Introduction The AAT09/07/0 evaluation board provides a platform for evaluating the family of 8-channel / 6-channel / -channel LED backlight drivers. The PCB layout has been optimized for portable device applications with a minimum number of external components in a small area. The design operates across an input voltage range of.v to.v (if V IN = V CC ) or.0v to 6V (if V IN is connected only with V CC open). Schematics V IN V - 6V D V OUT 0 LEDs in series L.7μH MSSP6 C 0µF V JP C 0V JP JP C nf JP R.99k R 7.k 6 EN IN VCC PWM COMP RSET FSET SYNC 9 S LX AAT09 P 8 0 OVP 7 CS 6 CS 7 CS 8 CS 9 CS CS6 CS7 CS8 0 EP R k R.k U TQFN- C 080 L Sumida, CDRHD8RHPNP-R7N,.7μH,.7A, DCR =.mω D Vishay, Schottky Barrier Diode, MSSP6, A, 60V C Taiyo Yuden, GMKBJ06KN-T, 0μF, V, XR,0; OR Murata GRMER7H06K, 0μF,, X7R, 0 C.μF, 0V, 060 C Cap, nf, 0V, 060 C Murata, GRMCR7HKA88L,.μF,, X7R, 06 R, R, R, R Carbon Film resistors, %, 060 Figure : AAT09 Evaluation Board Schematic.
V IN V - 6V D V OUT 0 LEDs in series L.7μH MSSP6 C 0µF V JP C 0V JP JP C nf JP R.99k R 7.k 6 U TQFN- EN IN VCC PWM COMP RSET FSET SYNC 9 S LX AAT07 P OVP 7 CS 6 CS 7 CS 8 CS 9 CS CS6 EP R k R.k C 080 0 8 0 L Sumida, CDRHD8RHPNP-R7N,.7μH,.7A, DCR =.mω D Vishay, Schottky Barrier Diode, MSSP6, A, 60V C Taiyo Yuden, GMKBJ06KN-T, 0μF, V, XR,0; OR Murata GRMER7H06K, 0μF,, X7R, 0 C.μF, 0V, 060 C Cap, nf, 0V, 060 C Murata, GRMCR7HKA88L,.μF,, X7R, 06 R, R, R, R Carbon Film resistors, %, 060 Figure : AAT07 Evaluation Board Schematic.
V IN V - 6V D V OUT LEDs in series L.7μH MSSP6 C 0µF V JP C 0V JP JP C nf JP R.99k R 7.k 6 EN IN VCC PWM COMP RSET FSET SYNC 9 S LX AAT0 P 8 0 OVP 7 CS CS CS CS 0 EP 6 7 8 9 R k R.k U TQFN- C 080 L Sumida, CDRHD8RHPNP-R7N,.7μH,.7A, DCR =.mω D Vishay, Schottky Barrier Diode, MSSP6, A, 60V C Taiyo Yuden, GMKBJ06KN-T, 0μF, V, XR,0; OR Murata GRMER7H06K, 0μF,, X7R, 0 C.μF, 0V, 060 C nf, 0V, 060 C Murata, GRMCR7HKA88L,.μF,, X7R, 06 R, R, R, R Carbon Film resistors, %, 060 Figure : AAT0 Evaluation Board Schematic.
Test Equipment. Unit under test (UUT) is the AAT09/07/0 Evaluation Board.. One () XT0- Power Supplies or equivalent.. One PWM Function Generator.. One Fluke 89 multi-meter or equivalent to measure the output voltage.. Miscellaneous test leads (banana plug to clip lead type is recommended). Setup and Test Quick Setup Guide. Configure and verify the evaluation board as shown in Figure prior to applying any power.. Verify the jumper JP at ON position; disable the synchronization function using jumper JP; set the switching frequency either at 67kHz (Lo) or.mhz (Hi) using JP.. Connect a function generator to JP with the PWM amplitude from 0V to V, the PWM frequency range from 00Hz to 00 khz, and the PWM duty cycle range from % to 99%.. Connect a V power supply to the input voltage (VIN), and connect an appropriate WLED board to the to LED Panel terminal on the board.. Turn on the Power Supply; the LED panel should be turn ON. 6. Vary the PWM frequency while monitoring the LED dimming, and vary the dimming of the LED panel by adjusting the PWM duty cycle.
Setting Over-Voltage Protection (OVP) The resistor divider must be selected so that the voltage at the OVP pin exceeds the OVP rising threshold at V OUT(MAX) and the maximum LX voltage does not exceed its maximum value (). Therefore, the value of R should be chosen within the range of the following equation: Where: V CSX + N V FLED(MAX) - V OVP(MIN) R < R < R - V OVP(MIN) V OVP(MAX) R =.kω is selected for minimizing losses without degrading noise immunity. N is the number of LEDs in each string. V OVP(MIN) =.V is minimum over-voltage threshold. V OVP(MAX) =.V is maximum over-voltage threshold. V CSX = 0.V is the current sink voltage. V FLED(MAX) is the maximum forward LED voltage at 0mA. For example, if the number of the white LED in each string is N =, the resistor divider R can be calculated by selecting R =.kω: 0.V +.7V -..kω < R <.kω -..V.kΩ < R <.kω; choose R = kω (closest % value) Check the maximum output voltage with the selected values of R, R: R kω V OUT(MAX) = V OVP(MAX) + =.V + = 8.8V < R.kΩ
LED Current Sink Setting The current sink is set by the R resistor: Where V RSET = 0.6V R = 6 V RSET 6 0.6V = I CSX(MAX) I CSX(MAX) For example, if the maximum current for each string LEDs is 0mA, this corresponds to a minimum resistor of.kω. R = 6 0.6V 0mA =.kω Maximum I LED Current (ma) R (kω).8 0. 6.9 0 7.87 0. 0.8.6 Table. Maximum LED Current Sink vs. R SET Resistor (R ) Values.. AAT09 only. 6
Figure : AAT09 Evaluation Board Quick Setup Guide Connection Diagram.. Applied the same for both AAT07 and AAT0 evaluation boards. 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 www.skyworksinc.com, are incorporated by reference. 7