Data Sheets - Skyworks Solutions, Inc.

EVALUATION BOARD DATA SHEET
EV174
Evaluation Board for the AAT1401
Serial LED Driver with Filtered PWM and 32-Step S2C Dimming Control
Introduction
The AAT1401 evaluation board demonstrates the functionality of the WLCSP-10 packaged AAT1401 and its application
as a white LED driver under Skyworks' S2Cwire serial digital interface control or filtered PWM interface control.
The AAT1401 is a step-up single current sink LED driver with an input voltage range of 2.7V to 5.5V. The wide input
voltage range, small solution size, advanced dimming features and high efficiency is suitable for LED backlight solutions
for single cell Li-ion based equipment. A precision, high voltage current sink maintains the maximum LED current set
by an external resistor from 10 to 31mA. The high switching frequency supports ultra small, low cost filtering components. This document describes the evaluation board and its accompanying user interface. A brief “Getting Started”
section is included to help the user to begin operating the evaluation board. The AAT1401 evaluation board is shown
in Figure 1; Figures 2 and 9 depict the board schematic and layout. For additional information, please consult the
AAT1401 product datasheet.
Board Picture
a: Top Side
b: Bottom Side
Figure 1: AAT1401IUQ Evaluation Board Picture.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202315A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 29, 2012
1
EVALUATION BOARD DATA SHEET
EV174
Evaluation Board for the AAT1401
Serial LED Driver with Filtered PWM and 32-Step S2C Dimming Control
Schematic
DS1
SDM20U40
L1 10µH
R1
1M
U1
AAT1401IUQ
J1
VIN
DC+
CIN
4.7µF
DC-
A2
A1
LX
PWM
D1
R2
51k
D3
OVP
D2
A3
EN/SET
B3 PWM
VIN
R3
51k
AAT1401
White LED
Driver
IN
J2
D3
C3
COMP
D2
RSET
CCOM
56nF
D4
C1
GND
B1 PGND
RSET
15k
D1
CS
D6
D5
R4
51k
V_MCU
S2Cwire/PWM
Microcontroller
PWM
EN/SET
S2C
R7 R8 R9
1k 1k 1k
U2
1
2
3
4
UP
PIC12F675
VDD
GP5
GP4
GP3
VSS
GP0
GP1
GP2
C1
0.1µF
8
7
R6 51k
6
5
R5
1k
LED1
Red
VMCU
DOWN
3
2
1
J3
CYCLE
Figure 2: AAT1401IUQ Evaluation Board Schematic.
2
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202315A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 29, 2012
COUT
0.1μF/50V
EVALUATION BOARD DATA SHEET
EV174
Evaluation Board for the AAT1401
Serial LED Driver with Filtered PWM and 32-Step S2C Dimming Control
Getting Started
The board has two terminals labeled DC+ and DC- for the input power supply connection. Set the jumper J1 to the left
position to connect the DC+ power to AAT1401 IN. Jump V_MCU to connect the DC+ power to microcontroller VIN.
Jump PWM and EN/SET to connect the microcontroller GPIOs to the AAT1401 PWM and EN/SET pins. Jump J3 to the
S2C position to set the microcontroller to generate S2Cwire code signal to set the maximum LED current of the AAT1401
by 32 steps of S2C code up to 20mA with 15kΩ RSET. After all jumpers are in the correct positions, apply power between
2.7V and 5.5V to the DC+ and DC- terminals to power the AAT1401 (U1) and microcontroller (U2); the red LED (LED1)
should illuminate when the microcontroller is powered. After setting the maximum LED current by pressing the buttons,
jump J3 to the PWM position to set the microcontroller to generate PWM signal with varied duty cycle between 5% and
100% in 5% steps to dim the LED current. Figure 3 shows the connection of the AAT1401 board under microcontroller
S2Cwire control or both S2Cwire and PWM control.
a. Operation Using S2Cwire Control Only
b. Operation Using Filtered PWM Control When Finish Max Current Setting. Figure 3: AAT1401 Evaluation Board Demonstration Connection
The 6 white LEDs may be dimmed or brightened using the EN/SET serial data S2Cwire interface or both S2Cwire and
PWM interface through the three buttons: UP, DOWN and CYCLE.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202315A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 29, 2012
3
EVALUATION BOARD DATA SHEET
EV174
Evaluation Board for the AAT1401
Serial LED Driver with Filtered PWM and 32-Step S2C Dimming Control
S2Cwire Control Only
Set J3 to the S2C position to set the microcontroller to generate S2Cwire data according to the status of the three buttons. The AAT1401 records rising edges of the EN/SET pin and decodes them into 32 maximum individual current level
settings from 20mA to 0.4mA with RSET = 15kΩ.
• UP button: The UP button increments the number of EN/SET edges from 1 to 32 when the button is pushed once.
When the button is held down for more than 0.6 seconds, the microcontroller enters auto-increment mode. The LED
will dim and wrap back after S2Cwire data 32.
• DOWN button: The DOWN button decrements the number of EN/SET edges from 32 to 1 when the button is pushed
once. When the button is held down for more than 0.6 seconds, the microcontroller enters auto-decrement mode.
The LED will brighten and wrap back after S2Cwire data 1.
• CYCLE button: The button increment or decrements the number of EN edges automatically and cyclically after a
single push according to the previous EN edges up or down event.
• UP+DOWN+CYCLE button: EN is set to 0V after the three buttons are pressed at the same time and the AAT1401 is
shut down. All white LEDs are turned off.
22
20
18
ILED (mA)
16
14
12
10
8
6
4
2
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
S2C Code
Figure 4: S2Cwire Dimming Control at Maximum LED Current (20mA max).
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202315A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 29, 2012
EVALUATION BOARD DATA SHEET
EV174
Evaluation Board for the AAT1401
Serial LED Driver with Filtered PWM and 32-Step S2C Dimming Control
PWM Dimming with Maximum Current Set by S2Cwire
When using both S2Cwire and PWM control, the maximum LED current is set by the EN/SET S2Cwire interface and LED
brightness is changed via PWM by varying the duty cycle from the set maximum LED current to almost zero value.
PWM control sets the microcontroller to generate a square waveform with duty cycle from 5% to 100% in 5% steps to
adjust the LED current according to the status of the three buttons.
The operation steps are:
1.
2.
3.
4.
Set J3 to the S2C position.
Power on and use the UP or DOWN button to set the white LED current value to the desired maximum LED current.
Set J3 to the PWM position.
Press one of the three buttons to observe the white LED dimming or brightening under PWM control with varied
duty cycle.
• UP button: The UP button increments the duty cycle from 5% to 100% with 5% steps when the button is pushed
once. When the button is held down for more than 0.6 seconds, the microcontroller enters auto-increment mode.
The LED will brighten to 100% and wrap back to 5%.
• DOWN button: The DOWN button decrements the duty cycle from 100% to 5% with 5% steps when the button is
pushed once. When the button is held down for more than 0.6 seconds, the microcontroller enters auto-decrement
mode. The LED will dim to 5% and wrap back to 100%.
• CYCLE button: The button increments or decrements the duty cycle automatically and cyclically after a single push
according to the previous PWM duty cycle up or down event. 20
18
ILED (mA)
16
14
12
10
8
6
4
2
0
100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5
PWM Duty Cycle (%)
Figure 5: Filtered PWM Dimming Duty Cycle vs. Maximum LED Current
(20mA max) on the AAT1401IUQ Evaluation Board.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202315A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 29, 2012
5
EVALUATION BOARD DATA SHEET
EV174
Evaluation Board for the AAT1401
Serial LED Driver with Filtered PWM and 32-Step S2C Dimming Control
User Interface Functionality
Button(s)
Control
SC
2
UP
S2C+PWM
S2C
DOWN
S2C+PWM
CYCLE
S2C
S C+PWM
S2C
2
UP+DOWN+CYCLE
Description
[Push/Release once]: Increment the number of EN/SET edge; Toggles through the available
dimming level settings for the backlighting section.
[Push Hold 0.6 sec.+ ]: Auto-increment the number of EN/SET edges up to 32 then wrap back
to 1.
[Push/Release once]: Increment the duty cycle.
[Push Hold 0.6 sec.+ ]: Auto-increment the duty cycle from 5% to 100% in 5% steps then
wrap back to 5%.
[Push/Release once]: Decrement the number of EN/SET edge; Toggles through the available
brightness level settings for the backlighting section.
[Push Hold 0.6 sec.+ ]: Auto-decrement the number of EN/SET edges down to 1 then wrap
back to 32.
[Push/Release once]: Decrement the duty cycle.
[Push Hold 0.6 sec.+ ]: Auto-decrement the duty cycle from 100% to 5% in 5% steps then
wrap back to 100%.
Auto-cycling.
Auto-cycling.
Shut down.
Table 1: User Interface Functionality.
Test Waveform
Operation Waveform
Figure 6 shows the operation waveform under code 5 via S2Cwire control at 3.6V VIN; Figure 7 shows the operation
waveform under PWM control with 60% duty cycle after setting the 20mA max current by S2Cwire control at 3.6V VIN.
Ch1: PWM; Ch2: IIN; Ch3: ILED; Ch4: VOUT
Ch1: EN/SET; Ch2: IIN; Ch3: ILED; Ch4: VOUT
Figure 6: Waveform Controlled by S2Cwire.
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Figure 7: Waveform Controlled by Filtered PWM.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202315A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 29, 2012
EVALUATION BOARD DATA SHEET
EV174
Evaluation Board for the AAT1401
Serial LED Driver with Filtered PWM and 32-Step S2C Dimming Control
Startup
Figure 8 shows the AAT1401 startup waveform after adding one rising edge on EN/SET. Soft start control makes the
input current rise slowly.
Ch1: SW; Ch2: IIN; Ch3: ILED; Ch4: VOUT
Figure 8: Startup Waveform at 20mA LED Current.
Printed Circuit Board
a: Top Layer (not to scale)
(b) Bottom Layer (not to scale)
Figure 9: AAT1401IUQ Evaluation Board.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202315A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 29, 2012
7
EVALUATION BOARD DATA SHEET
EV174
Evaluation Board for the AAT1401
Serial LED Driver with Filtered PWM and 32-Step S2C Dimming Control
AAT1401IUQ EVAL Component Listing
Component
Part Number
Description
Manufacturer
U1
U2
R1
R2, R3, R4, R6
RSET
R5, R7, R8, R9
CIN
COUT
C1
Ccom
D1, D2, D3, D4, D5, D6
DS1
L1
LED1
CYCLE, UP, DOWN
AAT1401IUQ
PIC12F675
RC0603FR-071ML
RC0603FR-0751KL
RC0603FR-0715KL
RC0603FR-071KL
GRM188R60J475K
GRM18BR71H104K
GRM188R71C104K
GRM188R71C563K
RS-0805UW
SDM20U40
CDRH3D18-100NC
0805KRCT
6*6*5
High Efficiency Serial LED Driver for 6 White LEDs
8-Pin Flash-Based 8-Bit CMOS Microcontrollers
Res 1MΩ 1/10W 1% 0603 SMD
Res 51KΩ 1/10W 1% 0603 SMD
Res 15KΩ 1/10W 1% 0603 SMD
Res 1KΩ 1/10W 1% 0603 SMD
Cap Ceramic 4.7μF 0603 X5R 6.3V 10%
Cap Ceramic 0.1μF 0603 X7R 50V 10%
Cap Ceramic 0.1µF 0603 X7R 16V 10%
Cap Ceramic 0.056µF 0603 X7R 16V 10%
20mA White LED 0805
Surface Mount Schottky Barrier Diode
Power Inductor 10μH 0.9A SMD
Red LED 0805
12V 50mA Pushbutton
Skyworks
Microchip
Yageo
Murata
Realstar
Diode
Sumida
HB
E-LT
Table 4: AAT1401IUQ Evaluation Board Bill of Materials.
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.
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202315A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 29, 2012