原标题：Infineon TLD5542－1带SPI接口的H桥DC－DC转换器解决方案

　　infineon公司的TLD5542-1是内置了保护特性和SPI接口的同步MOSFET H桥DC/DC转换器,具有能以最大系统效率和最少外接元件来驱动大功率LED的优势. TLD5542-1提供模拟和数字(PWM)调光.开关频率在200kHz到700kHz可调,并和外部时钟源同步.内置的可编扩展频谱开关频率调制器和强迫连续电流调整模式改善了整个EMC性能.此外,电流模式调整方案提供由小型外接补偿元件所维持的稳定调节回路.可调软起动特性限制了起动时电流峰值和电压过冲值. TLD5542-1是单电感大功率降压-升压控制器,LED正向电压从2V到高达55V,SPI接口用于诊断和控制,每种条件的最大效率高达96%.器件也适合用在苛刻的汽车环境.由于快速输出放电工作,用单个IC能驱动多个负载.LED电流的精度+/- 3%.对器件和负载都有先进的保护特性.主要用在驱车多个大功率LED的特别设计,汽油外部照明以及通用DC/DC电压稳压器.本文介绍了TLD5542-1主要特性,框图和多种应用框图, 评估板TLD5542-1IVREG-EVAL主要特性和电特性,电路图和PCB设计图.

　　The TLD5542-1 is a synchronous MOSFET H-Bridge DC/DC controller with built in protection features and SPI interface. This concept is beneficial for driving high power LEDs with maximum system efficiency and minimum number of external components. The TLD5542-1 offers both analog and digital (PWM) dimming. The switching frequency is adjustable in the range of 200 kHz to 700 kHz. It can be synchronized to an external

　　clock source. A built in programable Spread Spectrum switching frequency modulation and the forced continuous current regulation mode improve the overall EMC behavior. Furthermore the current mode regulation scheme provides a stable regulation loop maintained by small external compensation components. The adjustable soft start feature limits the current peak as well as voltage overshoot at start-up.

　　The TLD5542-1 is suitable for use in the harsh automotive environment.

　　TLD5542-1主要特性:

　　• Single inductor high power Buck-Boost controller

　　• Wide LED forward voltage range (2 V up to 55 V)

　　• Wide VIN range (IC 4.5 V to 40 V, power 4.5 V to 55 V)

　　• Switching frequency range from 200 kHz to 700 kHz

　　• SPI for diagnostics and control

　　• Maximum efficiency in every condition (up to 96%)

　　• Constant current (LED) and constant voltage regulation

　　• Drives multiple loads with a single IC thanks to the Fast Output Discharge operation

　　• Limp Home function (fail safe mode)

　　• EMC optimized device: features an Auto Spread Spectrum

　　• LED and input current sense with dedicated monitor outputs

　　• Advanced protection features for device and load

　　• Enhanced dimming features: Analog and PWM dimming

　　• LED current accuracy +/- 3%

　　• Available in a small thermally enhanced PG-VQFN-48 or PG-TQFP-48 package

　　• Automotive AEC Qualified

　　保护功能:

　　• Over load protection of external MOSFETs

　　• Shorted load, output overvoltage protection

　　• Input undervoltage protection

　　• Thermal shutdown of device with autorestart behavior

　　• Electrostatic discharge protection (ESD)

　　诊断功能:

　　• Latched diagnostic information via SPI

　　• Device Overtemperature shutdown and Temperature Prewarning

　　• Smart monitoring and advanced functions provide ILED and IIN information

　　跛行模式功能:

　　• Limp Home activation via LHI pin

　　TLD5542-1应用:

　　• Especially designed for driving multiple high power LED functions (I.E. Low Beam, High Beam, DRL)

　　• Automotive Exterior Lighting: full LED headlamp assemblies

　　• General purpose DC/DC voltage regulator

　　图1. TLD5542-1框图

　　图2. TLD5542-1应用电路:电流调整器

　　图3. TLD5542-1调整器框图

　　图5. TLD5542-1应用电路:增加元件以改善EMC性能

　　图6. TLD5542-1应用电路:3功能LED驱动器模块

　　TLD5542-1用作电流调整器的材料清单(BOM):( I OUT=1A,fSW=300kHz)

　　图7. TLD5542-1应用电路:可调整电压稳压器

　　TLD5542-1用作电压调整器的材料清单(BOM):

　　评估板TLD5542-1IVREG-EVAL

　　The TLD5542-1IVREG-EVAL is an evaluation platform for the TLD5542-1, which can work as buck-boost LED driver, or as a voltage regulator.

　　The H-Bridge architecture is among the most efficient buck-boost topologies for high current applications. The TLD5542-1 provides complete control and diagnostics through the SPI interface.

　　The device can be used in microcontroller-less applications, because of the limp home mode.

　　The TLD5542-1IVREG-EVAL is an evaluation platform for the TLD5542-1 as LED driver or voltage regulator.

　　The default configuration is constant current LED driver with 1.5 A maximum output current. The output current can be increased up to 6A by changing RSHO. If higher currents are needed, the output filter has to be bypassed.

　　图8. 评估板TLD5542-1IVREG-EVAL外形图