ISL97698 Datasheet, PDF (1/22 Pages) Intersil Corporation – High Efficient 2-Channel White LED Driver for Smartphone Backlighting

High Efficient 2-Channel White LED Driver for
Smartphone Backlighting
ISL97698
The ISL97698 is a highly integrated 2-channel LED driver for
white LED (WLED) backlit TFT-LCD panels. The device is
comprised of a synchronous boost converter and two low-side
current sinks that are capable of driving an output voltage up
to 23.5V and 25mA LED current, per string. The IC operates
from an input supply of 2.5V to 5.5V.
The driver features Dynamic Headroom Control that monitors
the highest LED forward voltage string to determine the
requested boost output voltage. With a controlled low 70mV
headroom voltage and low 0.35mA IC supply current, the
device provides very high efficiency.
The ISL97698 offers 8-bit linear or 11-bit logarithmic
controlled analog output current, with dimming control from a
PWM, SWIRE, or I²C interface. Internally, the PWM duty cycle,
SWIRE, and I²C digital inputs are converted to a DC LED
current. This analog dimming scheme provides high efficiency
and eliminates audible noise and PWM dimming related EMI
concerns. The ISL97698 also features Content Adaptive
Backlight Control (CABC), which uses the product of the PWM
and SWIRE, or PWM and I²C, or SWIRE and I²C inputs to
determine the LED string current. The I²C interface is also
used for configuration settings and fault detection. The
ISL97698 incorporates various protections including: open
circuit, short circuit, and thermal shutdown.
The device is offered in a 1.39mmx 1.69mm, 3x4 array
WLCSP package. It is specified for operation over the -40°C to
+85°C ambient temperature range.
Features
• High Efficiency Operation:
- Up to 91% with 2P4S configuration
- Up to 90% with 2P6S configuration
• Extremely Low Supply Current (0.35mA)
• Dynamic Headroom Control
- Very low headroom voltage (70mV)
• 20mm² Total Solution PCB Area
- Only three external components required
• Analog Dimming Control by PWM, SWIRE, or I²C
• 8-bit Linear or 11-bit Logarithmic Analog Output Current
Control
• Content Adaptive Backlight Control (CABC)
• Input Voltage from 2.5V to 5.5V
• 23.5V Maximum Output Voltage
• Drives 50µA to 25mA LED Strings
• Open Circuit and Short Circuit Fault Protection
• 12 Bump, 0.4mm Pitch Chip Scale Package
Applications
• WLED backlit LCD displays for Smartphones, digital
cameras, GPS, etc.
VIN
2.5V to 5.5V
C_IN
L
10 µH
VIN
SCL
SDA
PWMI
SWIRE
VIN_ IO
EN
ISL 97698
LX
VOUT
VOUT
Up to 23.5V
C_OUT
3.3µF
GND
CH0
CH1
September 5, 2013
FN8417.0
FIGURE 1. ISL97698 TYPICAL APPLICATION CIRCUIT: TFT-LCD BACKLIGHT
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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