Linear 公司的LT3597是 60V三路降壓LED驅動器,在100Hz時可提供10000:1數字PWM調光,每路可驅動多達10個LED,開關頻率可在200kHz和1MHz間編程,自適應控制輸出以得到最佳效率,通路間的LED電流匹配2%,開路LED報告,短路LED保護,可編程LED電流和可編程溫度保護. LT3597可用在LED信號板,單色,多色和滿色LED顯示器,大屏幕顯示LED背光以及汽車,工業和醫療顯示器.本文介紹了LT3597主要特性, 方框圖以及多種應用電路圖.
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應用:
LED Billboards and Signboards
Mono, Multi, Full-Color LED Displays
Large Screen Display LED Backlighting
Automotive, Industrial, and Medical Displays
圖1.LT3597方框圖
圖2.LT3597三路RGB單像素100mA LED驅動電路圖
圖3.LT3597 48V 1MHz降壓100mA RGB LED驅動電路圖
圖4.LT3597 48V 1MHz降壓10W 100mA RGB LED驅動電路圖(3.6V LED)
圖5.LT3597 24V 200kHz三路降壓100mA RGB LED驅動電路圖
圖6.LT3597 48V 1MHz三路降壓20mA RGB LED驅動電路圖
詳情請見:
http://cds.linear.com/docs/Datasheet/3597f.pdf
