1.5 A LED Flash Driver with
I2C-Compatible Interface
ADP1650
FEATURES
FUNCTIONAL BLOCK DIAGRAM
INPUT VOLTAGE = 2.7V TO 5.0V
Ultracompact solution
Small, 2 mm × 1.5 mm, 12-ball WLCSP 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
10µF
1.0µH
VIN
SW
TX1/TORCH
GPIO1
GPIO2
VOUT
TX2/ILED/ADC
10µF
ADP1650
STROBE
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
LED_OUT
MAX 1.5A
SCL
SDA
EN
SGND
PGND
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
Figure 1.
C1
Li-ION +
L1
I2C-compatible control registers
PGND
External STROBE and torch input pins
2 transmitter mask (TxMASK) inputs
Safety
Thermal overload protection
Inductor fault detection
Li-ION +
C2
INDUCTOR
DIGITAL
INPUT/
OUTPUT
LED short-/open-circuit protection
2
AREA = 16.4mm
APPLICATIONS
LED
ANODE
Camera-enabled cellular phones and smart phones
Digital still cameras, camcorders, and PDAs
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 µH
power inductor, and the current source permits LED cathode
grounding for thermally enhanced, low EMI, and compact
layouts.
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 pro-
grammability 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 −40°C to
+125°C junction temperature range.
The LED driver maximizes efficiency over the entire battery
voltage range to maximize the input-power-to-LED-power
Rev. 0
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