TI LP8863－Q1带升压控制器汽车高效LED驱动方案 |电子通-应用新知，新电子的助推者电子通

TI公司的LP8863-Q1是带升压控制器汽车高效LED驱动器,有六个高精度支持相移的电流沉,通过SPI或I2C接口根据所用的路数单独控制电流沉的亮度,电流精度1%,调光比为32000:1,采用SPI,I2C或PWM输入高达16位LED调光分辨率.满足汽车应用规范AEC-Q100,工作温度–40℃ 到+125℃ ,输入电压3V-48V.主要用在汽车背景光如汽车信息娱乐系统,汽车仪表盘,智能后视镜,抬头显示器 (HUD),中央信息显示屏 (CID)和音视频导航 (AVN).本文介绍了LP8863-Q1主要特性,功能框图和应用电路,以及LED驱动器汽车应用评估模块LP8863-Q1 EVM特性,包括LED负载板的电路图,材料清单和PCB设计图.

The LP8863-Q1 is an automotive high-efficiency LEDdriver with boost controller. The six high-precisioncurrent sinks support phase shifting that isautomatically adjusted based on the number ofchannels in use. Current sink brightness can becontrolled individually and globally through the SPI orI2C interface; brightness can also be globallycontrolled with PWM input.

The boost controller has adaptive output voltagecontrol based on the headroom voltages of the LEDcurrent sinks. This feature minimizes the powerconsumption by adjusting the voltage to the lowestsufficient level in all conditions. A wide-rangeadjustable frequency allows the LP8863-Q1 to avoiddisturbance for AM radio band.

The LP8863-Q1 supports built-in hybrid PWM andcurrent dimming, which reduces EMI, extends theLED lifetime, and increases the total opticalefficiency.

LP8863-Q1主要特性:

1• Qualified for Automotive Applications
• AEC-Q100 Qualified With the Following Results:
– Device Temperature Grade 1:–40℃ to+125℃ Ambient Operating Temperature
• Input Voltage Operating Range 3 V to 48 V
• Six High-Precision Current Sinks
– Current Matching 1% (typical)
– Dimming Ratio 32 000:1 Using 152-Hz LEDOutput PWM Frequency
– Up to 16-bit LED Dimming Resolution WithSPI, I2C, or PWM Input
– Automatically Detects Used LED Strings andAdjusts LED-Channel Phase Shift
– Independent Current Control for Each Channel
• Hybrid PWM and Current Dimming Function
• Up to 47-V VOUT Boost or SEPIC DC-DCController
– Switching Frequency 300 kHz to 2.2 MHz
– Boost Spread Spectrum for Reduced EMI
– Boost Sync Input to Set Boost SwitchingFrequency From an External Clock
– Integrated Charge Pump Supports Low VINConditions Such as Cold Crank
– Output Voltage Automatically DischargedWhen Boost is Disabled.
• Extensive Fault Diagnostics

LP8863-Q1应用:

• Backlight for:
– Automotive Infotainment
– Automotive Instrument Clusters
– Smart Mirrors
– Heads-Up Displays (HUD)
– Central Information Displays (CID)
– Audio-Video Navigation (AVN)

图1.LP8863-Q1功能框图

图2.LP8863-Q1简化应用电路图

图3.LP8863-Q1显示器背景光全特性应用电路图

图4.LP8863-Q1三列LED串联SEPIC模式应用电路图

图5.LP8863-Q1SEPIC模式应用主要元件电路图

LED驱动器汽车应用评估模块LP8863-Q1 EVM

This user’s guide describes the module used to evaluate characteristics, operation, and use of theLP8863-Q1 automotive LED backlight driver. This document includes a schematic diagram, PCB layout,and bill of materials (BOM).

TI’s LP8863-Q1 evaluation module (EVM) helps designers evaluate the operation and performance of theLP8863-Q1 automotive LED backlight driver. The device offers configurability and can be set up throughexternal resistor options for boost switching frequency, LED current, and PWM out frequency.Internalregister options enable various controls such as brightness inputs, slope control, dimming options, etc.

The EVM contains one LP8863-Q1 LED driver with boost circuit and a Tiva Launchpad evaluation circuitto provide control signals for LED driver.
<IMG style="WIDTH: 413px; HEIGHT: 310px" LED driver Evaluation Module Board Photo" src="http://upload.cdn.oneyac.com/upload/maket_res/news_res/2018_07_24/g14vwrrflf4.jpg" alt="TI LP8863－Q1带升压控制器汽车高效LED驱动方案" width=350 height=225>
图6.评估模块LP8863-Q1 EVM外形图