Maxim MAX20446B带混合调光和I2C接口的6路背景光驱动方案

Maxim公司的MAX20446B是带升压/SEPIC控制器,混合调光和I2C接口的6路背景光驱动器,每路电流输出可沉入高达130mA LED电流.器件的输入电压从4.5V到36V,能经受住汽车负载突降的影响.MAX20446B内部电流模式开关DC/DC控制器支持升压或SEPIC拓扑,工作频率从400kHz到2.2MHz.集成的扩频有助于降低EMI.自适应的输出电压控制方案最小化LED电流沉入通路的功耗.器件具有I2C控制的脉宽调制(PWM)调光和混合调光.LED串的可选择相移调光可降低EMI.采用混合调光的调光比大于10000:1,200Hz时采用PWM调光时调光比为10000:1.器件工作温度-40 到 +125C,采用4mm x 4mm 24引脚TQFN封装.主要用在汽车娱乐显示,中心信息显示和仪表盘.本文介绍了MAX20446B主要特性和优势,功能框图,应用电路图以及评估板MAX20446B EVK主要特性,电路图,材料清单和PCB设计图.

 The MAX20446B is a 6-channel backlight driver with boost controller for automotive displays. The integrated current outputs can sink up to 130mA LED current each. The de­vice accepts a wide 4.5V to 36V input voltage range and withstands automotive load-dump events.

The internal current-mode-switching DC-DC controller supports boost or SEPIC topologies, and operates in the 400kHz to 2.2MHz frequency range. Integrated spread spectrum helps reduce EMI. An adaptive output-voltage-control scheme minimizes power dissipation in the LED current-sink paths.

The device features I2C-controlled pulse-width-modula­tion (PWM) dimming and hybrid dimming. In either case, the minimum pulse width is 500ns. Optional phase-shifted dimming of the strings is incorporated for lower EMI.

Comprehensive diagnostic information is also available through the I2C interface.

The device is available in a 24-pin TQFN package and op­erates over the -40 to +125C temperature range.

MAX20446B主要特性和优势:

● Wide-Voltage-Range Operation

• Operates Down to 4V Supply After Startup

• Survives Load Dump Up to 52V

● High Integration

• Complete 6-Channel Solution Including Boost Controller