EV-100 AAT3140 EVAL: High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Introduction The AAT3140 EVAL board demonstrates the functionality of the AAT3140 and its application as a white LED backlight driver. The AAT3140 is a lownoise, 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. from a 32-level logarithmic scale. The constant current settings range from 30mA/chnl down to 100µA/chnl. 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. The actual board layout is also provided. For additional information, please consult the AAT3140 product datasheet. The AAT3140 is programmable with the S2Cwire™ (Simple Serial Control™) serial digital interface and is capable of driving up to four independent LED channels. LED constant current levels are set Schematic BT- BT+ BT=3 X (AAA) 3 GND J1 2 1 J_Blk3 R3 1k R2 1k 1 PIC12F675 7 Gp5/Osc1/Clkin GND VR4 GP0/An0 3 21 43 5 6 Gp4/Osc2/An3/ClkOut SW-SPST SW2 4 21 43 5 Gp1/An1/Vref LED7 RED 5 Gp3/MClr/Vpp Gp2/T0Cki/An2/Int GND SW-SPST SW1 0 R5 330 POT1 SW3 0 Vss 2 GND 0 8 U2 Vdd C5 1µF R1 1k 21 43 5 R4 LED0 330 GREEN SW-SPST GND R6 220 GND GND 3 J2 2 1 J_Blk_3 R7 100k U1 GND C3 GND D3 JP31 D2 JP21 D1 JP11 D4 JP41 GND 1µF C2 C1 1µF 1 2 3 4 5 6 1µF C2+ CP C1C1+ D3 D2 C2GND IN EN/SET D1 D4 12 11 10 9 8 7 GND JP51 C4 1µF AAT3140 GND 1. Jumpers may be removed to make current measurements. Figure 1: Evaluation Board Schematic. EV-100.2005.03.1.0 1 EV-100 AAT3140 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. It 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 controls 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 auto-increment 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) Pushed Description CYCLE1 Toggle on/off auto-cycling. Auto-increments EN/SET edges and cycles through the available brightness level settings. UP Increment the number of EN/SET edges. Toggles through the available brightness level settings. If held down, auto-cycle through the settings. DOWN Decrement the number of EN/SET edges. Toggles through the available brightness level settings. If held down, auto-cycle through the settings. CYCLE + UP + DOWN2 Reset. Enable line is pulled low. Table 1: User Interface Functionality. 1. The auto-cycling speed is adjusted with the 10K POT, VR4. Turn clockwise to speed up and counter-clockwise to slow down. 2. The '+' sign indicates that these buttons are all pressed and released together. 2 EV-100.2005.03.1.0 EV-100 AAT3140 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). EV-100.2005.03.1.0 3 EV-100 AAT3140 EVAL: High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications AAT3140 EVAL Component Listing Component Part# Description Manufacturer U1 AAT3140 AnalogicTech U2 D1-D4 JP1-JP5 C1-C4 J1, J2 LED0 LED7 R1 - R3 R4, R5 R6 R7 C5 VR4 SW1 - SW5 PIC12F675 LW M673 Chip Resistor ECJ-2FB1E105K PRPN401PAEN CMD15-21UGC/TR8 CMD15-21SRC/TR8 Chip Resistor Chip Resistor Chip Resistor Chip Resistor ECJ-3YB1E105K EVN-5ESX50B14 PTS645TL50 High Efficiency 1X/1.5X/2X Charge Pump for White LED; TSOPJW-12 Package 8-Bit CMOS, FLASH-Based µC; 8-Pin PDIP Package Mini TOPLED White LED; SMT Package 0Ω, 5%, 1/8W; 0805 1µF, 25V, X5R, 10%; 0805 Con. Header, 2mm Zip Green LED; 1206 Red LED; 1206 1K, 5%, 1/4W; 1206 330, 5%, 1/4W; 1206 220, 5%, 1/4W; 1206 100K, 5%, 1/4W; 1206 1µF, 25V, X7R, 10%; 1206 10K POT; 3mm Squared SMD Switch Tact, SPST, 5mm Microchip OSRAM Vishay Panasonic-ECG Sullins Electronics Chicago Miniature Lamp Chicago Miniature Lamp Vishay Vishay Vishay Vishay Panasonic-ECG Panasonic-ECG ITT Industries Table 2: Component Listing. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. 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 without 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 liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. 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-100.2005.03.1.0