On Semi NCP632 USB过压保护方案

On Semi(安森美)公司的NCP632是带集成电流保护和高速静电放电(ESD)保护的过压保护(OVP)器件,它加强USB端口的安全性，简化便携电子产品的设计，不需要使用独立的OVP、过流保护(OCP)及瞬态电压抑制器(TVS)等元件;NCP362未面市前，设计人员仍需要采用这些元件来保护易受影响的便携设备，使其免受源于USB主设备(host)、墙式适配器、人体及不恰当的修配用零件市场的交流-直流(AC-DC)适配器的电气浪涌损伤及放电脉冲影响NCP632适合便携、电信、消费和计算系统中的USB 2.0应用.本文介绍了NCP632的主要特性,以及典型应用电路,演示板电路图和所用材料清单(BOM).

The NCP362 disconnects systems at its output when wrong VBUS operating conditions are detected at its input. The system is positive overvoltage protected up to +20 V,overcurrent protected up to 750 mA, and receives protection from ESD diodes for the high speed USB data and VBUS lines. Thanks to an integrated PMOS FET, no external device is necessary,reducing the system cost and the PCB area of the application board.

The NCP362 is able to instantaneously disconnect the output from the input if the input voltage exceeds the overvoltage threshold OVLO. Thanks to an overcurrent protection, the integrated PMOS turns off when the charge current exceeds the current limit (see options in ordering information).

The NCP362 provides a negative going flag (FLAG) output, which alerts the system that voltage, current or overtemperature faults have occurred.

In addition, the device integrates ESD diodes for VBUS and data lines which are IEC61000-4-2, level 4 compliant. The ESD diodes for D+ and D are compatible with high speed USB thanks to an ultra low capacitance of 0.5 pF.

NCP362主要特性:

Overvoltage Protection up to 20 V

Undervoltage and Overvoltage Lockout (UVLO/OVLO)

Overcurrent Protection

Transient Voltage Suppressor for VBUS Pin

Ultra Low Capacitance ESD for Data Lines

Alert FLAG Output and EN Enable Pin

Thermal Shutdown

Compliance to IEC61000-4-2 (Level 4)

Compliance Machine Model and Human Body Model

10 Lead UDFN 2x2.5 mm Package

This is a Pb Free Device

NCP362应用:

USB Devices

Mobile Phones

Peripheral

Personal Digital Assistant

MP3/MP4 Players

TV and Set Top Boxes



图1.NCP362A典型应用电路(墙上适配器/VBUS TVS保护)



图2.NCP362C典型应用电路(USB用全集成ESD)



图3.演示板电路图

材料清单(BOM):