Backlight Driver with I/O Expander Data Sheet ADP5520 FEATURES TYPICAL OPERATING CIRCUIT Efficient asynchronous boost converter for driving up to VBAT 1F 6 white LEDs 4.7H 2.7 V to 5.5 V input voltage range 1F 2 22 23 128 programmable backlight LED current levels (30 mA SW BST BL SNK 1 PGND maximum) CAP OUT 20 21 VBAT I/O RAIL Ambient light sensing with autonomous backlight 1F 16 VDDIO 19 GND adjustment 18 GND Programmable backlight fade-in/fade-out times ADP5520 5 SCL 24 GND Programmable backlight dim and off times 4 SDA 100nF 8 configurable GPIO pins (input, output, up to 4 4 keypad) 3 INT 17 CMP IN Up to 3 auxiliary LED current sinks (1 dedicated, 2 configurable) 15 RST 64 programmable auxiliary LED current levels (14 mA R3 R2 R1 R0 C0 C1 C2 C3 ILED VBAT 13 6 7 8 9 10 11 12 14 maximum) Programmable auxiliary LED fade-in/fade-out times A B C D Programmable auxiliary LED on and off times (allows E F G H VBAT blinking) Figure 1. 2 I C-compatible serial interface INT Interrupt line for signaling an external processor ( ) RST Hard reset ( ) Current limit protection Thermal overload protection Available in small 4.0 mm 4.0 mm, 24-lead LFCSP package APPLICATIONS Display backlight driver for phones that require slider or flip keypad functions with single or multiple LED indicators GENERAL DESCRIPTION The ADP5520 is a versatile single-chip, white LED backlight The ADP5520 can detect ambient light levels and adjust the driver with a user configurable I/O expander. This device fits backlight brightness accordingly, resulting in extended battery handset applications where the flip or slider section of the phone operation. requires backlighting, I/O signaling and detecting, auxiliary LED Once configured, the ADP5520 is capable of controlling the 2 lighting, and keypad functions. By incorporating an I C- flip/slider backlight intensity, on/off timing, dimming, and compatible serial interface and a single line interrupt, the fading without the intervention of the main processor, which ADP5520 significantly reduces the total number of lines results in valuable battery power saving. required to interface with the baseband processor across the hinge flex. Rev. B Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20082017 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Technical Support www.analog.com 10k 10k 2. 2k 2. 2k I/O I/O 07445-001ADP5520 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Advanced Fading (Square) ........................................................ 13 Applications ....................................................................................... 1 Advanced Fading (Cubic 1 and Cubic 2) ................................ 14 Typical Operating Circuit ................................................................ 1 Ambient Light Sensing .............................................................. 14 General Description ......................................................................... 1 Automatic Backlight Adjustment ............................................. 15 Revision History ............................................................................... 2 I/O Expansion Pins (GPIOs) .................................................... 15 Specifications ..................................................................................... 3 I/O Expansion Pins (Keypad Matrix) ...................................... 15 2 I C Timing Specifications ............................................................ 4 I/O Expansion Pins and ILED Pin (Auxiliary LED Current Sinks) ............................................................................................ 17 Absolute Maximum Ratings ............................................................ 5 Interrupt Output (INT) ............................................................. 19 Thermal Resistance ...................................................................... 5 Reset Input (RST) ....................................................................... 19 ESD Caution .................................................................................. 5 Communication Interface ............................................................. 20 Pin Configuration and Function Descriptions ............................. 6 Register Map ................................................................................... 21 Typical Performance Characteristics ............................................. 6 Detailed Register Descriptions ..................................................... 22 Theory of Operation ........................................................................ 9 Applications Information .............................................................. 34 Backlight Drive and Control ....................................................... 9 Converter Topology ................................................................... 34 Backlight Operating Levels ....................................................... 10 PCB Layout ................................................................................. 35 Backlight Maximum and Dim Settings ................................... 10 Example Circuits ............................................................................ 36 Backlight Turn On/Off/Dim ..................................................... 11 Outline Dimensions ....................................................................... 38 Automatic Dim and Turn Off Timers ..................................... 11 Ordering Guide .......................................................................... 38 Linear Backlight Fade In and Fade Out ................................... 12 Fade Override ............................................................................. 13 REVISION HISTORY 10/2017Rev. A to Rev. B 1/2010Rev. 0 to Rev. A INT RST Changes to Table 1 ............................................................................. 3 Changed nINT, nRST, and nSTNBY to , , and Changes to Table 5 ............................................................................. 6 STNBY ............................................................................ Throughout Changes to Figure 32 ...................................................................... 14 Change to Package Type Column, Table 4 .................................... 5 Updated Outline Dimensions ....................................................... 38 Changes to Figure 3 and Table 5 ..................................................... 6 Changes to Ordering Guide .......................................................... 38 Updated Outline Dimensions ....................................................... 38 Changes to Ordering Guide .......................................................... 38 7/2008Revision 0: Initial Version Rev. B Page 2 of 38