AATIAN48 SIGE | Alldatasheet

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AAT2805 EVAL: Dual High Efficiency Charge Pump For White LED and Flash Applications Introduction The AAT2805 EVAL board demonstrates the functionality of the AAT2805 and its application as a white LED backlight driver with flash capability. The backlighting section of the AAT2805 uses a low-noise, constant fre- quency charge pump DC/DC converter with tri-mode load switch (1X), fractional (1.5X) and doubling (2X) con- version to maximize efficiency and operate over a wide input voltage range. Dedicated to the flash section is a low-noise, constant frequency doubling (2X) charge pump that is capable of delivering 300mA of pulsed current. The backlighting section is programmable with the AS 2Cwire™ (Advanced Simple Serial Control™) serial inter- face and is capable of driving up to four independent LED channels. LED constant current levels are set from a 16-level logarithmic scale, and four additional low current settings are available down to 50µA. This document describes the evaluation board and its accompanying user interface. In addition, a brief Getting Started section is included to help the user begin operating the evaluation board. A schematic of the complete circuit is shown in Figure 1, and the actual board layout is given in Figures 2 and 3. For additional informa- tion, please consult the AAT2805 product datasheet. Schematic Figure 1: Evaluation Board Schematic. VDD GP5 GP4 GP34 GP2 5 GP1 GP0 VSS PIC12F675 1µF 1µF C21µF 1µF 10µF 1kΩ 1kΩ 1kΩ 330Ω FLASH SW1 MOVIE SW2 RED LED712 34 5 LIGHT SW3 DC+ DC- MV LT FL D3 D4D1 D2 AAT9513 20Ω 1µF Flash LED EN3 C3- C3+ VOUT_FL VIN D1 GND EN/SET C1+ C1- VOUT_BL C2+ C2- EN_FL AAT2805 GND 1µF GND GND GND GND GND GND DC+ GND GND JPx EV-115.2005.06.1.0 1

In most cases, the board ships mounted onto a battery pack. The battery pack holds three AAA size, conven- tional alkaline batteries. A jumper is inline with the battery supply for connecting/disconnecting power. There are three other jumpers labeled LT, MV, and FL. They provide access to EN/SET, EN_FL, and EN3, respec- tively. To apply power to the board, connect the supply by jumpering ON, MCU. The red LED7 should illumi- nate, indicating that power has been connected. Ensure that LT, MV, and FL are jumpered so that the micro- controller can control the parts. The user interface is provided by three buttons. The buttons are LIGHT, MOVIE, and FLASH. The modes of operation are detailed in Table 1. Each button handles a particular function. The LIGHT button controls the backlight section. When the LIGHT button is held down, the MCU will auto-cycle through the available bright- ness level settings after a short delay. The MOVIE button toggles on/off the movie mode illumination. The FLASH button provides a flash pulse and a red-eye reduction function. When the FLASH button is held down, red-eye reduction mode will be entered after a short delay. Table 1: User Interface Functionality. Button(s) Pushed1 Description LIGHT Increment the number of EN/SET edges. Toggles through the available brightness level settings for the backlighting section. If held down, auto-cycle through the set- tings. MOVIE Toggle on/off movie mode illumination. FLASH Press once to produce a ~300ms flash pulse. Hold down to produce a sequence of red-eye reduction pulses. LIGHT + FLASH Decrement the number of EN/SET edges. Toggles through the available brightness level settings for the backlighting section. If held down, auto-cycle through the set- tings. LIGHT + MOVIE Increment the address. Cycles through addresses 1, 2, and 3 (i.e., main/sub, main-only, sub-only). MOVIE + FLASH Switch to the next current level scale. Cycles through the 20mA, 30mA, 15mA, and Low Current scales. LIGHT + MOVIE + FLASH Reset. All enable lines are pulled low. EV-115 AAT2805 EVAL: Dual High Efficiency Charge Pump For White LED and Flash Applications 2 EV-115.2005.06.1.0 1. The + sign indicates that the specified buttons are all pressed and released together.

AAT2805 EVAL Component Listing Table 2: Component Listing. Component Part Number Description Manufacturer U1 AAT2805 Dual High Efficiency Charge Pump for AnalogicTechBacklight and Flash; TDFN44-16 Package U2 AAT9513 65mΩ, N-Channel Power MOSFET; AnalogicTechSC70JW-8 Package U3 PIC12F675 8-Bit CMOS, FLASH-Based µC; Microchip8-Pin PDIP Package D1-D4 LW M673 Mini-TOPLED White LED; SMT Package OSRAM D0 LMFLC4500 Flash White LED; 4-Chip Package Lumimicro R1-R3 Chip Resistor 1k Ω, 5%, 1/4W; 1206 Vishay C1-C6 ECJ-1VB1A105K 1µF, 10V, X5R, 10%; 0603 Panasonic-ECG C7 GRM31CR70J106KA01L 10µF, 6.3V, X7R, 10%; 1206 Murata R4 Chip Resistor 1 Ω, 5%, 1/8W; 0805 Vishay R5 Chip Resistor 20 Ω, 5%, 1/8W; 0805 Vishay R6 Chip Resistor 330 Ω, 5%, 1/4W; 1206 Vishay JP1 Chip Resistor 0 Ω, 5%; 0805 Vishay JPx Chip Resistor 0 Ω, 5%; 0603 Vishay LED7 CMD15-21SRC/TR8 Red LED; 1206 Chicago Miniature Lamp J1, MV, LT, FL PRPN401PAEN Connecting Header, 2mm Sullins Electronics SW1-SW3 PTS645TL50 Switch Tact, SPST, 5mm ITT Industries EV-115 AAT2805 EVAL: Dual High Efficiency Charge Pump For White LED and Flash Applications 4 EV-115.2005.06.1.0 Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech pr oduct. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service wi thout notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of l iability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accorda nce with AnalogicTech’s standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific tes ting of all parameters of each device is not necessarily performed.