EV-117 AAT3151 EVAL: High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications Introduction The AAT3151 EVAL board demonstrates the functionality of the AAT3151 and its application as a white LED backlight driver. The AAT3151 is a low-noise, constant frequency charge pump DC/DC converter with tri-mode load switch (1X), fractional (1.5X), and doubling (2X) conversion to maximize efficiency and operate over a wide input voltage range. The AAT3151 is programmable with the AS2Cwire™ (Advanced Simple Serial Control™) serial interface 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 information, please consult the AAT3151 product datasheet. Schematic DC+ DC- J1 DC+ JP6 U1 C1 1µF 1 2 3 4 5 6 C3 1µF D4 EN/SET C1+ C1VOUT C2+ D3 D2 D1 GND VIN C2- 12 11 10 9 8 7 JPx C4 1µF AAT3151 C2 1µF D1 GND D2 D3 D4 GND JP5 J2 R6 100kΩ R7 220Ω DC+ GND R3 1kΩ CYCLE 0 2 4 SW3 1 3 5 UP 0 2 4 DOWN 0 2 4 SW2 1 3 5 R2 R1 1kΩ 1kΩ U2 1 2 3 4 VDD GP5 GP4 GP3 VSS GP0 GP1 GP2 VR4 POT 10K 8 7 6 5 PIC12F675 GND R5 330Ω LED7 RED R4 330Ω SW1 1 3 5 C5 10µF GND GND LED0 GRN GND Figure 1: Evaluation Board Schematic. EV-117.2005.06.1.0 1 EV-117 AAT3151 EVAL: High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications Getting Started In most cases, the board ships mounted onto a battery pack. The battery pack holds three AAA size, conventional alkaline batteries. A jumper is inline with the battery supply for connecting/disconnecting power. There is an additional jumper labeled ON SRL OFF, which provides access to EN/SET. For operation, ensure that it is in the ON SRL position. To apply power to the board, connect the supply by jumpering ON, MCU. The red LED7 should illuminate, indicating that power has been connected. The user interface is provided by three buttons: CYCLE, UP and DOWN. The modes of operation are detailed in Table 1. Each button handles a particular function. The CYCLE button toggles on/off auto-cycling. The UP button increments to the next number of EN/SET edges. When the UP button is held down, the MCU will autoincrement through all of the settings after a short delay. Pressing the DOWN button decrements the number of EN/SET edges. When the DOWN button is held, the MCU will auto-decrement through all of the settings. User Interface Functionality Button(s) Pushed1 CYCLE 2 UP DOWN CYCLE + UP UP + DOWN CYCLE + UP + DOWN Description Toggle on/off auto-cycling. Auto-increments EN/SET edges and cycles through the available brightness level settings. 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 settings. 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 settings. Increment the address. Cycles through addresses 1, 2, and 3 (i.e., main/sub, mainonly, sub-only). Switch to the next current level scale. Cycles through the 20mA, 30mA, 15mA, and Low Current scales. Reset. Enable line is pulled low. Table 1: User Interface Functionality. 1. The '+' sign indicates that these buttons are all pressed and released together. 2. The auto-cycling speed is adjusted with the 10K POT, VR4. Turn clockwise to speed up and counter-clockwise to slow down. 2 EV-117.2005.06.1.0 EV-117 AAT3151 EVAL: High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications Printed Circuit Board Figure 2: Top Layer (not to scale). Figure 3: Bottom Layer (not to scale)1. EV-117.2005.06.1.0 3 EV-117 AAT3151 EVAL: High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications AAT3151 EVAL Component Listing Component Part Number U1 AAT3151 U2 PIC12F675 D1-D4 R1-R3 C1-C4 J1, J2 LED0 LED7 C5 R4, R5 R6 R7 JPx JP5, JP6 VR4 SW1-SW3 Description LW M673 Chip Resistor ECJ-1VB1A105K PRPN401PAEN CMD15-21UGC/TR8 CMD15-21SRC/TR8 GRM31CR70J106KA01L Chip Resistor Chip Resistor Chip Resistor Chip Resistor Chip Resistor EVN-5ESX50B14 PTS645TL50 High Efficiency 1X/1.5X/2X Charge Pump for White LED; TDFN33-12 Package 8-Bit CMOS, FLASH-Based µC; 8-Pin PDIP Package Mini-TOPLED White LED; SMT Package 1kΩ, 5%, 1/4W; 1206 1µF, 10V, X5R, 10%; 0603 Connecting Header, 2mm Zip Green LED; 1206 Red LED; 1206 10µF, 6.3V, X7R, 10%; 1206 330Ω, 5%, 1/4W; 1206 100kΩ, 5%, 1/4W; 1206 220Ω, 5%, 1/4W; 1206 0Ω, 5%; 0603 0Ω, 5%; 0805 10K POT; 3mm Squared SMD Switch Tact, SPST, 5mm Manufacturer AnalogicTech Microchip OSRAM Vishay Panasonic-ECG Sullins Electronics Chicago Miniature Lamp Chicago Miniature Lamp Murata Vishay Vishay Vishay Vishay Vishay Panasonic-ECG ITT Industries Table 2: Component Listing. 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Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 4 EV-117.2005.06.1.0