EV183 EVALUATION BOARD DATA SHEET. Evaluation Board for the AAT2822/2823/2824/2825 TFT-LCD DC-DC Converter with WLED Driver and VCOM Buffer

Transcription

1 EVALUATION BOARD DATA SHEET EV Evaluation Board for the AAT/// Introduction The AATx family (AAT, AAT, AAT, AAT) of integrated panel power solutions provides the regulated voltages required by an active-matrix thin-film transistor (TFT) liquid-crystal display (LCD). The AATx family includes a boost DC-DC converter for LCD bias up to.v, two charge pumps up to ±0V, a WLED backlight driver up to V, and a VCOM buffer in a mm x mm TQFN package. The AATx have power sequence of VA -> VGH -> VGL. The AATx- have power sequence of VA -> VGL -> VGH. This document highlights the use of the AATx family evaluation board to demonstrate the functions and performance of the AATx power ICs. A brief Getting Started section is included to help the user to set up and operate the evaluation board. The board is shown in Figure. Figure and Figure depict the board schematic and layout. For additional information, refer to the AATx product datasheets. Board Pictures (a) Top (b) Bottom Figure : AATxIBK Evaluation Board. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

2 Board Schematic EVALUATION BOARD DATA SHEET EV Evaluation Board for the AAT/// OP- WLED- WLED+ VGL (negative) R 0kΩ W J J J OVP 0.V R adj C.μF J stage stage stage 0.μF.V C 0.μF V C9 0.μF C0 0.μF C 0.μF D C7 C 0μF V.V L.μH R0.0kΩ R9 -WLED A BATSDW A 0V BATSDW PWM R0 J W C 0.μF V C 0.μF C 0.μF C 0.μF C 0.μF V W 0V C.7μF WDIM PGND REF W 7 0.μF V 0.μF C R 0V C 0.μF 9 OVP 0 0 WFB AAT OVP PGND R 9 WCOMP J A C0 BATSDW A C7 0.μF adj 7.kΩ R U R OUT OP+ OPIN FB COMP C9.nF 7 0.V R R7.0kΩ C 0.μF V C7 0.μF 0 R7 R 0kΩ R 00kΩ C 0pF V J J9 C 0nF R R R 0kΩ stage stage C 00pF L.μH C 0.μF D R R9 C 0μF 0V C μf V WFB 0.V R R.0kΩ VA R A R C J7 HF-PWM VA VOPIN C 0.μF C9 0.μF J0 stage VGH (positive) BATSDW C0 0.μF Figure : AATIBK Evaluation Board Schematic. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

3 EV Evaluation Board for the AAT/// WLED- WLED+ VGL (negative) R 0kΩ W J J J OVP 0.V R adj C.μF J stage stage stage 0.μF.V C 0.μF V C9 0.μF C0 0.μF C 0.μF D C7 C 0μF V.V L.μH R0.0kΩ R9 -WLED A BATSDW A 0V BATSDW PWM R0 J W C 0.μF V C 0.μF C 0.μF C 0.μF C 0.μF V W 0V C.7μF WDIM PGND REF W 7 0.μF V 0.μF C R 0V C 0.μF 9 OVP 0 0 WFB AAT OVP PGND R 9 WCOMP J A C0 BATSDW A C7 0.μF adj 7.kΩ R U R FB COMP 7 0.V R C9 nf R7.0kΩ C 0.μF V C7 0.μF R 00kΩ C 0pF V J J9 stage stage C 00pF L.μH D R R9 C 0μF 0V C μf V WFB 0.V R R.0kΩ VA R A R C HF-PWM VA C 0.μF C9 0.μF J0 stage VGH (positive) BATSDW C0 0.μF Figure : AATIBK Evaluation Board Schematic. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

4 EV Evaluation Board for the AAT/// 0V C.7μF R 0V C 0.μF 0 R7 C 0nF VGL (negative) 0.μF.V C7.V R0.0kΩ R9 0V PGND REF W 0 AAT PGND 9 U OUT OP- OP+ OPIN FB COMP 7 R 0kΩ R 00kΩ R R R 0kΩ C 00pF L.μH C 0.μF C 0μF 0V 0.V R R.0kΩ J7 VOPIN D VA W J J J J stage stage stage C 0.μF V C9 0.μF C0 0.μF C 0.μF A BATSDW A BATSDW C 0.μF V C 0.μF C 0.μF C 0.μF C 0.μF V C0 0.μF V C 0.μF C7 0.μF J A BATSDW A 0.V R R7.0kΩ C 0.μF V C7 0.μF C 0pF V J J9 stage stage R R9 C μf V VA A C 0.μF C9 0.μF J0 stage VGH (positive) BATSDW C0 0.μF Figure : AATIBK Evaluation Board Schematic. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

5 EV Evaluation Board for the AAT/// 0V C.7μF R 0V C 0.μF 0 9 U VGL (negative) 0.μF.V C7.V R0.0kΩ R9 0V PGND REF W AAT PGND FB COMP 7 R 00kΩ C 00pF L.μH C 0μF 0V 0.V R R.0kΩ D VA W J J J J stage stage stage C 0.μF V C9 0.μF C0 0.μF C 0.μF A BATSDW A BATSDW C 0.μF V C 0.μF C 0.μF C 0.μF C 0.μF V C0 0.μF V C 0.μF C7 0.μF J A BATSDW A 0.V R R7.0kΩ C 0.μF V C7 0.μF C 0pF V J J9 stage stage R R9 C μf V VA A C 0.μF C9 0.μF J0 stage VGH (positive) BATSDW C0 0.μF Figure : AATIBK Evaluation Board Schematic. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

6 EV Evaluation Board for the AAT/// Getting Started Setup. Connect an input power source (to supply between.v and.v) between and ground.. Connect the jumpers to the positions shown in Figure.. Place the J jumper to the ON position before connecting the external WLED. To reduce inrush current, do not enable the main boost and the white LED driver concurrently. (a) Jumper Position when WLED Disabled b) Jumper Position when WLED Enabled Table shows the jumper functions. Figure : AATx Evaluation Board Measurement Configuration. Jumper J J J J, J, J J, J9, J0 J7 Description Enable the V A, V GH, and V GL channels by setting the jumper from OFF to ON position. Enable the WLED by setting the jumper W from OFF to ON position. LED dimming control input to WDIM. Set to 00 position for maximum brightness and 0 position for shut down. Apply an external PWM signal up to khz to pin of J by removing the jumper and adjust the duty cycle of the PWM signal from 00% to %, the LED brightness will change proportionally. Stage select for V GL channel with one of the three jumpers: J for two stages selection; J for three and J for four. Detail stage selection is discussed in section: Boost and Dual Charge Pump Output Setting. Stage select for V GH channel with one of the three jumpers: J for two stages selection; J for three and J for four. Detail stage selection is discussed in section: Boost and Dual Charge Pump Output Setting. Connect J7 OPIN for using V A as VCOM buffer input voltage (V OPIN ). The maximum input bias voltage for the VCOM buffer cannot exceed V. To prevent damage to the device when V A is greater than V, OPIN should be connected to an external supply to the top pin of J7 by removing the jumper. Table : AATx Evaluation Board Jumper Functionality. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

7 Functional Testing and Evaluation EVALUATION BOARD DATA SHEET EV Evaluation Board for the AAT/// Measurement for Boost and Dual Charge Pumps The boost of LCD bias and dual charge pumps can be measured by test points of VA, VGH and VGL. The boost output voltage can be set up to.v and the outputs, VGH and VGL, of the two charge pumps can be set up to +0V and -0V by external resistor dividers. For details refer to the section: Boost and Dual Charge Pumps Output Setting. Figure 7 shows the configuration and the waveforms for the power up sequencing of the AATx- boost and the dual charge pumps. A Hz pulse signal is fed in to the Enable pin,. V IN is V, V A is 0V, V GH is V, V GL is 0V. The waveform shows the power sequence is V A -> V GL -> V GH. (a) Measurement Configuration (b) Waveform of AAT- Power-up Sequence Figure 7: AAT Evaluation Board Boost and Dual Charge Pump Measurement. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0 7

8 Measurement for WLED Backlight Driver EVALUATION BOARD DATA SHEET EV Evaluation Board for the AAT/// The WLED backlight driver is a step-up DC-DC converter with sense resistor to provide feedback voltage. Its input voltage, V DD, on the board is either V A with R9 set to or external V IN with R set to. The WLED brightness can be adjusted by either the PWM dimming or the ballast resistor (R). The PWM signal can be fed in through WDIM pin at pin of jumper J. The ballast resistor is used to set the maximum WLED current. For details refer to the section: WLED Backlight. Figure shows the configuration and the measurement waveforms with R = Ω at V V IN. The current for each string is 0mA. In this configuration, series parallels WLEDs (SP), the total current is 00mA. (a) Measurement Configuration (b) Waveform for WLED SP Configuration Figure : AAT Evaluation Board Backlight Driver Measurement Operation. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

9 Measurement for LCD VCOM Buffer EVALUATION BOARD DATA SHEET EV Evaluation Board for the AAT/// The VCOM buffer is designed to drive the voltage on the backplane of an LCD display. The VCOM output voltage is typically set to half of the main boost output (V A ). Figure 9 shows the configuration for the measurement. The maximum input bias voltage for the VCOM buffer (V OPIN ) cannot exceed V. To prevent damage to the device, connect V OPIN to an external supply when V A is greater than V and leave the jumper J7 to disconnect V A from V OPIN. Figure 9: AATx Evaluation Board: Measurement Configuration for VCOM Buffer Output. Boost and Dual Charge Pump Output Setting The output voltage V A of the LCD bias boost is set by external resistor divider R and R. The dual charge pumps output voltages are determined by both resistor divider and charge pump stages. Table shows the resistor divider selection equation and table shows the charge pump stage selection equation. Output Channel Output Range Equation For ustable Resistor V A V FB V A V IN - V DIODE to.v R = R - = R - Eq. 0.V V A V GL to 0V R9 = R0 =.V R0 Eq. V GL V REF V GL V GH - to -0V R = R7 - = R7 - Eq. 0.V V GH V V GH Table : Resistor Divider Equations for Boost and Dual Charge Pumps. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0 9

10 EV Evaluation Board for the AAT/// Charge Pump V GL Equation For Stage Selection V GL n N = V F - V A(MIN) Eq. V GH n P = V GH - V A(MIN) V A(MIN) - V F Eq. Table : Charge Pump Stage Selection Equations. For example, if V A = V, V GH = V and the forward voltage of the Schottky diode V F is 0.V. - n P = = So, to set V GH to V, three stages need to be used (J must be connected and J, J left ). WLED Backlight WLED brightness can be adjusted either by setting the ballast resistor for max WLED current or by varying the duty cycle of the PWM signal. Ballast Resistor Selection The white LED driver can be enabled by setting J from OFF to ON position. The backlight current is set by an external ballast resistor (R) up to a maximum of 0mA at V or 0mA at V. The AATx can drive from WLEDs up to a maximum of 7 WLEDs in series. The number of WLEDs depends on the LCD panel size. Table gives some examples of different LCD panel size and corresponding WLED configurations. The brightness of the white LED can be controlled by a PWM signal. By connecting a khz PWM signal to the WDIM pin and adjusting the duty cycle of the PWM signal from 00% to %, the brightness of the LED will change proportionally. The higher frequencies are achieved by filtered PWM and the value of R, R, R, C should be calculated. See AAT datasheet for more details. The equation for calculating OVP adjustable resistor (R) is: where V LED(MAX) V OVP V LED(MAX) R = R - = R 0.V - V LED(MAX) equals the forward voltage of the WLED series plus 0.V V WFB. The equation for the number of series-connected LEDs is given by: N = V OVP(MIN) - V WFB(MAX) V FLED(MAX) = V OVP(MIN) - 0.V.V So, for example, when V OVP(MIN) = V, V WFB(MAX) = 0.V, and V FLED(MAX) =.V N = V - 0.V.V = 7. LEDs The maximum number of WLEDs in series for the given V OVP output range is, therefore, seven. 0 Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

11 The equation for calculating ballast resistor (R) is: EVALUATION BOARD DATA SHEET EV Evaluation Board for the AAT/// R = V 0.V WFB(MAX) = I LED(MAX) I LED(MAX) For example, for a 0-inch panel with series and parallel (SP) string configuration and the maximum current in each string being 0mA: 0.V R = =.Ω 0mA WLED Matrix (Series and Parallel) SP Maximum I LED Current (ma) Ballast Resistor R (Ω) WLED Matrix (Series and Parallel) Maximum I LED Current (ma) Ballast Resistor R (Ω) SP Table : Ballast Resistor Selection. Maximum WLED Output Current Maximum WLED output current is determined by both WLED driver input voltage V IN_WLED and WLED string voltage V LED. Figure 0 shows the relationship of the three factors. 00 I LED_MAX (ma) V IN_WLED =.V V IN_WLED =.V V IN_WLED = V V IN_WLED = V V IN_WLED = 0V V IN_WLED = V V IN_WLED = V V IN_WLED = V V IN_WLED = 0V 0 0 V LED (V) Figure 0: WLED Driver Maximum Output Current for different V LED Voltage. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

12 EV Evaluation Board for the AAT/// PWM Dimming The brightness of the white LED can be controlled using a PWM signal. By connecting a khz PWM signal to pin of jumper J and adjusting the duty cycle of the PWM signal from % to 00%, the brightness of the LED will change proportionally. Figure shows the variation of ILED with the PWM duty cycle. 0 I LED (ma) PWM Duty Cycle (%) Figure : khz PWM control (V IN = V, I LED(MAX) is set to 0mA). For applications requiring a PWM frequency higher than khz, an external filter PWM is connected to the WFB pin to control the dimming of the white LED. Connect the PWM signal from "HF-PWM" test point and connect WDIM Pin to. Figure shows a low path filter used in the high frequency PWM control application. In this method, the LED dimming has relationship with both PWM high voltage level and duty cycle. WLED- VR adj R Connect WDIM to I VWFB I R.99k 0 9 U I R k VC R.99k C 0.uF HF-PWM W WDIM OVP WFB WCOMP PGND OUT PGND OP- REF OP+ AAT OPIN W FB COMP Figure : Low-Pass Filter PWM Dimming Control. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

13 EV Evaluation Board for the AAT/// When the PWM duty cycle is adjusted, the average voltage on C(V C ) will change. Because the V WFB is fixed at 0.V, so I and I will change. The changed I will adjust the voltage drop, V DROP, across R. The voltage across resistor R, V R, changes, leading to the change of the white LED current. Figure shows PWM control by changing the PWM duty cycle with.v high level and 0V low level. Figure shows PWM control by varying the PWM high level with 0% fixed duty cycle. The following example illustrates the calculations for I LED in a SP matrix where the PWM high level voltage is.v, the frequency is 0kHz the duty cycle is 0%, and R = Ω. I = I + I = kω = 0.0mA V R = V WFB I R = mA.99kΩ = 0.0V V R ILED = = 0.0 = ma (Total current in parallel strings) R Note: If the voltage in C is lower than V WFB, the current direction will reverse and I will equal I - I. This will cause V R to be pulled up and decrease I LED. 0 I LED ma) HF_PWM Duty Cycle (%) Figure : 0kHz High Frequency PWM Control by PWM Duty Cycle (V IN = V, I LED(MAX) = 0mA). Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

14 EV Evaluation Board for the AAT/// 0 I LED (ma) High level of PWM Signal (V) Figure : 0kHz High Frequency PWM Control by PWM High Level Voltage (V IN = V, I LED(MAX) = 0mA). Printed Circuit Board (a) Top Layer (b) Bottom Layer Figure : AATxIBK Evaluation Board. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

15 EV Evaluation Board for the AAT/// Layout Guidelines Use the following guidelines to ensure proper operation of the AATx:. Minimize the distance from the input capacitor negative terminal to the GND pins.. Maintain a ground plane and connect to the IC GND pin(s) as well as the GND connections of CIN and COUT.. Connect PGND and as close as possible to the package and maximize the heat sinking space for overall performance.. To maximize package thermal dissipation and power handling capacity of the TQFN- 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. AATx EVAL Board Component Listing Component Part Number Description Manufacturer U AAT///IBK TFT-LCD DC-DC Converter with WLED Driver and VCOM Buffer Skyworks C GRMRA7K CAP CERAMIC.7μF 00 XR 0V 0% C GRMR7C0K CAP CERAMIC 0.μF 00 X7R V 0% C, C GRMBRC0K CAP CERAMIC 0μF 00 XR V 0% C GRMCR7HK CAP CERAMIC.μF 0 X7R 0% C GRMCREM CAP CERAMIC μf 0 XR V 0% C7 GRMR7AK CAP CERAMIC 0.μF 00 X7R 0V0% C GRMCH0J CAP CERAMIC 00pF 00 COG % C9 GRM9CHJ CAP CERAMIC.nF 00 X7R 0% C0, C, C, C GRMRE0K CAP CERAMIC 0.μF 00 XR V 0% Murata C, C, C, C, C7, C GRMR7H0K CAP CERAMIC 0.μF 00 X7R 0% C, C GRMREK CAP CERAMIC 0.μF 00 XR V0% C7, C9, C0, C, C9, C0 GRMBR7HK CAP CERAMIC 0.μF 00 X7R 0% C GRMR7H0K CAP CERAMIC 0nF 00 X7R 0% C NC C GRMCH00J CAP CERAMIC 0pF 00 COG % A, A, A, A BATSDW-7-F Schottky Diode Array 0V SC70- Diode Inc D, D SSL Schottky Diode A 0V Micro SMP Taiwan Semiconductor L, L CDRHD-R POWER INDUCTOR.μH.0A SMD Sumida R, R, R, R, R9 ustable Value (See Equations and Table ); 00 SMD R, R7, R0 RC00FR-07K0L Res.0kΩ /0W % 00 SMD R, R, R RC00FR-070KL Res 0kΩ /0W % 00 SMD R RC00FR-0700KL Res 00kΩ /0W % 00 SMD R RC00FR-077KL Res 7.kΩ /0W % 00 SMD Yageo R, R9, R0, R RC00FR-070RL Res /0W % 00 SMD R7 RC00FR-0700RL Res 0 /0W % 00 SMD R, R, R, R, R Not Populated Table : AAT Evaluation Board Bill of Materials. Skyworks Solutions, Inc. Phone [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0

16 EV Evaluation Board for the AAT/// 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-INFRINGEMT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES NOT WARRANT THE ACCURACY OR COMPLETESS 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, INCIDTAL, STATUTORY, OR CONSEQUTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVUES OR LOST PROFITS THAT MAY RESULT FROM THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIT OF MATERIALS HAS BE 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 [7] Fax [7] 7-00 sales@skyworksinc.com 09A Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. August 0, 0