Document
10kΩ 10kΩ 2.2kΩ 2.2kΩ I/O I/O
07445-001
Data Sheet
Backlight Driver with I/O Expander ADP5520
FEATURES
Efficient asynchronous boost converter for driving up to 6 white LEDs
2.7 V to 5.5 V input voltage range 128 programmable backlight LED current levels (30 mA
maximum) Ambient light sensing with autonomous backlight
adjustment Programmable backlight fade-in/fade-out times Programmable backlight dim and off times 8 configurable GPIO pins (input, output, up to 4 × 4 keypad) Up to 3 auxiliary LED current sinks (1 dedicated, 2 configurable) 64 programmable auxiliary LED current levels (14 mA
maximum) Programmable auxiliary LED fade-in/fade-out times Programmable auxiliary LED on and off times (allows
blinking) I2C-compatible serial interface Interrupt line for signaling an external processor (INT) Hard reset (RST) 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 driver with a user configurable I/O expander. This device fits handset applications where the flip or slider section of the phone requires backlighting, I/O signaling and detecting, auxiliary LED lighting, and keypad functions. By incorporating an I2Ccompatible serial interface and a single line interrupt, the ADP5520 significantly reduces the total number of lines required to interface with the baseband processor across the hinge flex.
TYPICAL OPERATING CIRCUIT
VBAT
1µF
I/O RAIL
1µF 4.7µH 2
1 PGND SW
21 VBAT
22 BST
23 BL_SNK CAP_OUT 20
16 VDDIO
5 SCL
ADP5520
4 SDA
3 INT
15 RST R3 R2 R1 R0 C0 C1 C2 C3 13 6 7 8 9 10 11 12
GND 19 GND 18 GND 24
CMP_IN 17
ILED 14
1µF
100nF VBAT
A BC D E FGH
VBAT
Figure 1.
The ADP5520 can detect ambient light levels and adjust the backlight brightness accordingly, resulting in extended battery operation.
Once configured, the ADP5520 is capable of controlling the flip/slider backlight intensity, on/off timing, dimming, and fading without the intervention of the main processor, which results in valuable battery power saving.
Rev. B
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ADP5520
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Features .......................................