2.4V LED Driver with Independent Analog and PWM Dimming Controls of 2 Backlights for 3D Application ISL97691 Features The ISL97691 is Intersils highly integrated 4 channel LED driver 2.4V Minimum input voltage, no need for higher voltage for single cell Li-Ion battery operated mobile displays requiring supplies analog dimming, and for 3D mobile display applications. It drives 4 x 60mA (Note 1) and 4 x 40mA (Note 2) LED current four 40mA channels of LEDs up to 26V from an input supply 2.4V 2 Groups of independent analog and pwm current controls to 5.5V. The ISL97691 will also drive 60mA channels up to 21V at - 1-Wire interfaces for 6-bit analog dimming 30% duty for high peak current 3D modes. - PWM inputs for PWM dimming The ISL97691 provides 4 channels of current with 2 independent - 0.005% Minimum PWM dimming duty cycle at 100Hz analog dimming controls and 2 independent PWM dimming controls. Channels 1 and 2 form one channel group and channels Low 0.8mA quiescent current 3 and 4 form the other channel group. Each channel groups 2.5% current matching analog dimming is controlled through 1-Wire communication with 6-bit resolution and each channel groups PWM dimming is Adjustable switching frequency from 400kHz to 1.5MHz controlled by a separate PWM input. This unique setup allows 2D Fault protection or 3D application where independent and dynamic channel - OVP, OTP, channel open/short circuit protections control of LED peak current and PWM dimming duty cycle are possible. The ISL97691 employs adaptive boost architecture that Applications allows ultra low dimming duty cycle as low as 0.005% at 100Hz Tablet, notebook PC and smart phone displays LED dimming frequency. backlighting The driver features dynamic headroom control that monitors the Mobile displays for 2D or 3D LED backlighting highest LED forward voltage string and uses its feedback signal for the minimum output regulation. The ISL97691 incorporates extensive protection functions NOTES: including string open and short circuit detections, OVP, and OTP. 1. Not exceeding 30% of the frame rate (1/t ), with V > 2.7V and The switching frequency can be adjusted from 400kHz to 1.5MHz. FRAME IN T < +55C. The device is offered in a 16 Ld TQFN 3x3mm package and can A 2. V > 2.7V operate in ambient temperature from -40C to +85C. IN I L1 D1 V = 24.5V, 4 x 60mA* V = 2.7V~5.5V OUT IN 10H 4.7F 4.7F 4.7F 10 VIN 1F 100pF LX 10 470k COMP OVP 15nF 23.7k 2.2nF 12k 1 ISL97691 ISET 17.8k PGND 0.1 AGND 1-WIRE 1 0.01 CH1 1-WIRE 2 CH2 PWM2 f : 200Hz PWM CH3 0.001 PWM 1 f : 100Hz CH4 PWM FSW *NOT EXCEEDING 30% PWM DUTY 143k 0.0001 0.001 0.01 0.1 1 10 INPUT DIMMING DUTY CYCLE (%) FIGURE 1. TYPICAL APPLICATION CIRCUIT FIGURE 2. ULTRA LOW PWM DIMMING LINEARITY February 1, 2013 CAUTION: These devices are sensitive to electrostatic discharge follow proper IC Handling Procedures. 1 1-888-INTERSIL or 1-888-468-3774 Copyright Intersil Americas LLC 2012, 2013. All Rights Reserved FN7840.1 Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. ILED (mA)ISL97691 Block Diagram UP TO 26V V = 2.4V~5.5V IN 10H VIN LX 2X4.7F ISL97691 O/P SHORT REG INTERNAL BIAS OVP OVP OSC & FSW RAMP PWM/ FET S = 0 COMP PFM DRIVERS LOGIC IMAX ILIMIT PGND OPEN CKT, SHORT CKT DETECTION COMP DYNAMIC CH1 GM HIGHEST 8-BIT HEADROOM AMP CH2 VF STRING DAC CONTROL CH3 DETECT CH4 DC1 6-BIT 1 + DAC - + REF - PWM1 GEN ISET 2 + - REF REF OVP VSC DC2 1-WIRE 1 6-BIT 1-WIRE I/F 3 + 1-WIRE 2 DAC - PWM2 PWMI 1 PWM DIMMING TEMP 4 + CONTROLLER PWMI 2 - SENSOR Ordering Information PART NUMBER PART TEMP RANGE PACKAGE PKG. (Notes 3, 4, 5) MARKING (C) (Pb-free) DWG. ISL97691IRTZ 7691 -40 to +85 16 Ld TQFN L16.3x3D ISL97691IRTZ-EVALZ Evaluation Board NOTES: 3. Add -T* suffix for tape and reel. Please refer to TB347 for details on reel specifications. 4. These Intersil Pb-free plastic packaged products employ special Pb-free material sets molding compounds/die attach materials and 100% matte tin plate - e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 5. For Moisture Sensitivity Level (MSL), please see device information page for ISL97691. For more information on MSL please see techbrief TB363. FN7840.1 2 February 1, 2013