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1.5 A LED Flash Driver with I2C-Compatible Interface ADP1650
FEATURES
Ultracompact solution Small, 2 mm x 1.5 mm, 12-ball WLCSP package Smallest footprint, 1 mm height, 1 H 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 one 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
FUNCTIONAL BLOCK DIAGRAM
INPUT VOLTAGE = 2.7V TO 5.0V 10F 1.0H
TX1/TORCH TX2/ILED/ADC
GPIO1 GPIO2
VIN
SW
VOUT
10F
ADP1650
STROBE SCL SDA EN SGND PGND
08837-001
LED_OUT MAX 1.5A
Figure 1.
C1
Li-ION +
L1 PGND Li-ION +
C2 INDUCTOR
DIGITAL INPUT/ OUTPUT
APPLICATIONS
Camera-enabled cellular phones and smart phones Digital still cameras, camcorders, and PDAs
AREA = 16.4mm 2
08837-002
LED ANODE
Figure 2. PCB Layout
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 3.0 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 H 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
Rev. 0
conversion and 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 comes in a compact 12-ball, 0.5 mm pitch package and operates within specification over the full -40C to +125C junction temperature range.
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 (c)2010 Analog Devices, Inc. All rights reserved.
ADP1650 TABLE OF CONTENTS
Features .............................................................................................. 1 Applications ....................................................................................... 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Recommended Specifications: Input and Output Capacitance and Inductance ............................................................................. 4 I2C-Compatible Interface Timing Specifications ..................... 5 Absolute Maximum Ratings............................................................ 6 Thermal Data ................................................................................ 6 Thermal Resistance ...................................................................... 6 ESD Caution .................................................................................. 6 Pin Configurations and Function Descriptions ........................... 7 Typical Performance Characteristics ............................................. 8 Theory of Operation ...................................................................... 12 White LED Driver ...................................................................... 12 Modes of Operation ................................................................... 12 Assist Light .................................................................................. 13 Flash Mode .................................................................................. 13 Assist to Flash Operation .......................................................... 13 Torch Mode ................................................................................. 13 Torch-to-Flash Mode ................................................................. 14 TxMASK Operation ................................................................... 14 Frequency Foldback ................................................................... 14 Indicator LED Driver ................................................................. 14 Low Battery LED Current Foldback ........................................ 14 Programmable Battery DC Current Limit .............................. 15 Analog-to-Digital Converter Operation ................................. 15 5 V Output Operation ............................................................... 17 Safety Features................................................................................. 18 Short-Circuit Fault ..................................................................... 18 Overvoltage Fault ....................................................................... 18 Dynamic Overvoltage Mode (DOVP)..................................... 18 Timeout Fault.............................................................................. 18 Overtemperature Fault .............................................................. 18 Indicator LED Fault ................................................................... 18 Current Limit .............................................................................. 18 Input Undervoltage .................................................................... 18 Soft Start ...................................................................................... 18 Reset Using the Enable (EN) Pin ............................................. 18 Clearing Faults ............................................................................ 18 I2C Interface ................................................................................ 19 I2C Register Map ............................................................................. 20 Applications Information .............................................................. 26 External Component Selection ................................................ 26 PCB Layout...................................................................................... 28 Outline Dimensions ....................................................................... 29 Ordering Guide .......................................................................... 29
REVISION HISTORY
4/10--Revision 0: Initial Version
Rev. 0 | Page 2 of 32
ADP1650 SPECIFICATIONS
VIN 1 = 3.6 V, TJ = -40C to +125C for minimum/maximum specifications, and TA = 25C for typical specifications, unless otherwise noted. Table 1.
Parameter2 SUPPLY Input Voltage Range Undervoltage Lockout Threshold Undervoltage Lockout Hysteresis Shutdown Current, EN = 0 V Standby Current, EN = 1.8 V Operating Quiescent Current SW Switch Leakage LED DRIVER LED Current Assist Light, Torch Flash LED Current Error Conditions Min 2.7 2.3 50 Typ Max 5.0 2.5 150 1 10 2 0.5 Unit V V mV A A mA A A
VIN falling TJ = -40C to +85C, current into VIN pin, VIN = 2.7 V to 4.5 V TJ = -40C to +85C, current into VIN pin, VIN = 2.7 V to 4.5 V Torch mode, LED current = 100 mA TJ = -40C to +85C, VSW3 = 4.5 V TJ = 25C, VSW 3 = 4.5 V
2.4 100 0.2 3 5.3
LED Current Source Headroom LED_OUT Ramp-Up Time LED_OUT Ramp-Down Time SWITCHING REGULATOR Switching Frequency Minimum Duty Cycle N-FET Resistance P-FET Resistance Voltage Output Mode VOUT Voltage Output Current Line Regulation Load Regulation 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
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 1500mA ILED = 75 mA to 200 mA ILED = 25 mA to 50mA Flash, 1200 mA LED current Torch, 200 mA LED current
25 200 300 1500 -6 -7 -10 -15 290 190 0.6 0.1 +6 +7 +10 +15
mA mA mA mA % % % % mV mV ms ms MHz MHz % % m m
Switching frequency = 3 MHz Switching frequency = 1.5 MHz Switching frequency = 3 MHz Switching frequency = 1.5 MHz
2.8 1.4
3 1.5 14 7 60 50
3.2 1.6
4.575 ILOAD at VOUT = 300 mA
5 0.3 -0.7
5.425 500
V mA %/V %/A
1200 mA LED current 1200 mA LED current 200 mA LED current 200 mA LED current
580 435 380 285
mV mV mV mV
0.54 1.26
Rev. 0 | Page 3 of 32
V V
ADP1650
Parameter2 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 Conditions From torch rising edge to device start Min 7.4 -22 2.45 4 External voltage mode VF mode, TJ = 25C VF Mode, TJ = -40C to +125C External voltage mode 0 1 1 1.5 0. 5 Typ 390 8 Max 8.6 +22 1.2 Unit k ms % V V bits LSB LSB LSB V ms % A A A A % mV A A A A V V
Input Voltage Range, GPIO2 SAFETY FEATURES Maximum Timeout For Flash Timer Accuracy DC Current Limit
0 1600
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
1.5 1.75 2.0 2.25
+7.0 1.65 1.95 2.2 2.5 3.2
Low VBAT Mode Transition Voltage Error Hysteresis Coil Peak Current Limit
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 2 3
1.55 2.02 2.47 2.7 5.15
50 1.75 2.25 2.75 3.0 5.5 1.2
1.95 2.5 3.0 3.3 5.9 1.3
150 140
C C
VIN is the input voltage to the circuit. All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC). VSW is the voltage on the SW switch pin.
RECOMMENDED SPECIFICATIONS: INPUT AND OUTPUT CAPACITANCE AND INDUCTANCE
Table 2.
Parameter CAPACITANCE Input Output MINIMUM AND MAXIMUM INDUCTANCE Symbol CMIN Conditions TA = -40C to +125C TA = -40C to +125C TA = -40C to +125C Min 4.0 3.0 0.6 Typ 10 10 1.0 Max Unit F F H
L
20 1.5
Rev. 0 | Page 4 of 32
ADP1650
I2C-COMPATIBLE INTERFACE TIMING SPECIFICATIONS
Table 3.
Parameter1 fSCL tHIGH tLOW tSU, DAT tHD, DAT tSU, STA tHD, STA tBUF tSU, STO tR tF tSP CB2
1 2
Min 0.6 1.3 100 0 0.6 0.6 1.3 0.6 20 + 0.1 CB2 20 + 0.1 CB2 0
Max 400
0.9
300 300 50 400
Unit kHz s s ns s s s s s ns ns ns pF
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
SCL
tR
tSU, DAT
tF
tF
tHD, STA
tSP
tR
tBUF
S
tHD, DAT
tHIGH
tSU, STA
Sr
tSU, STO
P
S
08837-003
S = START CONDITION Sr = REPEATED START CONDITION P = STOP CONDITION
Figure 3. I2C-Compatible Interface Timing Diagram
Rev. 0 | Page 5 of 32
ADP1650 ABSOLUTE MAXIMUM RATINGS
Table 4.
Parameter VIN, SDA, SCL, EN, GPIO1, GPIO2, STROBE, LED_OUT, SW, VOUT to GND 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 -40C to +85C -40C to +125C JEDEC J-STD-020 2000 V 500 V 150 V
THERMAL RESISTANCE
JA of the package is based on modeling and calculation using a 4-layer board. JA 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 JA may vary, depending on PCB material, layout, and environmental conditions. The specified value of JA is based on a 4-layer, 4 in x 3 in, 2 1/2 oz copper board, per JEDEC standards. For more information, see the AN-617 Application Note, MicroCSPTM Wafer Level Chip Scale Package. JA is specified for a device mounted on a JEDEC 2S2P PCB. Table 5. Thermal Resistance
Package Type 12-Ball WLCSP JA 75 Unit C/W
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.
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 (JA) of the package. Maximum TJ is calculated from the TA and PD using the following formula: TJ = TA + (PD x JA)
Rev. 0 | Page 6 of 32
ADP1650 PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
BALL A1 INDICATOR 1 PGND A 2 SGND 3 VIN
SW B
GPIO2
GPIO1
VOUT C
STROBE
EN
LED_OUT D
SDA
SCL
TOP VIEW (BALL SIDE DOWN) Not to Scale
Figure 4. Pin Configuration
Table 6. Pin Function Descriptions
Pin No. A1 A2 A3 B1 B2 Mnemonic PGND SGND VIN SW GPIO2 Description Power Ground. Signal Gound. 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 GND. 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 A. 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.
B3
GPIO1
C1 C2 C3 D1 D2 D3
VOUT STROBE EN LED_OUT SDA SCL
Rev. 0 | Page 7 of 32
08837-004
ADP1650 TYPICAL PERFORMANCE CHARACTERISTICS
IL = inductor current, ILED = LED current, LED OUT = LED output, IBAT = battery current.
IL
ILED
4
LED OUT
3 4 2 1
SW ILED IL
08837-025
STROBE CH1 5V CH3 1V CH2 1A CH4 500mA M100s A CH1 T 402.2s 400mV
1
CH1 2V
CH2 100mA CH4 25mA
M100ns A CH1 T 4.16007ms
1.6V
Figure 4. Startup Flash Mode, VIN = 3.6 V, ILED = 1500 mA
Figure 7. Switching Waveforms, Flash Mode, ILED = 1500 mA
VIN
LED OUT LED OUT
3
3
ILED
4
IL IL
08837-026
1
GPIO1 (Torch) CH1 5V CH3 2V CH2 100mA CH4 100mA M1.00ms A CH1 T 4.16ms 600mV
1 4
CH1 5V CH3 2V
CH2 100mA CH4 100mA
M1ms T 30.40%
A CH2
88mA
Figure 5. Startup Torch Mode, VIN = 3.6 V, ILED = 100 mA
VIN = 3.6V
Figure 8. Pass Through to Boost Mode Transition, ILED = 100 mA
LED OUT
LED OUT
IBAT
3
ILED
3
4
ILED
4 2 1
2
GPIO1 (TxMASK1)
08837-035
IL STR CH1 2V CH3 1V CH2 1A CH4 500mA M100s A CH1 T 394.6s 440mV
08837-028
1
CH1 2V CH3 1V
CH2 1A CH4 500mA
M10s T 30.60%
A CH1
680mV
Figure 6. 100 mA Torch to 1500 mA Flash Transition
Figure 9. Entry into TxMASK Mode
Rev. 0 | Page 8 of 32
08837-032
2
ILED
2
08837-031
2
ADP1650
100
LED OUT
90 80 70
IBAT
2
EFFICIENCY (%)
60 50 40 30 20 VIN = 4.2V VIN = 3.6V VIN = 3.4V VIN = 3.2V 0.5 0.7 0.9 1.1 1.3 1.5
08837-044
08837-059
08837-045
ILED
3
4
GPIO1 (TxMASK1)
08837-036
10 0 0.3
1
CH2 2V CH4 1V
CH2 1A CH4 500mA
M40s T 16%
A CH1
680mV
LED CURRENT (A)
Figure 10. Exit from TxMASK Mode
3.04 3.03 3.02 3.01 -40C +25C +85C +125C
Figure 13. Flash Mode Efficiency vs. LED Current
100 90 80 70 VIN = 2.7V VIN = 3.0V VIN = 3.6V VIN = 4.2V
FSW (MHz)
3.00 2.99 2.98 2.97 2.96 2.95
3.0 3.3 3.6 3.9 4.2 4.5 4.8 5.1 5.4
08837-038
EFFICIENCY (%)
60 50 40 30 20 10 0 0.01 0.1 OUTPUT CURRENT (A) 1
2.94 2.7
INPUT VOLTAGE (V)
Figure 11. Switching Frequency vs. Supply Voltage (3 MHz Mode)
6 2.7V 3.6V 4.5V 5
Figure 14. Voltage Regulation Mode Efficiency vs. Load Current
1110 1100
STANDBY CURRENT (A)
4
ADC RESULT (Binary)
1010 1000 0110 0100
3
2
1
0010 0000
-20
0
20
40
60
80
100
120
08837-043
0 -40
0
50
100
150
200
250
300
350
400
450
500
550
TEMPERATURE (C)
ADC INPUT VOLTAGE (mV)
Figure 12. Standby Current vs. Temperature
Figure 15. ADC External Voltage Mode Transfer Characteristic
Rev. 0 | Page 9 of 32
ADP1650
295
1110
294
VIN = 5V
CODE 1000 MIDPOINT (mV)
1100
293 292 291 290 VIN = 3.6V 289 288 287
ADC RESULT (Binary)
1010 1000 0110 0100 0010 0000
0 25 50 75 100 125 150
VIN = 2.7V
08837-060
10
60
TEMPERATURE (C)
110
DIE TEMPERATURE (C)
Figure 16. ADC Die Temperature Mode Transfer Characteristic
Figure 19. ADC External Voltage Mode, Code 1000 Midpoint vs. Temperature
1.0
VIN = 3.2V VIN = 3.6V VIN = 4.2V
1110
0.5
LED CURRENT ERROR (%)
1100
ADC RESULT (Binary)
0
1010 1000 0110 0100 0010 0000 2.8
-0.5
-1.0 -1.5 -2.0
10
60
TEMPERATURE (C)
110
LED_OUT VOLTAGE (V)
Figure 17. ADC LED VF Mode Transfer Characteristic
3.760 3.755 3.750 VIN = 5.0V
Figure 20. LED Current Accuracy vs. Temperature, ILED = 1200 mA
0.5 0 VIN = 3.2V VIN = 3.6V VIN = 4.2V
LED CURRENT ERROR (%)
CODE 1000 MIDPOINT (V)
-0.5 -1.0 -1.5 -2.0 -2.5 -3.0 -40
3.745 3.740 VIN = 3.6V 3.735 3.730 3.725 3.720 3.715 VIN = 2.7V
10
60
TEMPERATURE (C)
110
08837-062
3.710 -40
10
60
TEMPERATURE (C)
110
Figure 18. ADC LED VF Mode, Code 1000, Midpoint vs. Temperature
Figure 21. LED Current Accuracy vs. Temperature, ILED = 800 mA
Rev. 0 | Page 10 of 32
08837-067
08837-066
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
08837-061
-2.5 -40
08837-063
286 -40
ADP1650
3.0 2.5 2.0 VIN = 3.2V VIN = 3.6V VIN = 4.2V
1.0 0.5
VIN = 3.2V VIN = 3.6V VIN = 4.2V
LED CURRENT ERROR (%)
LED CURRENT ERROR (%)
08837-068
1.5 1.0 0.5 0 -0.5 -1.0
0
-0.5
-1.0
-1.5 -2.0
-1.5
10
60
TEMPERATURE (C)
110
10
60
TEMPERATURE (C)
110
Figure 22. LED Current Accuracy vs. Temperature, ILED = 1500 mA
Figure 23. LED Current Accuracy vs. Temperature, ILED = 1000 mA
Rev. 0 | Page 11 of 32
08837-069
-2.0 -40
-2.5 -40
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
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, using the I2C-compatible interface. LED_MOD = [00] sets the device in standby mode, consuming 3 A (typical). 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.
WHITE LED DRIVER
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 passthrough mode. The ADP1650 uses an integrated PFET high side current regulator for accurate brightness control.
INPUT VOLTAGE = 2.7V TO 5.0V L1 1F VIN
SW
CIN 10F
PGND
COUT 10F PGND VOUT
5.5V 2.4V
UVLO
CURRENT SENSE
HPLED DRIVER
OVP
PWM CONTROLLER EN
SCL
CURRENT SENSE LED_OUT FAULT REGISTER HPLED SHORT
SDA STROBE TORCH
INTERFACE AND CONTROL
TXMASK1 TXMASK2
25mA TO 1.5A HIGH POWER LED CURRENT CONTROL IC THERMAL SENSING
PGND
VIN ILED
4-BIT ADC
IO1_CFG[5:4]
IO2_CFG[7:6]
LED_OUT PIN
AGND
PGND
Figure 24. Detailed Block Diagram
Rev. 0 | Page 12 of 32
08837-006
GPIO1
GPIO2
SGND
PGND
ADP1650
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.
I(ASSIST) LED CURRENT 0A
I(FLASH) LED CURRENT 0A STROBE FL_TIM
I2C DATA BUS REG 0x02, FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA REG 0x04, OUTPUT_EN = 1 STR_LV = 0 LED_MOD = 11 ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00.
08837-009
Figure 27. Flash Operation: Edge-Sensitive Mode
I2C DATA BUS REG 0x03, I_TOR = XXX REG 0x04, OUTPUT_EN = 0
08837-007
In edge-sensitive mode, a positive edge on the STROBE pin enables the flash, and the FL_TIM bits set the flash duration.
REG 0x04, OUTPUT_EN = 1 LED_MOD = 10
ASSIST TO FLASH OPERATION
I(FLASH) LED CURRENT I(ASSIST) 0A STROBE
Figure 25. Enabling Assist Light Mode
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)
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.
08837-010
REG 0x04, OUTPUT_EN = 1 STR_LV = 1 LED_MOD = 10
Figure 28. Enabling Assist to Flash (Level-Sensitive) Mode
LED CURRENT
0A
STROBE
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.
TORCH MODE
I2C DATA BUS REG 0x02, FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA REG 0x04, OUTPUT_EN = 1 STR_LV = 1 LED_MOD = 11 ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00.
08837-008
Figure 26. 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.
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.
Rev. 0 | Page 13 of 32
ADP1650
I(ASSIST) LED CURRENT 0A GPIO1 (TORCH)
I(FLASH) LED CURRENT I(TXMASK1) 0A TXMASK1 (GPIO1)
I2C DATA BUS
STROBE
08837-065
REG 0x03, I_TOR = XXX REG 0x04, OUTPUT_EN = 1 LED_MOD = 00
ADP1650 SETS OUTPUT_EN TO 0
Figure 29. . Enabling External Torch Mode Using GPIO1
I2C D ATA BUS REG 0x02, IO1_CFG = 10 FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA REG 0x06, I_TX1 = XXXX mA
REG 0x04, OUTPUT_EN = 1 STR_LV = 1 LED_MOD = 10
TORCH-TO-FLASH MODE
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. The ADP1650 returns to standby mode after a successful flash and sets OUTPUT_EN = 0.
I(FLASH) LED CURRENT I(ASSIST) 0A STROBE TORCH
FL_TX1 = 1
ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00.
08837-011
Figure 31. TxMASK Operation During Flash (Level-Sensitive) Mode
The device selects the TxMASK1 or TxMASK2 current level based on whether 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.
FREQUENCY FOLDBACK
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.
08837-064
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
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.
Figure 30. . Enabling Flash Mode from External Torch Mode
TXMASK OPERATION
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 s.
LOW BATTERY LED CURRENT FOLDBACK
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.
Rev. 0 | Page 14 of 32
ADP1650
GLITCH < 50s IGNORED
VIN
50mV HYS V(V_VB_LO)
NO LIMIT LED CURRENT ACTUAL LED CURRENT
STROBE
STROBE
I2C DATA BUS REG 0x02, FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA IL_DC_EN = 1 IL_DC = XX A
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
I2C D ATA BUS REG 0x09, I_VB_LO = XXXX mA V_VB_LO = XXX V REG 0x04, OUTPUT_EN = 1 LED_MOD = 10
FL_VB_LO = 1 ADP1650 SETS OUTPUT_EN TO 0. ADP1650 SETS LED_MOD TO 00.
REG 0x04, OUTPUT_EN = 1 STR_LV = 1 LED_MOD = 11
08837-012
Figure 33. DC Current Limit Operation in a Low Battery, High LED VF Case
Figure 32. Register 0x09 Sets the Battery Voltage Threshold Level and the Reduced LED Current Level
The camera system shown in Figure 34 can adjust the image sensor settings based on the known reduced LED current for a low battery and a high VF LED.
SELECT FLASH CURRENT SELECT MAX BATTERY CURRENT
Table 6. VDD Level at Which the VBAT Low Function Is Enabled
Bit Name V_VB_LO 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
PREFLASH STROBE
NO
DC LIMIT HIT?
YES
LED CURRENT = PROGAMMED LED CURRENT
LED CURRENT = REDUCED LED CURRENT
STROBE
BATTERY CURRENT = PROGRAMMED DC LIMIT I2C READ LED CURRENT
Set V_VB_LO = 000 to disable the low battery current foldback. 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. Table 7. Input DC Current Limit Setting the LED Current
Bit Name IL_DC Current Limit 00 = 1.5 A 01 = 1.75 A 10 = 2.0 A (default) 11 = 2.25 A
STROBE
08837-014
PROGRAMMABLE BATTERY DC CURRENT LIMIT
ADJUST IMAGE SENSOR
Figure 34. Use of the DC Current Limit in an Optimized Camera System
ANALOG-TO-DIGITAL CONVERTER OPERATION
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
During startup of the flash, if the battery current does not hit 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.
IC TEMPERATURE SENSOR SDA SCL INTERFACE/ CONTROL ADC_EN[1:0] 4-BIT ADC ADC_VAL[5:2]
GPIO2 LED_OUT
PTC
08837-015
Figure 35. Available ADC Modes in the ADP1650
Rev. 0 | Page 15 of 32
ADP1650
LED VF 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.
1ms
I(FLASH) LED CURRENT 0A STROBE
FL_TIM
START CONVERSION (INTERNAL SIGNAL) I2C DATA BUS REG 0x02, FL_TIM = XXXX ms REG 0x03, I_FL = XXXXX mA REG 0x04, OUTPUT_EN = 1 STR_LV = 0 LED_MOD = 11
tS = 1ms
START CONVERSION (INTERNAL SIGNAL)
ADC_VAL[5:2] AVAILABLE FOR READ REG 0x08, ADC_EN = 01
08837-017
I2C DATA BUS
08837-016
Figure 37. ADC Timing for VF Measurement in Flash Mode
REG 0x08, ADC_EN > 0 ADC_VAL[5:2] AVAILABLE FOR READ
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. 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.
Figure 36. 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 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
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.
Rev. 0 | Page 16 of 32
ADP1650
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 will cause current to flow from VOUT to the battery.
3.2 MEGAPIXEL TO 5.0 MEGAPIXEL CMOS IMAGE SENSOR
ON OFF
INPUT VOLTAGE = 2.7V TO 5.0V 10F 1.0H
STROBE GPIO2 APPLICATIONS PROCESSOR
VIN
SW VOUT = 5.0V VOUT* 10F VDD
SCL SDA, SCL I2C BUS SDA
ADP1650
KEYPAD LED DRIVER LED_OUT
POWER-ON RESET
EN GPIO1 SGND PGND
EN
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 38. ADP1650 Voltage Regulation Mode: LED Driver Application
ON OFF INPUT VOLTAGE = 2.7V TO 5.0V 10F 1.0H
3.2 TO 5.0 MEGAPIXEL CMOS IMAGE SENSOR
STROBE GPIO2 APPLICATIONS PROCESSOR
VIN
SW VOUT = 5.0V 8.5%, IMAX = 500mA VOUT 10F 0.1F VDD 47nF AUDIO IN+ LED_OUT AUDIO IN- 47nF IN+ 80k IN- 80k MODULATOR FET (-) DRIVER 160k 160k
SCL SDA, SCL I2C BUS SDA POWER ON RESET
ADP1650
SSM2315
OUT+ OUT-
EN GPIO1 SGND PGND SHUTDOWN SD BIAS
EN
INTERNAL OSCILLATOR
POP/CLICK SUPPRESSION
08837-019
GND
Figure 39. ADP1650 Voltage Regulation Mode: Class D Audio Application
Rev. 0 | Page 17 of 32
08837-018
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 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.
OVERTEMPERATURE FAULT
If the junction temperature of the ADP1650 rises above 150C, 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.
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.
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.
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.
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.
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.
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 A (typical).
CLEARING FAULTS
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. 0 | Page 18 of 32
ADP1650
I2C INTERFACE
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. Figure 41 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 42 shows the I2C read sequence of a single register. The register definitions are shown in the I2C Register Map section.
MASTER STOP
0
0 = WRITE
S T
0
1
1
0
0
0
0
0
0
0 ADP1650 RECEIVES DATA
S P
ADP1650 ACK
CHIP ADDRESS
ADP1650 ACK
SUBADDRESS
ADP1650 ACK
Figure 40. I2C Single Register Write Sequence
0 = WRITE
S T
1 = READ
0S T 0110000100
MASTER STOP
1 ADP1650 SENDS DATA
S P
011000
000
ADP1650 ACK
ADP1650 ACK
CHIP ADDRESS
SUBADDRESS
CHIP ADDRESS
ADP1650 ACK
MASTER ACK
08837-021
Figure 41. I2C Single Register Read Sequence
Rev. 0 | Page 19 of 32
08837-020
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 8. Design Information Register (Register 0x00)
Bit 7:0 R/W R Reset State 00100010
Table 9. VREF and Timer Register (Register 0x02)
Bit Name IO2_CFG Bit 7:6 R/W 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)
IO1_CFG
5:4
R/W
FL_TIM
3:0
R/W
Rev. 0 | Page 20 of 32
ADP1650
Table 10. Current Set Register (Register 0x03)
Bit Name I_FL Bit 7:3 R/W 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
I_TOR
2:0
R/W
Rev. 0 | Page 21 of 32
ADP1650
Table 11. Output Mode Register (Register 0x04)
Bit Name IL_PEAK Bit 7:6 R/W 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
STR_LV FREQ_FB OUTPUT_EN STR_MODE LED_MOD
5 4 3 2 1:0
R/W R/W R/W R/W R/W
Table 12. Fault Information Register (Fault, Register 0x05)
Bit Name FL_OVP FL_SC FL_OT FL_TO FL_TX1 FL_IO2 Bit 7 6 5 4 3 2 R/W R R R R R 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
FL_IL FL_IDC
1 0
R R
Rev. 0 | Page 22 of 32
ADP1650
Table 13. Input Control Register (Register 0x06)
Bit Name I_TX2 Bit 7:4 R/W 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
I_TX1
3:0
R/W
Rev. 0 | Page 23 of 32
ADP1650
Table 14. Additional Mode Register (AD_MOD, Register 0x07)
Bit Name DYN_OVP Bit 7 R/W 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
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
Table 15. Additional Mode Register, ADC (Register 0x08)
Bit Name Reserved Bit 7 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 16, Figure 17, and Figure 18 ADC enable mode 00 = disabled (default) 01 = LED VF measurement 10 = die temperature measurement 11 = external voltage mode
FL_VB_LO
6
R
ADC_VAL ADC_EN
5:2 1:0
R/W R/W
Rev. 0 | Page 24 of 32
ADP1650
Table 16. Battery Low Mode Register (Register 0x09)
Bit Name CL_SOFT Bit 7 R/W 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
I_VB_LO
6:3
R
V_VB_LO
2:0
R/W
Rev. 0 | Page 25 of 32
ADP1650 APPLICATIONS INFORMATION
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. Table 17. Suggested Inductors
Vendor Toko Toko Coilcraft Murata FDK Value (H) 1.0 1.0 1.0 1.0 1.0 Part No. FDSD0312 DFE2520 XFL3010 LQM32P_G0 MIPS3226D DCR (m) 41.5 50 43 60 40 ISAT (A) 4.5 3.4 2.4 3 3 Dimensions L xW x H (mm) 3.0 x 3.0 x 1.2 2.5 x 2.0 x 1.2 3.0 x 3.0 x 1.0 3.2 x 2.5 x 1.0 2.5 x 2.0 x 1.2
Table 18. Suggested Input Capacitors
Vendor Murata TDK Taiyo Yuden Value 10 F, 6.3 V 10 F, 6.3 V 10 F, 6.3 V Part No. GRM188R60J106ME47 C1608JB0J106K JMK107BJ106MA Dimensions L xW x H (mm) 1.6 x 0.8 x 0.8 1.6 x 0.8 x 0.8 1.6 x 0.8 x 0.8
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 10.0 F, 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. Table 19. Suggested Output Capacitors
Vendor Murata TDK Taiyo Yuden Value 10 F, 6.3 V 10 F, 6.3 V 10 F, 6.3 V Part No. GRM188R60J106ME47 C1608JB0J106K JMK107BJ106MA Dimensions L xW x H (mm) 1.6 x 0.8 x 0.8 1.6 x 0.8 x 0.8 1.6 x 0.8 x 0.8
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 F ceramic capacitor is preferable. Higher value input capacitors help to reduce the input voltage ripple and improve transient response. To minimize supply noise, place the input capacitor as close to the VIN pin of the ADP1650 as possible. As with the output capacitor, a low ESR capacitor is required. Table 19 provides a list of suggested input 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.
Rev. 0 | Page 26 of 32
ADP1650
The worst-case capacitance accounting for capacitor variation over temperature, component tolerance, and voltage is calculated using the following equation: CEFF = COUT x (1 - TEMPCO) x (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. In this example, the 10F X5R capacitor has the following: TEMPCO from -40C to +85C is 15%. TOL is 10%. COUT at VOUT (MAX) = 5 V, is 7 F, as shown in Figure 43.
10 0
CAPACITANCE CHANGE (%)
-10 -20 -30 -40 -50 -60 -70 -80 0 1.26 2.52 3.78 5.04 6.30
08837-022
-90 DC BIAS VOLTAGE (V)
Figure 42. DC Bias Characteristic of a 3 x 6.3 V, 10 F Ceramic Capacitor
Substituting these values in the equation yields CEFF =7 F x (1 - 0.15) x (1 - 0.1) = 5.35 F The effective capacitance needed for stability, which includes temperature and dc bias effects, is 3.0 F.
Rev. 0 | 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 44 shows optimized layouts implemented using the following guidelines: * 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. 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. Analog Devices applications engineers can be contacted through the Analog Devices sales team to discuss different layouts based on system design constraints.
*
*
Li-ION +
C1
L1 PGND Li-ION +
C2 INDUCTOR
DIGITAL INPUT/ OUTPUT
AREA = 16.4mm 2
08837-023
LED ANODE
Figure 43. Layout of the ADP1650 Driving a High Power White LED
Rev. 0 | Page 28 of 32
ADP1650 OUTLINE DIMENSIONS
1.54 1.50 1.46 0.660 0.602 0.544 0.022 REF SEATING PLANE
3 2 1 A
BALL A1 IDENTIFIER
2.04 2.00 1.96
0.330 0.310 0.290
1.50 REF
B C D
TOP VIEW
(BALL SIDE DOWN)
0.380 0.352 0.324
0.04 MAX COPLANARITY 0.280 0.250 0.220
0.50 REF 1.00 REF
BOTTOM VIEW (BALL SIDE UP)
Figure 36. 12-Ball Wafer Level Chip Scale Package [WLCSP] (CB-12-4) Dimensions shown in millimeters
ORDERING GUIDE
Model1 ADP1650ACBZ-R7 ADP1650CB-EVALZ
1 2
Temperature Range -40C to +125C
Package Description 12-Ball Wafer Level Chip Scale Package [WLCSP] Evaluation Board
Package Option CB-12-42
020409-B
Branding LE4
Z= RoHS Compliant Part. This package option is halide free.
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ADP1650 NOTES
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ADP1650 NOTES
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ADP1650 NOTES
I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors).
(c)2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D08837-0-4/10(0)
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