Evaluation Board for the AAT2428 Sixteen-Channel White LED Driver Solutionwith LED Current and Timing Control

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EV9 Evaluation Board for the AAT48 Introduction The AAT48 evaluation board is a hardware platform to evaluate the functions of the AAT48, a 6-channel white LED driver for LED current and timing

1 EV9 Evaluation Board for the AAT48 Introduction The AAT48 evaluation board is a hardware platform to evaluate the functions of the AAT48, a 6-channel white LED driver for LED current and timing control. The AAT48 operates over a 0.8V to 8V range. The LED input voltage range, V LED, is determined by the highest V F (LED Forward Voltage) multiplied by the number of LEDs in a given string. The maximum V LED is limited to 50V. The maximum V LED must be less than 50V to avoid damage to the AAT48 on the demo board. The AAT48 CSFBO and ISCFB outputs provide both a voltage mode (CSFBO) for Skyworks regulators and a current mode (ICSFB) current sense feedback for a third party system power supply. The current sinks are setup in a bank of 4, 8, or 6 current sinks. Each bank is programmable via the SPI interface. Full scale LED current is programmed using an external resistor, R. DOT correction is applied to each bank independently with 8-bit resolution. Both phase delay and grayscale clock (GS Clock) PWM on-time are user programmable with -bit resolution for each current sink bank. Timing and synchronization are determined by externally applied VSYNC and GSCLK signals. The AAT48 also provides an internal GSCLK signal that tracks with the VSYNC signal with a 49 ratio to VSYNC. The AAT48 is available in a small 7mm x 7mm QFN package. More details on the AAT48 may be found in the product datasheet. This document will cover the board schematic, layout guidelines and setup of a few key configuration registers to demonstrate the AAT48 driving LED strings with different brightness levels. Scope shots to show the corresponding relationships between related waveforms are also included. Evaluation Board Pictures Figure : AAT48 Evaluation Board Picture. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

2 EV9 Evaluation Board for the AAT48 Board Schematic AATI USB Module 6 SCLK SCLK 5V 5 SDO SDO V 4 4 P.7 CSB 5 CSB P.6 TP5 FB-I R R.k A R A C D D Diode N448 C.µF A C0 R 6.04k CS CS CS VCC D Red LED TP4 FLT A 49 EP 48 FLT RSET ICSFB S S CS CS CS VSYNC GSCLK SDO SCLK CSB R k R9 R0 R5 R6 R7 R ADDR0 ADDR EN 47 VSYNC 46 GSCLK 45 D SDO SCLK 4 CSB 40 S 9 ADDR0 8 ADDR 7 EN R U AAT48 6 A VCCIO 5 4 VCC N/C VIN N/C CSFBO 0 A VCCIO VCC VIN CSFBO C5 4.7µF 50V C.µF C.µF VSYNC GSCLK VIN EN VCC CSFBI JP VSYNC JP4 GSCLK JP ENABLE JP CSFBI C GSCLK VSYNC C SDA SCL GSCLK VSYNC P. USB Module P.4 4 P.5 5 P.0 6 P. 7 SCLK SDO CSB P. 8 P. 9 P 4 5 P.4 0 Header 5 P.5 P.6 P.7 SCLK SDO CSB 4 P.5 P.4 P. P. P. P.0 P Header 5 CS CS4 CSFBI S S S N/C N/C CS5 4 CS6 5 CS7 6 CS8 7 S 8 S 9 CS9 0 CS0 CS CS CS 4 S CS6 CS5 CS CSFBI CS6 CS5 CS4 A CSB VCC P Header 5X JP5 4 ADDR0 SDO SCLK ADDR0 R4 A C7 GSCLK VSYNC VLED P5 Header P7 4 Header 4 GSCLK VSYNC VLED P6 Header P8 4 Header 4 CS CS CS5 CS7 CS9 CS CS CS5 VLED P Header 0X CS CS4 CS6 CS8 CS0 CS CS4 CS6 VLED TP VLED CS5 CS6 CS7 CS8 CS9 CS0 CS CS CS TP6 TP8 TP9 TP0 TP A VCC VIN CSFBO JP6 4 ADDR TP VIN TP CSFBO ADDR C8 VIN CSFBI P9 Header P Header VIN CSFBO P0 Header P Header Figure : AAT48 Evaluation Board Schematic. Printed Circuit Board Specification Symbol Parameter Min Typ Max Units V IN Input Voltage Range V LED V LED Voltage Range 50 V f VSYNC VSYNC Frequency f GSCLK GSCLK Frequency 04 V SYNC M Hz f SCLK SPI Clock Frequency 5 MHz T A Ambient Temperature Range T J Operating Junction Temperature Range C Table : AAT48 Evaluation Board Specifications. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

3 EV9 Evaluation Board for the AAT48 Getting Started Setup. Connect an input power source (to supply between 0.8V and 8V) between VIN and ground.. If using the Skyworks USB Module, connect the USB Module to USB Module connector on the AAT48 demo board. Otherwise, connect frequency generators to apply between 55Hz to 480Hz to VSYNC and the appropriate frequency to GSCLK, leading edge synchronized to VSYNC. Apply a frequency that has a minimum of 4096 VSYNC frequency on GSCLK. Refer to the AAT48 product datasheet to determine the correct GSCLK frequency for the application operating condition. Connect SPI interface on P.. Apply V LED. If V LED is in closed-loop operation and is applied from a third party SMPS converter, connect the FB-I for current mode to the feedback input of the third party SMPS converter. Calculate the value of resistor R for desired V LED level. If using an Skyworks boost converter, connect the CSFBO to the feedback input of the Skyworks boost converter. 4. Connect JP jumper to ON to enable AAT Set ADDR0 and ADDR jumpers to desired address setting. 6. Connect LED strings to P using information provided in Table. 7. If desired, multiple AAT48 demo boards with different device address settings can be cascaded together to drive more than 6 LED channels as shown in Figure. Pin Description Pin Description Current Sink 9 Current Sink 0 Current Sink Current Sink 4 Current Sink 4 Current Sink 5 Current Sink 5 Current Sink 6 Current Sink 4 6 Current Sink 4 7 Current Sink 5 7 Current Sink 5 8 Current Sink 6 8 Current Sink 6 9 Current Sink 7 9 VLED 0 Current Sink 8 0 VLED Table : P LED Pinout Configuration. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

4 Skyworks Solutions, Inc. Phone [78] 76-000 Fax [78] 76-00 sales@skyworksinc.

4 EVALUATION BOARD DATA SHEET EV9 Evaluation Board for the AAT48 Figure : AAT48 PCB + LED Board Picture. Figure 4: Multiple AAT48 Demo Boards Cascaded Together to Drive More Than 6 LED Channels. 4 Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

5 EV9 Evaluation Board for the AAT48 Functional Test and Evaluation R SET and DOT Register The R SET resistors, R, on the AAT48 is 6.04kΩ, and set the maximum full scale LED current to 0.7mA. The DOT correction register provides 56 linear steps between current sink being off and the maximum full scale LED current to adjust the luminance of the LEDs. Figure 4 shows the LED current at its full scale setting with DOT register sets to 0xFF. Figure 5 shows the LED current at its half scale setting with DOT register sets to 0x80. Figure 5: LED Current with DOT = 0xFF. Figure 6: LED current with DOT = 0x80. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0 5

6 EV9 Evaluation Board for the AAT48 GS Registers The GS registers control the PWM duty cycle of the LED current sinks for adjusting the brightness. Figure 6 shows a LED string running at 50% duty with GS register sets to 0x800. Figure 7 shows a LED string running at 5% duty with GS register sets to 0x400. Figure 8 shows a LED string running at 75% duty with GS register sets to 0xC00. Figure 7: PWM at 50% Duty Cycle with GS = 0x800. Figure 8: PWM at 5% Duty Cycle with GS = 0x Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

7 EV9 Evaluation Board for the AAT48 Figure 9: PWM at 75% Duty Cycle with GS=0xC00. DLY Registers The DLY registers set the phase shift from the rising edge of VSYNC to when the current sink PWM cycle begins for each LED current sink. Figure 9 shows a phase shift of 0 with DLY register setting to 0x000. Figure 0 shows a phase shift of 90 with DLY register sets to 0x400. Figure shows a phase shift of 80 with DLY register setting to 0x800. Figure shows a phase shift of 70 with DLY register setting to 0xC00. Figure shows a phase shift of 60 with DLY register setting to 0xFFF. One advantage of using delay is that it allows each current sink to start at different time to reduce the stress on a system power supply. The other advantage is that it can provide a fixed off time in scanning mode when the delay is used in combination with the INVERT function. Figure 0: 0 Phase Shift with DLY = 0x000. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0 7

EV9 Evaluation Board for the AAT48 Figure : 90 Phase Shift with DLY = 0x400. Figure : 80 Phase Shift with DLY = 0x800. 8 Skyworks Solutions, Inc.

8 EV9 Evaluation Board for the AAT48 Figure : 90 Phase Shift with DLY = 0x400. Figure : 80 Phase Shift with DLY = 0x Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

9 EV9 Evaluation Board for the AAT48 Figure : 70 Phase Shift with DLY = 0xC00. Figure 4: 60 Phase Shift with DLY = 0xFFF. INVERT Function The INVERT function allows the PWM signal to be inverted. A 5% duty cycle (GS = 0x400) with the INVERT function enabled will be a 75% duty cycle output. A 90 delay turn-on time (DLY = 0x400) with the INVERT function enabled will have a turn-on time at 90. The INVERT function can provide a fixed off time in scanning mode. Figure 4 and 5 show two PWM waveforms with INVERT function disabled, sharing the same turn-on time with different duty cycle. Figure 6 and 7 show two PWM waveforms with the same setting as Figure 6 and 7 with INVERT function enabled. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0 9

10 EV9 Evaluation Board for the AAT48 Figure 5: Non-Inverted 0% Duty Cycle with 45 Phase Shift Turn-On Time (GS = 0x, DLY = 0x00, INVERT = 0). Figure 6: Non-Inverted 80% Duty Cycle with 45 Phase Shift Turn-On Time (GS = 0xCCC, DLY = 0x00, INVERT = 0). 0 Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

11 EV9 Evaluation Board for the AAT48 Figure 7: Inverted 0% Duty Cycle with 45 Phase Shift Turn-Off Time (GS = 0x, DLY = 0x00, INVERT = ). Figure 8: Inverted 80% Duty Cycle with 45 Phase Shift Turn-Off Time (GS = 0xCCC, DLY = 0x00, INVERT = ). Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

EV9 Evaluation Board for the AAT48 Open and Short Fault Detection The AAT48 provides the open and short fault detection to detect any LED that is open or short.

12 EV9 Evaluation Board for the AAT48 Open and Short Fault Detection The AAT48 provides the open and short fault detection to detect any LED that is open or short. The fault status is indicated by the FLT pin and Fault Status registers. The AAT48 has a programmable open fault blanking time. The blanking time can be programmed to, 4, 8, or 6 VSYNC cycles to prevent any false fault detection due to the slow system response from SMPS at PWM startup. The AAT48 does not provide short fault blanking time. The AAT48 has an open fault clear bit and a short fault clear bit. By setting the fault clear bit, the fault status is removed and any further fault will not be detected until the bit is reset back to 0. Figure 8, 9, 0 and show the, 4, 8, and 6 VSYNC blanking time settings in open fault detection. Figure shows the short fault detection without any VSYNC blanking time. Figure 9: Open Fault with the VSYNC Blanking Time. Figure 0: Open Fault with the 4 VSYNC Blanking Time. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

Phone [78] 76-000 Fax [78] 76-00 sales@skyworksinc.

13 EV9 Evaluation Board for the AAT48 Figure : Open Fault with the 8 VSYNC Blanking Time. Figure : Open Fault with the 6 VSYNC Blanking Time. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

14 EV9 Evaluation Board for the AAT48 Figure : Short Fault Detection No VSYNC Blanking. 4 Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

15 EV9 Evaluation Board for the AAT48 Layout Guidelines Follow the guidelines below to ensure proper operation of the AAT48:. Maintain a ground plane and connect to the IC pin(s), and minimize the distance from the input capacitor negative terminal to the pins.. Consider additional PCB exposed area for the AAT48 to maximize heat sinking capability. Connect the EP (bottom of the die) to. Connect and S as close as possible to the package and maximize the heat sinking space for overall performance.. Maximize package thermal dissipation and power handling capacity of the QFN77-48 package, solder the exposed paddle of the IC onto the thermal landing of the PCB, where the thermal landing is connected to the ground plane. If heat is still an issue, multi-layer boards with dedicated ground planes are recommended. Also, adding thermal vias with 0.mm hole size and.mm spacing between the vias (Refer to Figures and ) on the thermal landing would help transfer heat to the bottom plane of the PCB effectively. Component Part Number Description Manufacturer U AAT48 6 Channels White LED Driver Skyworks C5 UMK6BJ475KL-T Cap Cer 4.7μF 50V X5R 06 Taiyo Yuden C, C, C GRM88R6C5KE5D Cap Cer.μF 6V X5R 060 Murata D LL448- Diode Switch 75V 500MW MINIMELF Diode Inc. R CRCW0606K04FKEA Res 6.04KΩ /0W % 060 SMD R CRCW0600K0FKEA Res 0KΩ /0W % 060 SMD R CRCW060KFKEA Res.KΩ /0W % 060 SMD Vishay R5, R6, R7, R8, R9, R0 CRCW Z0EA Res 0Ω /0W % 060 SMD JP, JP, JP, JP4 TSW-0-08-G-D Conn. Header Pos,.54mm JP5, JP6 TSW-0-08-G-D Conn. Header 4 Pos,.54mm Samtec, Inc. P HRP0H-ND Header 5x-Pin, Dual Row,.54mm P AWHW0G-00-T-R Header 0x-Pin, Dual Row,.54mm Assmann P, P5, P7, P9, P Right Angle Conn Socket,.54mm P4, P6, P8, P0, P Right Angle Header,.54mm Mill-Max Table : AAT48 Evaluation Board BOM. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0 5

6 Skyworks Solutions, Inc. Phone [78] 76-000 Fax [78] 76-00 sales@skyworksinc.

16 EV9 Evaluation Board for the AAT48 Figure 4: AAT48IDX (7mm 7mm TDFN) Evaluation Board Layout Top Layer. Figure 5: AAT48IDX (7mm 7mm TDFN) Evaluation Board Layout Bottom Layer. 6 Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0

17 EV9 Evaluation Board for the AAT48 Copyright 0 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, IN- CLUDING 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 are incorporated by reference. Skyworks Solutions, Inc. Phone [78] Fax [78] sales@skyworksinc.com 08A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. September, 0 7

Figure 1: AAT2469/AAT2499 Evaluation Board Picture.

Figure 1: AAT2469/AAT2499 Evaluation Board Picture. Introduction EVALUATION BOARD DATA SHEET The AAT246/AAT24 evaluation board is a hardware platform to evaluate the functions of the AAT246 and AAT24 devices. The AAT246 is a dedicated TVLite TM control