1.5 A LED Flash Driver with I2C-CompaTIble Interface
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.
The LED driver maximizes efficiency over the entire battery voltage range to maximize the input-power-to-LED-power 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℃ to +125℃ junction temperature range.
ADP1650主要特性:
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
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
ADP1650应用:
Camera-enabled cellular phones and smart phones
Digital still cameras, camcorders, and PDAs
图1.ADP1650功能方框图
ADP1650 评估板
The motherboard features a 3.3 V regulator and 2.8 V/1.8 V regulators for VDDIO. The daughterboard contains jumpers and test points for easy evaluation of the flash driver IC.
The ADP1650-EVALZ kit includes:
Cables: power (red/black), USB, 2× current measurements
Samples: five ADP1650 devices, two FDSD3012 inductors
LED boards: OSRAM LUWF65N, LumiLEDs PWF-4
图2.ADP1650 评估板外形图
图3.ADP1650 评估板主板电路图
图4.ADP1650 评估板子板电路图
图5.ADP1650 LED插板电路图
图6.ADP1650- EVALZ电路图
评估板材料清单(BOM):
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