原标题：Linear LT3597 60V三路降压LED驱动方案

　　Linear 公司的LT3597是 60V三路降压LED驱动器,在100Hz时可提供10000:1数字PWM调光,每路可驱动多达10个LED,开关频率可在200kHz和1MHz间编程,自适应控制输出以得到最佳效率,通路间的LED电流匹配2%,开路LED报告,短路LED保护,可编程LED电流和可编程温度保护. LT3597可用在LED信号板,单色,多色和满色LED显示器,大屏幕显示LED背光以及汽车,工业和医疗显示器.本文介绍了LT3597主要特性, 方框图以及多种应用电路图.

　　The LTR3597 is a 60V triple step-down LED driver capable of achieving 10,000:1 digital PWM dimming at 100Hz with fast NPN current sources driving up to 10 LEDs in each channel. LED dimming can also be achieved via analog control of the CTRL1-3 pin.

　　The step-down switching frequency is programmed between 200kHz and 1MHz. The frequency is also synchronizable to an external clock. The LT3597 provides maximum LED brightness while adhering to manufacturers’ specifications for thermal derating. The derate temperature is programmed by placing a negative temperature coefficient (NTC) resistor on the master control pin.

　　The LT3597 adaptively controls VOUT in order to achieve optimal efficiency. Other features include: 2% LED current matching between channels, open LED reporting, shorted LED protection, programmable LED current, and programmable temperature protection.

　　LT3597主要特性:

　　Three 100mA Buck Regulators, Each Drives Up to 10 LEDs with Fast NPN Current Sources

　　Fast Current Sources for <1μs Pulse Widths (10,000:1 True Color PWM™ Dimming at 100Hz)

　　LEDs Disconnected in Shutdown

　　Adaptive VOUT for Increased Efficiency

　　6V to 60V Input Voltage Range

　　±2% LED Current Matching

　　External Resistor Sets LED Current for Each Channel

　　Internal Compensation and Soft-Start

　　Programmable Switching Frequency (200kHz to 1MHz)

　　Synchronizable to External Clock

　　Open LED Detection and Reporting

　　Shorted LED Pin Protection and Reporting

　　Programmable LED Thermal Derating

　　Programmable Temperature Protection

　　5mmx 8mm Thermally Enhanced QFN Package with a 0.6mm High Voltage Pin Spacing

　　LT3597应用:

　　LED Billboards and Signboards

　　Mono, Multi, Full-Color LED Displays

　　Large Screen Display LED Backlighting

　　Automotive, Industrial, and Medical Displays

　　图1.LT3597方框图

　　图2.LT3597三路RGB单像素100mA LED驱动电路图

　　图3.LT3597 48V 1MHz降压100mA RGB LED驱动电路图

　　图4.LT3597 48V 1MHz降压10W 100mA RGB LED驱动电路图(3.6V LED)

　　图5.LT3597 24V 200kHz三路降压100mA RGB LED驱动电路图

　　图6.LT3597 48V 1MHz三路降压20mA RGB LED驱动电路图