System ADC_VAL[5:2] AVAILABLE FOR READ 08837-016 I2C DATA BUS ADJUST IMAGE SENSOR Figure 38. ADC Timing for All Modes Except VF Measurement in Flash Mode In flash mode, set ADC_EN = 01. The conversion happens just before the timeout occurs; therefore, the FL_TIM bits set when the ADC sample occurs. This allows the VF to settle from the Rev. C | Page 15 of 32 ADP1650 Write ADC_EN = 10 to begin a die temperature measurement. The value can be read back from the ADC_VAL[5:2] bits 1 ms after the conversion has started. The most stable and accurate value of die temperature is available at the end of the flash pulse. initial peak as the junction temperature of the LED stabilizes. An LED temperature vs. flash time profile for the handset PCB design can be generated during the design phase by varying the FL_TIM bits from the lowest to the highest setting and collecting a VF sample on each flash. External Voltage Mode I(FLASH) The ADC measures the voltage on the GPIO2 pin when the GPIO2 is configured as an ADC input by setting IO2_CFG = 11. One example is using an external temperature-dependent resistor to create a voltage based on the temperature of the flash LED. The EN line can be used for biasing to reduce leakage current when the flash is not being used. LED CURRENT 0A FL_TIM STROBE tS = 1ms START CONVERSION (INTERNAL SIGNAL) 5 V OUTPUT OPERATION The ADP1650 can be used as a 5 V boost to supply up to 500 mA for an audio voltage rail or keypad LED driver voltage. To move into voltage regulation mode, the OUTPUT_EN bit must be set to 0. To enable the 5 V output, set LED_MOD[1:0] = 01, and set OUTPUT_EN = 1. The ADP1650 sets the VOUT pin to 5 V and disconnects VOUT from LED_OUT. The VOUT pin is connected to the SW node when the ADP1650 is not enabled. VOUT should not be connected directly to a positive external voltage source because this causes current to flow from VOUT to the battery. I2C DATA BUS ADC_VAL[5:2] AVAILABLE FOR READ 08837-017 REG 0x08, ADC_EN = 01 Figure 39. ADC Timing for VF Measurement in Flash Mode Die Temperature Mode The ADC measures the IC die temperature and provides the result to the I2C interface. This is useful during the design phase of the flash system to optimize PCB layout for the best thermal design. 3.2 MEGAPIXEL TO 5.0 MEGAPIXEL CMOS IMAGE SENSOR INPUT VOLTAGE = 2.7V TO 5.0V ON OFF 10µF 1.0µH STROBE SW VIN VOUT* GPIO2 10µF APPLICATIONS PROCESSOR I2C BUS POWER-ON RESET EN VDD ADP1650 SCL SDA, SCL VOUT = 5.0V KEYPAD LED DRIVER SDA LED_OUT EN GPIO1 SGND PGND GND *THE VOUT PIN IS CONNECTED TO THE SW NODE WHEN THE ADP1650 IS NOT ENABLED. VOUT SHOULD NOT BE CONNECTED DIRECTLY TO A POSITIVE EXTERNAL VOLTAGE SOURCE BECAUSE THIS WILL CAUSE CURRENT TO FLOW FROM VOUT TO THE BATTERY. Figure 40. ADP1650 Voltage Regulation Mode: LED Driver Application Rev. C | Page 16 of 32 08837-018 REG 0x02, FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA REG 0x04, OUTPUT_EN = 1 STR_LV = 0 LED_MOD = 11 ADP1650 10µF 1.0µH STROBE SW VIN VOUT = 5.0V ±8.5%, IMAX = 500mA VOUT GPIO2 SCL SDA, SCL I2C BUS POWER-ON RESET EN 0.1µF 10µF APPLICATIONS PROCESSOR ADP1650 VDD 47nF AUDIO IN+ SDA LED_OUT IN– 80kΩ AUDIO IN– SSM2315 160kΩ IN+ 80kΩ OUT+ MODULATOR FET (Σ-∆) DRIVER OUT– 47nF EN GPIO1 160kΩ SGND PGND SHUTDOWN SD BIAS INTERNAL OSCILLATOR POP/CLICK SUPPRESSION GND Figure 41. ADP1650 Voltage Regulation Mode: Class-D Audio Application Rev. C | Page 17 of 32 08837-019 3.2 TO 5.0 MEGAPIXEL CMOS IMAGE SENSOR INPUT VOLTAGE = 2.7V TO 5.0V ON OFF ADP1650 SAFETY FEATURES For critical fault conditions, such as output overvoltage, flash timeout, LED output short circuit, and overtemperature conditions, the ADP1650 has built-in protection modes. If a critical fault occurs, OUTPUT_EN (Register 0x04) is set to 0, and the driver shuts down. The appropriate fault bit is set in the fault information register (Register 0x05). The processor can read the fault information register through the I2C interface to determine the nature of the fault condition. When the fault register is read, the corresponding fault bit is cleared. If a noncritical event such as an indicator LED open/short or a TxMASK1 or TxMASK2 event occurs, or the dc current limit or soft inductor current limit is hit, the LED driver continues operating. The corresponding information bits are set in the fault information register until the processor reads them. SHORT-CIRCUIT FAULT When the flash driver is disabled, the high-side current regulator disconnects the dc path between the battery and the LED, protecting the system from an LED short circuit. The LED_OUT pin features short-circuit protection that monitors the LED voltage when the LED driver is enabled. If the LED_OUT pin remains below the short-circuit detection threshold, a short circuit is detected. Bit 6 of the fault information register is set high. The ADP1650 remains disabled until the processor clears the fault register. OVERVOLTAGE FAULT The ADP1650 contains a comparator at the VOUT pin that monitors the voltage between VOUT and GND. If the voltage exceeds 5.5 V (typical), the ADP1650 shuts down. Bit 7 in the fault information register is read back as high. The ADP1650 is disabled until the fault is cleared, ensuring protection against an open circuit. DYNAMIC OVERVOLTAGE MODE (DOVP) Dynamic OVP mode is a programmable feature that limits the VOUT voltage exceeding the OVP level while maintaining as much current as possible through the LED. This mode prevents an overvoltage fault in the case of a much higher than expected LED forward voltage. If the LED forward voltage reduces due to the LED temperature rising, the ADP1650 moves out of DOVP mode and regulates the LED at the programmed current level. Set Bit 7 of Register 0x07 high to enable dynamic OVP mode. OVERTEMPERATURE FAULT If the junction temperature of the ADP1650 rises above 150°C, a thermal protection circuit shuts down the device. Bit 5 of the fault information register is set high. The ADP1650 remains disabled until the processor clears the fault register. INDICATOR LED FAULT The GPIO2 pin features open- and short-circuit protection in the indicator LED mode. If a short or open circuit occurs, Bit 2 of the fault information register is set high. The indicator LED regulator ensures that no damage occurs to the IC during a fault. CURRENT LIMIT The internal switch limits battery current by ensuring that the peak inductor current does not exceed the programmed limit (current limit is set by Bit 6 and Bit 7 in Register 0x04). The default mode of the ADP1650 is soft current limit mode. If the peak inductor current hits the limit, Bit 1 of the fault information register is set, and the inductor and LED current cannot increase further. The ADP1650 continues to operate. If the ADP1650 has soft current limit disabled and the peak inductor current exceeds the limit, the part shuts down and Bit 1 of the fault information register is set high. In this case, ADP1650 remains disabled until the processor clears the fault register. INPUT UNDERVOLTAGE The ADP1650 includes a battery undervoltage lockout circuit. During 5 V or LED operation, if the battery voltage drops below the 2.4 V (typical) input UVLO threshold, the ADP1650 shuts down. A power-on reset circuit resets the registers to their default conditions when the voltage rises above the UVLO rising threshold. SOFT START The ADP1650 has a soft start mode that controls the rate of increase of battery current at startup by digitally controlling the output current ramp. The maximum soft start time is 0.6 ms. RESET USING THE ENABLE (EN) PIN A low-to-high transition on the EN pin resets all registers to their default values. Bringing EN low reduces the IQ to 0.2 μA (typical). CLEARING FAULTS The information bits and faults in Register 0x05 clear automatically when the processor reads the fault register. TIMEOUT FAULT When external strobe mode is enabled (Register 0x04, Bit 2), and strobe is set to level-sensitive mode (Register 0x04, Bit 5), if the strobe pin remains high for longer than the programmed timeout period, the timeout fault bit (Register 0x05, Bit 4) is read back as high. The ADP1650 remains disabled until the processor clears the fault register. Rev. C | Page 18 of 32 ADP1650 I2C INTERFACE Figure 42 illustrates the I2C write sequence to a single register. The subaddress content selects which of the nine ADP1650 registers is written to. The ADP1650 sends an acknowledgment to the master after the 8-bit data byte has been written. Figure 43 shows the I2C read sequence of a single register. The ADP1650 includes an I2C-compatible serial interface for control of the LED current, as well as for readback of system status registers. The I2C chip address is 0x30 (0x60 in write mode and 0x61 in read mode). Additional I2C addresses are available on request. The register definitions are shown in the I2C Register Map section. MASTER STOP 1 0 0 0 0 CHIP ADDRESS 0 0 0 SUBADDRESS 0 ADP1650 RECEIVES DATA S P ADP1650 ACK 1 ADP1650 ACK 0 ADP1650 ACK S T 08837-021 0 = WRITE Figure 42. I2C Single Register Write Sequence SUBADDRESS CHIP ADDRESS Figure 43. I2C Single Register Read Sequence Rev. C | Page 19 of 32 ADP1650 SENDS DATA S P 08837-020 CHIP ADDRESS 1 0 1 1 0 0 0 0 1 0 0 ADP1650 ACK 0 S T 0 0 0 ADP1650 ACK 0 1 1 0 0 0 ADP1650 ACK S T MASTER STOP 1 = READ MASTER ACK 0 = WRITE ADP1650 I2C REGISTER MAP The lowest bit number (0) represents the least significant bit, and the highest bit number (7) represents the most significant bit. Table 9. Design Information Register (Register 0x00) Bit [7:0] R/W R Reset State 00100010 Table 10. VREF and Timer Register (Register 0x02) Bit Name IO2_CFG Bit [7:6] R/W R/W IO1_CFG [5:4] R/W FL_TIM [3:0] R/W Description GPIO2 configuration 00 = high impedance (default) 01 = indicator LED 10 = TxMASK2 operation mode 11 = analog input (to ADC) GPIO1 configuration 00 = high impedance (default) 01 = torch 10 = TxMASK1 operation mode 11 = reserved Flash timer value setting 0000 = 100 ms 0001 = 200 ms 0010 = 300 ms 0011 = 400 ms 0100 = 500 ms 0101 = 600 ms 0110 = 700 ms 0111 = 800 ms 1000 = 900 ms 1001 = 1000 ms 1010 = 1100 ms 1011 = 1200 ms 1100 = 1300 ms 1101 = 1400 ms 1110 = 1500 ms 1111 = 1600 ms (default) Rev. C | Page 20 of 32 ADP1650 Table 11. Current Set Register (Register 0x03) Bit Name I_FL Bit [7:3] R/W R/W I_TOR [2:0] R/W Description Flash current value setting 00000 = 300 mA 00001 = 350 mA 00010 = 400 mA 00011 = 450 mA 00100 = 500 mA 00101 = 550 mA 00110 = 600 mA 00111 = 650 mA 01000 = 700 mA 01001 = 750 mA 01010 = 800 mA 01011 = 850 mA 01100 = 900 mA 01101 = 950 mA 01110 = 1000 mA (default) 01111 = 1050 mA 10000 = 1100 mA 10001 = 1150 mA 10010 = 1200 mA 10011 = 1250 mA 10100 = 1300 mA 10101 = 1350 mA 10110 = 1400 mA 10111 = 1450 mA 11000 = 1500 mA Torch and assist light current value setting 000 = 25 mA 001 = 50 mA 010 = 75 mA 011 = 100 mA (default) 100 = 125 mA 101 = 150 mA 110 = 175 mA 111 = 200 mA Rev. C | Page 21 of 32 ADP1650 Table 12. Output Mode Register (Register 0x04) Bit Name IL_PEAK Bit [7:6] R/W R/W STR_LV 5 R/W FREQ_FB 4 R/W OUTPUT_EN 3 R/W STR_MODE 2 R/W LED_MOD [1:0] R/W Description Inductor peak current limit setting 00 = 1.75 A 01 = 2.25 A 10 = 2.75 A (default) 11 = 3.0 A 0 = edge sensitive 1 = level sensitive (default) 0 = frequency foldback to 1.5 MHz not allowed (default) 1 = frequency foldback to 1.5 MHz allowed 0 = output off (default) 1 = output on 0 = software strobe mode (software flash occurs when output is enabled in flash mode) 1 = hardware strobe mode (the STROBE pin must go high for flash) (default) Configures LED output mode 00 = standby mode (default) 01 = voltage output mode, VOUT = 5 V 10 = assist light mode 11 = flash mode Table 13. Fault Information Register (Register 0x05) Bit Name FL_OVP Bit 7 R/W R FL_SC 6 R FL_OT 5 R FL_TO 4 R FL_TX1 3 R FL_IO2 2 R FL_IL 1 R FL_IDC 0 R Description 0 = no fault (default) 1 = overvoltage fault 0 = no fault (default) 1 = short-circuit fault 0 = no fault (default) 1 = overtemperature fault 0 = no fault (default) 1 = timeout fault 0 = no TxMASK1 operation mode during last flash (default) 1 = TxMASK1 operational mode occurred during last flash If GPIO2 is configured as TxMASK2 0 = no TxMASK2 operations mode during last flash (default) 1 = TxMASK2 operational mode occurred during last flash If GPIO2 is configured as ILED 0 = no fault (default) 1 = indicator LED fault 0 = no fault (default) 1 = inductor peak current limit fault 0 = programmed dc current limit not hit (default) 1 = programmed dc current limit hit Rev. C | Page 22 of 32 ADP1650 Table 14. Input Control Register (Register 0x06) Bit Name I_TX2 Bit [7:4] R/W R/W I_TX1 [3:0] R/W Description TxMASK2 operational mode foldback current 0000 = 100 mA 0001 = 150 mA 0010 = 200 mA 0011 = 250 mA 0100 = 300 mA 0101 = 350 mA 0110 = 400 mA (default) 0111 = 450 mA 1000 = 500 mA 1001 = 550 mA 1010 = 600 mA 1011 = 650 mA 1100 = 700 mA 1101 = 750 mA 1110 = 800 mA 1111 = 850 mA TxMASK1 operational mode foldback current 0000 = 100 mA 0001 = 150 mA 0010 = 200 mA 0011 = 250 mA 0100 = 300 mA 0101 = 350 mA 0110 = 400 mA (default) 0111 = 450 mA 1000 = 500 mA 1001 = 550 mA 1010 = 600 mA 1011 = 650 mA 1100 = 700 mA 1101 = 750 mA 1110 = 800 mA 1111 = 850 mA Rev. C | Page 23 of 32 ADP1650 Table 15. Additional Mode Register, AD_MOD (Register 0x07) Bit Name DYN_OVP Bit 7 R/W R/W SW_LO 6 R/W STR_POL 5 R/W I_ILED [4:3] R/W IL_DC [2:1] R/W IL_DC_EN 0 R/W Description Dynamic OVP 0 = dynamic OVP off (default) 1 = dynamic OVP on Force 1.5 MHz switching frequency 0 = disabled (default) 1 = enabled Strobe polarity 0 = active low 1 = active high (default) Indicator LED current 00 = 2.75 mA (default) 01 = 5.5 mA 10 = 8.25 mA 11 = 11 mA Input dc current limit setting LED current 00 = 1.5 A 01 = 1.75 A 10 = 2.0 A (default) 11 = 2.25 A Input dc current limit 0 = disabled (default) 1 = enabled Table 16. Additional Mode Register, ADC (Register 0x08) Bit Name Reserved Bit 7 R/W R/W FL_VB_LO 6 R ADC_VAL ADC_EN [5:2] [1:0] R/W R/W Description Test mode 0 = disabled (default) 1 = enabled Programmed VBAT low threshold status; low battery mode must be enabled in Register 0x09 0 = VDD is greater than the VBAT low threshold (default) 1 = VDD is less than the VBAT low threshold ADC readback value; four bits (see Figure 17, Figure 18, and Figure 19) ADC enable mode 00 = disabled (default) 01 = LED VF measurement 10 = die temperature measurement 11 = external voltage mode Rev. C | Page 24 of 32 ADP1650 Table 17. Battery Low Mode Register (Register 0x09) Bit Name CL_SOFT Bit 7 R/W R/W I_VB_LO [6:3] R V_VB_LO [2:0] R/W Description Soft inductor peak current limit 0 = disabled (ADP1650 is disabled when the inductor peak current limit is hit) 1 = enabled (default) Current setting for VBAT low mode 0000 = 300 mA 0001 = 350 mA 0010 = 400 mA 0011 = 450 mA 0100 = 500 mA 0101 = 550 mA 0110 = 600 mA 0111 = 650 mA 1000 = 700 mA 1001 = 750 mA 1010 = 800 mA (default) 1011 = 850 mA 1100 = 900 mA 1101 = 950 mA 1110 = 1000 mA 1111 = 1050 mA VDD level where VBAT low function is enabled 000 = disabled (default) 001 = 3.3 V 010 = 3.35 V 011 = 3.4 V 100 = 3.45 V 101 = 3.5 V 110 = 3.55 V 111 = 3.6 V Rev. C | Page 25 of 32 ADP1650 APPLICATIONS INFORMATION capacitor, a low ESR capacitor is required. Table 19 provides a list of suggested input capacitors. EXTERNAL COMPONENT SELECTION Selecting the Inductor The ADP1650 boost converter increases the battery voltage to allow driving of one LED, whose voltage drop is higher than the battery voltage plus the current source headroom voltage. This allows the converter to regulate the LED current over the entire battery voltage range and with a wide variation of LED forward voltage. The inductor saturation current should be greater than the sum of the dc input current and half the inductor ripple current. A reduction in the effective inductance due to saturation increases the inductor current ripple. Table 18 provides a list of recommended inductors. Selecting the Input Capacitor The ADP1650 requires an input bypass capacitor to supply transient currents while maintaining constant input and output voltages. The input capacitor carries the input ripple current, allowing the input power source to supply only the dc current. Increased input capacitance reduces the amplitude of the switching frequency ripple on the battery. Due to the dc bias characteristics of ceramic capacitors, a 0603, 6.3 V, X5R/X7R, 10 μF ceramic capacitor is preferable. Higher value input capacitors help to reduce the input voltage ripple and improve transient response. Selecting the Output Capacitor The output capacitor maintains the output voltage and supplies the LED current during the NFET power switch on period. It also stabilizes the loop. The recommended capacitor is a 10 μF, 6.3 V, X5R/X7R ceramic capacitor. Note that dc bias characterization data is available from capacitor manufacturers and should be taken into account when selecting input and output capacitors. The 6.3 V capacitors are best for most designs. Table 20 provides a list of recommended output capacitors. Higher output capacitor values reduce the output voltage ripple and improve load transient response. When choosing this value, it is also important to account for the loss of capacitance due to output voltage dc bias. Ceramic capacitors have a variety of dielectrics, each with different behavior over temperature and applied voltage. Capacitors must have a dielectric that ensures the minimum capacitance over the necessary temperature range and dc bias conditions. X5R or X7R dielectrics with a voltage rating of 6.3 V or 10 V are recommended for best performance. Y5V and Z5U dielectrics are not recommended for use with any dc-to-dc converter because of their poor temperature and dc bias characteristics. To minimize supply noise, place the input capacitor as close to the VIN pin of the ADP1650 as possible. As with the output Table 18. Suggested Inductors Vendor Toko Toko Coilcraft Murata FDK Value (μH) 1.0 1.0 1.0 1.0 1.0 Part No. FDSD0312 DFE2520 XFL3010 LQM32P_G0 MIPS3226D DCR (mΩ) 41.5 50 43 60 40 ISAT (A) 4.5 3.4 2.4 3 3 Part No. GRM188R60J106ME47 C1608JB0J106K JMK107BJ106MA Dimensions L × W × H (mm) 1.6 × 0.8 × 0.8 1.6 × 0.8 × 0.8 1.6 × 0.8 × 0.8 Part No. GRM188R60J106ME47 C1608JB0J106K JMK107BJ106MA Dimensions L × W × H (mm) 1.6 × 0.8 × 0.8 1.6 × 0.8 × 0.8 1.6 × 0.8 × 0.8 Table 19. Suggested Input Capacitors Vendor Murata TDK Taiyo Yuden Value 10 μF, 6.3 V 10 μF, 6.3 V 10 μF, 6.3 V Table 20. Suggested Output Capacitors Vendor Murata TDK Taiyo Yuden Value 10 μF, 6.3 V 10 μF, 6.3 V 10 μF, 6.3 V Rev. C | Page 26 of 32 Dimensions L × W × H (mm) 3.0 × 3.0 × 1.2 2.5 × 2.0 × 1.2 3.0 × 3.0 × 1.0 3.2 × 2.5 × 1.0 2.5 × 2.0 × 1.2 ADP1650 CEFF = COUT × (1 − TEMPCO) × (1 − TOL) where: CEFF is the effective capacitance at the operating voltage. TEMPCO is the worst-case capacitor temperature coefficient. TOL is the worst-case component tolerance. TEMPCO from −40°C to +85°C is 15%. TOL is 10%. COUT at VOUT (MAX) = 5 V, is 3 μF, as shown in Figure 44. 0 –10 –20 –30 –40 –50 –60 –70 –80 –90 0 1.26 2.52 3.78 5.04 DC BIAS VOLTAGE (V) 6.30 08837-022 In this example, the 10 μF X5R capacitor has the following characteristics: 10 CAPACITANCE CHANGE (%) The worst-case capacitance accounting for capacitor variation over temperature, component tolerance, and voltage is calculated using the following equation: Figure 44. DC Bias Characteristic of a 3 × 6.3 V, 10 μF Ceramic Capacitor Substituting these values in the equation yields CEFF = 3 μF × (1 − 0.15) × (1 − 0.1) = 2.29 μF The effective capacitance needed for stability, which includes temperature and dc bias effects, is 3.0 μF. Rev. C | Page 27 of 32 ADP1650 PCB LAYOUT Poor layout can affect performance, causing electromagnetic interference (EMI) and electromagnetic compatibility (EMC) problems, ground bounce, and power losses. Poor layout can also affect regulation and stability. Figure 45 shows optimized layouts implemented using the following guidelines: • • • • C1 Li-ION + L1 PGND Li-ION + C2 INDUCTOR DIGITAL INPUT/ OUTPUT AREA = 16.4mm 2 LED ANODE 08837-023 • Place the inductor, input capacitor, and output capacitor close to the IC using short tracks. These components carry high switching frequencies and large currents. Route the trace from the inductor to the SW pin with as wide a trace as possible. The easiest path is through the center of the output capacitor. Route the LED_OUT path away from the inductor and SW node to minimize noise and magnetic interference. Figure 45. Layout of the ADP1650 Driving a High Power White LED (WLCSP) Li-ION + L1 C1 PGND VIN STROBE GPIO2 EN GPIO1 SW GND SDA VOUT SCL LED_OUT ADP1650 PGND INDUCTOR C2 VOUT 08837-024 • • Maximize the size of ground metal on the component side to help with thermal dissipation. Use a ground plane with two to three vias connecting to the component side ground near the output capacitor to reduce noise interference on sensitive circuit nodes. With the LFCSP package, six to eight thermal vias connect the ground paddle to the main PCB ground plane. Analog Devices applications engineers can be contacted through the Analog Devices sales team to discuss different layouts based on system design constraints. Figure 46. Example Layout of the ADP1650 Driving a High Power White LED (LFCSP) Rev. C | Page 28 of 32 ADP1650 OUTLINE DIMENSIONS 0.660 0.602 0.544 1.54 1.50 1.46 0.022 REF SEATING PLANE 3 2 1 A BALL A1 IDENTIFIER 2.04 2.00 1.96 0.330 0.310 0.290 B 1.50 REF C D 0.380 0.352 0.324 0.04 MAX COPLANARITY BOTTOM VIEW (BALL SIDE UP) 1.00 REF 0.280 0.250 0.220 020409-B TOP VIEW (BALL SIDE DOWN) 0.50 REF Figure 47. 12-Ball Wafer Level Chip Scale Package [WLCSP] (CB-12-4) Dimensions shown in millimeters 2.48 2.38 2.23 3.10 3.00 SQ 2.90 0.50 BSC 6 1.74 1.64 1.49 EXPOSED PAD 0.50 0.40 0.30 5 TOP VIEW 0.80 0.75 0.70 0.05 MAX 0.02 NOM SEATING PLANE 0.30 0.25 0.20 1 BOTTOM VIEW PIN 1 INDICATOR (R 0.15) FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. 0.20 REF 121009-A PIN 1 INDEX AREA 10 Figure 48. 10-Lead Lead Frame Chip Scale Package [LFCSP_WD] 3 mm × 3 mm Body, Very Very Thin, Dual Lead (CP-10-9) Dimensions shown in millimeters ORDERING GUIDE Model 1 ADP1650ACBZ-R7 ADP1650ACPZ-R7 ADP1650CB-EVALZ ADP1650CP-EVALZ 1 2 Temperature Range −40°C to +125°C −40°C to +125°C Package Description 12-Ball Wafer Level Chip Scale Package [WLCSP] 10-Lead Frame Chip Scale Package [LFCSP_WD] Evaluation Board WLCSP Package Evaluation Board LFCSP Package Z = RoHS Compliant Part. This package option is halide free. Rev. C | Page 29 of 32 Package Option 2 CB-12-4 CP-10-9 Branding LE4 LGX ADP1650 NOTES Rev. C | Page 30 of 32 ADP1650 NOTES Rev. C | Page 31 of 32 ADP1650 NOTES ©2010–2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D08837-0-4/11(C) Rev. C | Page 32 of 32