原标题：Intersil ISL97691单颗锂电池4路LED驱动方案

　　Intersil公司的ISL97691是高度集成的单颗锂电池供电的4路LED驱动器,可用于需要模拟调光的手机显示器和 3D显示屏.输入电压2.4V-5.5V,提供4路40mA电流和高达26V电压,电流匹配±2.5% ,具有故障保护,主要用在平板电脑,笔记本PC和智能手机显示器LED背光,移动显示器2D或3D LED背光.本文介绍了ISL97691主要特性,方框图,典型应用电路图,PCB布局参考图和故障保护电路图.

　　The ISL97691 is Intersil’s highly integrated 4 channel LED driver for single cell Li-Ion battery operated mobile displays requiring analog dimming, and for 3D mobile display applications. It drives four 40mA channels of LEDs up to 26V from an input supply 2.4V to 5.5V. The ISL97691 will also drive 60mA channels up to 21V at 30% duty for high peak current 3D modes.

　　The ISL97691 provides 4 channels of current with 2 independent analog dimming controls and 2 independent PWM dimming controls. Channels 1 and 2 form one channel group and channels 3 and 4 form the other channel group. Each channel group’s analog dimming is controlled through 1-Wire communication with 6-bit resolution and each channel group’s PWM dimming is controlled by a separate PWM input. This unique setup allows 2D or 3D application where independent and dynamic channel control of LED peak current and PWM dimming duty cycle are possible. The ISL97691 employs adaptive boost architecture that allows ultra low dimming duty cycle as low as 0.005% at 100Hz dimming frequency.

　　The driver features dynamic headroom control that monitors the highest LED forward voltage string and uses its feedback signal for the minimum output regulation.

　　The ISL97691 incorporates extensive protection functions including string open and short circuit detections, OVP, and OTP. The switching frequency can be adjusted from 400kHz to 1.5MHz.

　　The device is offered in a 16 Ld TQFN 3x3mm package and can operate in ambient temperature from -40℃ to +85℃.

　　ISL97691主要特性:

　　• Operating Input Voltage 2.4V to 5.5V - No Need for Additional Supplies

　　• 4 x 60mA (Note 1) and 4 x 40mA (Note 2) LED Current

　　• 2 Groups of Independent Analog and PWM Current Controls

　　- 1-Wire Interfaces for 6-bit Analog Dimming

　　- PWM Inputs for PWM Dimming

　　- 0.005% Minimum PWM Dimming Duty Cycle at 100Hz

　　• Low 1mA Operating Current

　　• ±2.5% Current Matching

　　• Adjustable Switching Frequency from 400kHz to 1.5MHz

　　• Fault Protection

　　- OVP, OTP, Channel Open/Short Circuit Protections

　　ISL97691应用:

　　• Tablet, Notebook PC and Smart Phone Displays LED Backlighting

　　• Mobile Displays for 2D or 3D LED Backlighting

　　图1.ISL97691方框图

　　图2.ISL97691典型应用电路图

　　图.ISL97691简化故障保护电路图