SKY81298_PS_203693A.pdf

PRODUCT SUMMARY
SKY81298: 2.4 A Three-Channel Flash LED Driver
with I2C Control Interface
Applications
Description
 LED photo flash with Movie/Torch mode
The SKY81298 is a high-efficiency, high-current boost converter
with three independently programmable constant current outputs.
The device is optimized for LED flash applications implementing
tri-tone flash LED color compensation, or dual rear LED flash plus
single front LED flash to support “selfie” pictures taken from the
front-facing camera. The SKY81298 uses a single DC/DC boost
and only one inductor to support all three LED outputs, and all
LED outputs may be enabled simultaneously to support up to a
total of 2.4 A total LED current.
 Tri/dual tone LED for color compensation
 “Selfie” flash for front-facing camera (PIP enabled)
 Smartphones/tablets
Features
 Input voltage range: 2.5 V to 5.5 V
 Each channel can program up to 1.5 A with 12 mA step size;
up to 2.4 A total combined output current
 > 90% LED efficiency at 250 mA (3.3 V < VIN < 3.6 V,
VF = 3.3 V);
> 85% LED efficiency at 1 A (3.4 V< VIN < 3.9 V, VF = 3.3 V)
 2.75 MHz switching frequency
 Soft-start and input current limit
 Separate flash enable/flash inhibit
 Programmable blinking LED notification
 Industry standard 1 MHz I2C programming
 Flash and Movie mode current
 Input voltage monitor with programmable thresholds
 Current read-back in input voltage monitor operation
 Programmable safety timer
 Fault read back
 Fault protection
 Integrated safety timer
 Over-voltage (open LED, open circuit)
 Short circuit
 Over-temperature protection
 Flash mode input voltage monitor
 Open-drain fault output
The SKY81298 maintains the flash LED output current using a
DC-DC step-up converter with a bypass function to maximize
efficiency under all load conditions. The flash current for each
channel can be programmed up to 1.5 A at 12 mA step. The
device uses a common cathode (current source) topology to allow
a direct flash LED cathode connection to the ground plane which
facilitates LED heat dissipation. The total combined output current
for flash outputs is 2.4 A.
The high-frequency 2.75 MHz DC-DC boost switching frequency
allows the use of a small external inductor and output capacitor,
which makes the SKY81298 ideally suited for small batterypowered applications. A startup control circuit automatically
senses the flash LED forward voltage at any programmed output
current setting and determines the most efficient operation mode.
An industry standard I2C digital interface is used to program the
SKY81298 LED Flash and Movie modes. Device operations are
fully configurable; Movie and Flash current level, current limits,
and fault reporting are managed through I2C. Also included are
separate flash enable inputs to initiate the flash operation and a
flash inhibit input either to reduce the flash current to Moviemode levels or to shut off the flash current during high battery
demand conditions. The flash enable inputs can be configured to
control different flash LEDs as required by the system designer.
 Temperature range: −40 C to +85 C
The SKY81298 is available in a small 1.903  1.903  0.605 mm,
16-bump Wafer-Level Chip Scale (WLCSP) package.
 Small WLCSP (16-bump, 1.903  1.903  0.605 mm, 0.4 mm
pitch) package (MSL1, 260 C per JEDEC J-STD-020)
The typical application circuits are shown in Figures 1a and 1b.
Skyworks GreenTM products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of GreenTM, document number
SQ04–0074.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
203693A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • August 31, 2015
1
PRODUCT SUMMARY • SKY81298: 2.4 A THREE-CHANNEL FLASH LED DRIVER WITH I2C CONTROL INTERFACE
L1
1.0 µH
SW
IN
VIN
OUT
CIN
4.7 µF
COUT
4.7 µF
SKY81298
Device Enable
EN
I2C Serial Data Input
I C Serial Clock Input
FL1
FL2
FL3
SDA
SCL
2
Flash 1 Enable
Flash 2 Enable
Flash Inhibit
White LED
(can be used
as indicator)
FLEN 1
FLEN 2
FLINH
White
Flash LED
Amber
Flash LED
Selfie Flash/Indicator
GND
PGND
Dual Rear Flash
t0691
Figure 1a. SKY81298 Typical Application Diagram for Dual Rear Flash and Front Selfie Flash
L1
1.0 µH
SW
IN
VIN
OUT
CIN
4.7 µF
COUT
4.7 µF
SKY81298
Device Enable
I2C Serial Data Input
I C Serial Clock Input
2
Flash 1 Enable
Flash 2 Enable
Flash Inhibit
FL1
FL2
FL3
EN
SDA
SCL
Amber
Flash LED
Neutral
Flash LED
White
Flash LED
FLEN 1
FLEN 2
FLINH
GND
PGND
Tri-Tone Rear Flash
t0692
Figure 1b. SKY81298 Typical Application Diagram for Tri-tone Rear Flash
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
2
August 31, 2015 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 203693A
PRODUCT SUMMARY • SKY81298: 2.4 A THREE-CHANNEL FLASH LED DRIVER WITH I2C CONTROL INTERFACE
Ordering Information
Model Name
Total Output Current
With VIN Monitor Function
With Blinking Function
Manufacturing Part Number
SKY81298-11
2.4 A
Yes
Yes
SKY81298-11-001
SKY81298-12
2.4 A
Yes
No
SKY81298-12-001
SKY81298-13
2.4 A
No
Yes
SKY81298-13-001
SKY81298-14
2.4 A
No
No
SKY81298-14-001
SKY81298-21
2A
Yes
Yes
SKY81298-21-001
SKY81298-22
2A
Yes
No
SKY81298-22-001
SKY81298-23
2A
No
Yes
SKY81298-23-001
SKY81298-24
2A
No
No
SKY81298-24-001
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
203693A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • August 31, 2015
3