原标题：TI PMP20249双路汽车12.5W USB充电器参考设计

　　TI公司的PMP20249是EMI优化的双路汽车12.5W USB充电器参考设计,采用LMS3635和LMS3655稳压器以及TPS2549 USB开关,具有CISPR 25 Class 4设计额定值;输入电压从6Vin到18Vin,2.5A时输出电压5V,主要用在汽车USB充电系统和汽车娱乐系统.本文介绍了参考设计PMP20249主要特性和指标,框图,电路图,材料清单和PCB设计图.

　　PMP20249 is an EMI-optimized design for dual-automotive USB charger system using the LMS3635 andLMS3655 regulators (400-kHz fully-integrated, synchronous buck for automotive applications) and theTPS2549 USB switch (TPS2549-Q1 automotive USB charging port controller with integrated power switchand cable compensation). The design accepts an input voltage range of 6 Vin to 18 Vin and regulates twooutputs of 5 V at 2.5 A for dual-USB ports. This highly efficient design features an inexpensive solution and small-size customized for an automotive USB charger application. A four-layer PCB was used for thisdesign.

　　The design is divided into four major blocks:

　　• Front-end protection: Front-end protection against positive and negative pulses (ISO7630 pulse 1, 2a,3a/b) through TVS.

　　• EMI filter: Differential filter for conducted EMI suppression.

　　• Low-EMI front-end DC-DC converters: LMS3655-Q1 and LMS3635-Q1 are switching, synchronous5.5-A and 3.5-A buck regulators, and in this design the devices are used as front-end DC-DCconverters. These 400-kHz parts are automotive optimized and have low EMI. The device comes in anautomotive-qualified HotRod™ QFN package with wettable flanks, which reduces parasitic inductanceand resistance while increasing efficiency, minimizing switch node ringing, and dramatically loweringEMI. The spread spectrum feature is a factory option which further reduces EMI. This featureeliminates peak emissions at specific frequencies by spreading emissions across a wider range of frequencies.

　　• Downstream USB charging-port controller and power switch: TPS2549-Q1 maintains 5 V at the USBport during heavy charging currents.

　　参考设计PMP20249主要特性:

　　• Wide-Vin Front-End Power Supply for USBCharger System

　　• Off-Battery Operation With Positive and NegativeOvervoltage Protection

　　• Passed CISPR 25 Class 4 Conducted EMI Test

　　• Switching Frequency: Outside AM Band (400 kHz)for all Converters

　　• All AEC-Q100-Qualified Devices

　　• Supports 6-V to 18-V Wide-Vin Range

　　描述

　　PMP20249 是一种 EMI 优化设计，适用于使用 LMS3635 和 LMS3655 稳压器 IC(适用于汽车应用的 400kHz 完全集成的同步降压稳压器)和 TPS2549 USB 开关 (带有集成电源开关和电缆补偿的 TPS2549-Q1 汽车 USB 充电端口控制器)的双路汽车 USB 充电器系统。此设计接受的输入电压范围为 6V 至 18V，并提供 5V@3.5A 和 5V@2.5A 的输出。此设计采用一个差分 EMI 滤波器，并在无屏蔽、共模扼流圈或铁氧体磁珠的情况下通过了 CISPR25 4 类传导 EMI 限制测试。

　　特性

　　宽输入电压范围前端电源，适用于具有双路 12.5W 输出的汽车 USB 充电器系统

　　具有正负过压瞬态保护的脱离电池运行模式

　　通过了 CISPR25 4 类传导 EMI 测试

　　所有器件均具有符合 AEC-Q100 认证的可用版本

　　所有器件均可在 AM 和 FM 频带外开关

　　参考设计PMP20249应用:

　　• Automotive USB Charger System

　　• Automotive Infotainment System

　　图1.参考设计PMP20249外形图

　　参考设计PMP20249主要指标:

　　参考设计PMP20249材料清单:

　　详情请见:

tidrsl4.pdf.pdf

tidrsl3.pdf.pdf

tidrsl6.pdf.pdf

tiducu2.pdf.pdf