- 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
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.
- WLED backlit LCD displays for Smartphones, digital cameras, GPS, etc.
|# of Devices/ Channels||2||4||6||1|
|Total Current for DC/DC Lighting||50 mA||240 mA||180 mA||40 mA|
|Output Current Max/Channel||25 mA||60 mA||30 mA||40 mA|
|VOUT (max) (V)||23.5||21||26||27|
|Brightness Control||Yes||Yes||Yes||PWM DC to 32kHz|
|VIN (max) (V)||5.5||5.5||5.5||5.5|
|VIN (min) (V)||2.5||2.4||2.4||2.4|
|Backlight for LCD Size (min)||0 in||0 in||0 in||1.8 in|
|Backlight for LCD Size (max)||5 in||17 in||17 in||3.5 in|
|Peak Efficiency (%)||91||90||90||85|
|# of LEDs (max)||2-channel 23.5V 25mA LED Driver||4-channel 21V 60mA LED Driver||6-channel 26V 30mA LED Driver||7|
|Frequency||0.460 to 1.5 MHz||400kHz to 1.5 MHz||0.4, 1.2, 1.5 MHz||1.4 MHz|
|IQ (max)||350 µA||1 mA||1 mA||1 µA|
|ISW (typ)||1100 mA||2800 mA||2800 mA||470 mA|
|Over Voltage Protection||Yes||Yes||Yes||Yes|
|Topologies||Inductor Boost||Inductor Boost||Inductor Boost||Inductor Boost|