ADI 公司的ADP1650是集成了I2C兼容接口的1.5A led閃光驅動器.器件集成了1.5MHz或3.0MHz同步電感升壓轉換器,I2C兼容接口和1500mA電流源.火炬模式電流高達200mA,效率大于90%(峰值),主要用在照相手機和智能手機以及數碼相機,攝像機和PDA.本文介紹了ADP1650主要特性,應用電路以及ADP1650 評估板套件主要特性,詳細電路圖和材料清單.

　　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應用:

　　Camera-enabled cellular phones and smart phones

　　Digital still cameras, camcorders, and PDAs

　　圖1.ADP1650功能方框圖

　　ADP1650 評估板

　　The evaluation system is composed of a motherboard, daughter- board and LED sub-board. The motherboard provides the I2C signals from the PC USB port and generates the I/O voltages and digital high and low signals for the daughterboard. For over-temperature measurement, the daughterboard can either be plugged directly into the motherboard or connected to the motherboard via a ribbon cable.

　　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[NT:PAGE=.$]

　　圖2.ADP1650 評估板外形圖

　　圖3.ADP1650 評估板主板電路圖

　　圖4.ADP1650 評估板子板電路圖

　　圖5.ADP1650 LED插板電路圖

　　圖6.ADP1650- EVALZ電路圖

　　評估板材料清單(BOM):

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