EVALUATION BOARD DATA SHEET EV160 Evaluation Board for the AAT1282 2A Driver for High Intensity LED Camera Flash Introduction The AAT1282 EVAL board demonstrates the functionality of the AAT1282 and its application as a high current white LED flash driver. The device provides excellent efficiency for both flash and movie modes. Two LED channels are provided with excellent current matching. By utilizing the two LED channels, better light efficiency can be achieved and delivered for combined drive current of 2000mA (1000mA on each channel). Conversely, one flash LED may be driven with 2000mA by combining the two flash currents sinks to drive a single LED. Through the I2C interface, the AAT1282 can be programmed with different movie mode currents, flash safety timer, individual channel On/Off and flash mode to movie mode ratio. This document describes the evaluation board and its accompanying user interface. In addition, a brief “Getting Started” section which has been included to help the user begin operating the evaluation board. A schematic of the complete circuit is shown in Figures 1 and 2. The actual board layout is also provided in Figures 3 and 4. For additional operation device details and I2C programming information, please consult the AAT1282 product datasheet. Figure 1: AAT1282 Evaluation Board. Getting Started Power and IC Enable Connect an external power source (3.0V-4.2V, typical battery operating range) to the VIN and GND terminals. A jumper labeled JP7 is inline with the VIN terminal; to turn power ON/OFF, place the jumper on JP7 to the “ON” position. The red LED1 should illuminate, indicating that power has been applied to the circuit. There is an additional jumper labeled JP3 that enables the AAT1282. Once the AAT1282 is enabled, the super capacitor will be charged up, and the LEDs are in the off state. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202313A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 28, 2012 1 EVALUATION BOARD DATA SHEET EV160 Evaluation Board for the AAT1282 2A Driver for High Intensity LED Camera Flash Preliminary Board Set-Up LED Drive Current The AAT1282 has been set up and tested to provide 1000mA maximum current for each current sink FLOUTA and FLOUTB. The maximum current sink current is set by R1 and has been set to 80.6kΩ for a maximum LED drive current of 1000mA. For maximum drive current level below 1000mA, R1 may be adjusted to a higher resistance value. Refer to the AAT1282 datasheet for a table of set resistor values to program a desired flash current other than 1000mA. The two current sinks can be operated independently to provide up to 1000mA of LED drive control. The two current sinks may also be connected in parallel to sum the maximum LED drive current up to 2000mA for one flash LED. Flash Timer The maximum flash duration is set by the capacitor C3. The maximum flash time has been set to 600ms using a 47nF ceramic capacitor. C3 may be adjusted to increase or decrease the maximum full current flash time. The approximate flash time can be set by the following capacitor values: C3 C3 C3 C3 = = = = 16nF 31nF 47nF 74nF ≈ ≈ ≈ ≈ 200ms 400ms 600ms 1 sec. Since the time out timer is a function of input voltage, the maximum time out time can vary over the specified 2.7V to 5.5V input voltage range. As input voltage increases, the time out function will decrease. Current and Voltage Measurement The AAT1282 evaluation board has been designed with several jumpers that may be removed to measure system input and LED drive currents. The use of an oscilloscope and current probes are strongly suggested for measuring LED flash current due to the transient nature of this measurement and to reduce measurement errors induced by placing an ammeter in the circuit. • Jumpers JP1 and JP2: LED current measurement point. To measure LED current, remove the 0Ω jumpers and replace with a short loop of wire that is large enough in diameter to connect an oscilloscope current probe. If two current probes are available, the LED flash current for FLOUT1 and FLOUT2 can be observed simultaneously. • Super Capacitor SC1 voltage may be monitored by using an oscilloscope or multimeter. The super cap voltage can be probed at the capacitor positive terminal or on the anode side of either flash LED. • Jumper JP8: Input supply voltage and current can be monitored at JP8. Due to the transient nature of circuit operation, it is suggested to use a current probe to observe the circuit input current. To measure the input current, remove the 0Ω jumper at JP8 and replace with a short wire loop to connect an oscilloscope current probe. The input supply voltage may be probed at JP8 with either an oscilloscope or multimeter. 2 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202313A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 28, 2012 EVALUATION BOARD DATA SHEET EV160 Evaluation Board for the AAT1282 2A Driver for High Intensity LED Camera Flash Jumpers JP1 and JP2: Remove and replace with a short loop of wire to measure LED current with a current probe Jumper JP8: Remove and replace with a short loop of wire to measure input current with a current probe Figure 2: Current and Voltage Measurement Points. I2C Interface and Control JP5 and JP6 allow probing and connection to the two I2C interface data lines, JP5 for SCL and JP6 for SDA. I2C interface data is programmed by the microcontroller U2 and its associated push button function switches SW1, SW2 and SW3. One may bypass the on-board controller and insert externally generated I2C commands by removing the jumpers on JP5 and JP6 and connecting the respective external SCL and SDA signals to the center contacts of JP5 and JP6. Driving Flash LEDs The AAT1282 evaluation board is initially set up to drive two flash LEDs with a maximum 1A current pulse. Since the AAT1282 integrated current sinks operate with independent reference circuits, they may be used separately to drive two flash LEDs or they may be combined to power a single LED with up to 2A of current. To drive a single flash LED with 2A, remove either JP2 or FLOUT2. Place the single flash LED to be driven in the FLOUT1 position on the PCB. Connect the two AAT1282 current sink inputs in parallel by a short jumper wire soldered between the two PCB cathode pads of FLOUT1 and FLOUT2. Remove JP2 Solder in place a jumper wire to connect FLOUT1 and FLOUT2 current sinks in parallel Figure 3: Connecting Current Sinks in Parallel to Drive One Flash LED at High Current Levels. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202313A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 28, 2012 3 EVALUATION BOARD DATA SHEET EV160 Evaluation Board for the AAT1282 2A Driver for High Intensity LED Camera Flash AAT1282 Evaluation Board User Interface Functionality The user interface is provided by four push buttons: MMC, S.T., A/B, and FLEN. Definitions of the switch controls are given in Table 1. A summary of operational modes for each button is outlined in Table 2. Button Description Movie Mode Control (SW1): Sets movie mode current. Each switch closure will incrementally decrease the movie mode current stating at 100% to 0% (off) in 16 steps. Refer to the AAT1282 datasheet for detailed explanations of movie mode operation. Set Safety Time (SW2): Set Flash LED Safety timer. Each switch closure will decrease the flash safety timer in 16 steps. Refer to the AAT1282 datasheet for detailed explanations of movie mode operation. Flash A/B select (SW3): Toggles on/off each LED channel (FLOUT1, FLOUT2 both or Off) for movie / torch mode operation. Manual Flash Enable (SW4): Initiates a flash from movie mode or an off state, it is returned to the off state after the timer is reached or after the FLEN is released. A master system Reset (press SW1, SW2 and SW3 simultaneously) is required manually after each flash. Reset all data to the AAT1282: Pressing and releasing SW1, SW2 and SW3 simultaneously will reset all the registers of the AAT1282 and turn off the LEDs regardless of the present operational mode. MMC S.T. A/B FLEN Reset Table 1: Switch Control Definitions. Button(s) Pushed SW1 (MMC) SW2 (S.T.) SW3 (A/B) SW4 (FLEN) SW1 + SW3 (F/M ratio) SW1 + SW2 + SW3 Description [Push/Release once per step] Movie mode LED current dimming control. Each switch closure will issue an I2C command to increment the data of the Movie Mode Current Register Bits There are 16 steps in this register to step movie mode current from full scale to off. (Refer to the AAT1282 product datasheet for additional information) [Push/Release once] Increases the data in the Flash Safety Timer register bits and sends an I2C command; as a result the Flash LEDs safety timer factor is decreased from the default setting by C3. (Refer to the AAT1282 product datasheet for additional information) [Push/Release once] Movie mode LED on/off control. Increments the data of the Enable Register Bits to select FLOUT1, FLOUT2, both or off. [Push/Release once] Flash enable. Manually enables the AAT1282 boost converter, initiates a single flash pulse, and starts the flash timer. [Push/Release once] Increment the data of Flash to Movie Mode Current Ratio Register Bits, but the Flash to Movie Mode Current Ratio is decreased. (Refer to the AAT1282 product datasheet for additional information) [Push/Release once] Reset all registers to default. Table 2: User Interface Functionality (Interface Between AAT1282 and the Microcontroller.) SCL VOUT SDA FLEN R2 VCC JP1 0 JP2 0 FL 1 FL2 10k Enable U1 1 2 3 JP3 4 5 L1 1µH C1 2.2µF C3 47nF 6 7 CT EN FLEN AGND IN SW PGND RSET FLA FLGND FLB SDA SCL OUT AAT1282 TDFN33-14 SC1 0.55F 13 R12 30.1k 12 3 14 11 R13 30.1k 10 9 + 1 Bal Gnd 2 8 R1 80.6k C2 2.2µF Figure 4: AAT1282 Evaluation Board Schematic. 4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202313A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 28, 2012 EVALUATION BOARD DATA SHEET EV160 Evaluation Board for the AAT1282 2A Driver for High Intensity LED Camera Flash DC - DC + VCC JP7 MCU JP8 0 R5 R6 R7 10K 10K 10K U2 1 Movie Mode Control Safety Timer A / B Control 0 0 0 21 43 5 2 SW 1 3 4 SW 2 C4 1µF VDD GP5 GP4 GP3 VSS GP0 GP1 GP2 8 FLEN 7 5 R4 330 LED 2 GRN SW 3 0 R3 330 6 PIC12F675 21 43 5 R8 10 k 21 43 5 LED 1 RED SW4 JP4 R9 100k 21 43 5 R10 10k R11 10k SCL JP5 FLEN SDA JP6 SCL SDA Figure 5: AAT1282 Evaluation Board Microcontroller Section Schematic. Figure 6: AAT1282 Evaluation Board Top Layer. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202313A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 28, 2012 5 EVALUATION BOARD DATA SHEET EV160 Evaluation Board for the AAT1282 2A Driver for High Intensity LED Camera Flash Figure 7: AAT1282 Evaluation Board Bottom Layer. 6 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202313A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 28, 2012 EVALUATION BOARD DATA SHEET EV160 Evaluation Board for the AAT1282 2A Driver for High Intensity LED Camera Flash AAT1282 Evaluation Board Bill of Materials Component Part Number Description Manufacturer U1 U2 SW1 – SW4 R1 R9 R2, R5 - R8, R10, R11 R3, R4 R12, R13 JP1, JP2, JP8 C1, C2 C3 C4 L1 FL1-FL2 SC1 LED1 LED2 JP3, JP4, JP5, JP6, JP7 AAT1282IWO PIC12F675 PTS645TL50 Chip Resistor Chip Resistor Chip Resistor Chip Resistor Chip Resistor Chip Resistor GRM188R71A225KE15 GRM155R71C473KA01 GRM185R61A105KE36 SD3812 1R0-R * HS206F CMD15-21SRC/TR8 CMD15-21VGC/TR8 PRPN401PAEN High Power 2A Flash Driver; TDFN33-14 package 8-bit CMOS, FLASH-based μC; 8-pin PDIP package Switch Tact, SPST, 5mm 80.6kΩ, 1%, 1/4W; 0402 100kΩ, 1%, 1/4W; 0603 10kΩ, 5%, 1/4W; 0603 330Ω, 5%, 1/4W; 0603 30.1kΩ, 5%, 1/4W; 0805 0Ω, 5% 2.2µF, 10V, X7R, 0603 47nF, 10V, X7R, 0402 1µF, 10V, X5R, 0603 Drum Core, 1µH, 2.69A, 48mΩ 4x4x1.2mm White Flash LED 0.55F, 85mΩ Red LED; 1206 Green LED; 1206 Conn. Header, 2mm zip Skyworks Microchip ITT Industries Vishay Vishay Vishay Vishay Vishay Vishay MuRata MuRata MuRata Cooper Bussmann * CAP XX Chicago Miniature Lamp Chicago Miniature Lamp Sullins Electronics Table 3: AAT1282 Evaluation Board Component Listing. * Lumileds LXCL-PWM1 or LXCL-PWF4, OSRAM LW F65G, or Seoul Semiconductor FCW401ZD based on availability from the manufacturer. Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved. Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. These materials, including the information contained herein, are provided by Skyworks as a service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Skyworks may change its documentation, products, services, specifications or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from any future changes. No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided hereunder, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale. THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES, INCLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the Skyworks products could lead to personal injury, death, physical or environmental damage. Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper use or sale. Customers are responsible for their products and applications using Skyworks products, which may deviate from published specifications as a result of design defects, errors, or operation of products outside of published parameters or design specifications. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters. Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for identification purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202313A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 28, 2012 7