USB2.0 ESD And Protection

USB2.0 ports

USB2.0 ports are often used to provide power and often charge peripherals and portable electronics.

According to the USB2.0 standard, a USB-compliant power supply should be between 4.75V and 5.25V and provide a continuous current of at least 0.5A.

However, some failures may still occur, easily damaging downstream electronic circuits without protection measures. Typical faults include: inductive spikes, connection to a high-voltage charger, and connection to a power source with contaminated power quality. Although the voltage of a typical calculator power supply is controlled at 5V +/- 5%, this does not mean that the voltage of the USB port will not exceed 5.25V. Induced voltage spikes can exceed 8V and damage unprotected peripherals. The spike phenomenon occurs when there is a certain inductance on the power bus and the current changes rapidly. The rapid changes in current may come from hot plugging of peripherals, shutdown of internal systems, or other internal power supply fluctuations. Inductance may be caused by the use of magnetic components in the design, or it may be caused by long cables and other power bus components. The larger the inductance value of the power bus, the more severe the spike voltage generated in the peripheral. In short, USB devices may be subject to voltages in excess of 5V and protection measures should be taken against this situation.

Advantage

• Helps protect downstream electronics from overvoltage and negative bias conditions

• Action event can cut off over voltage and reverse bias source

• The simulation characteristics of the operating state can minimize the upstream inductive spike voltage

• Single-part layout and low thermal requirements help reduce design costs

Features

Ⅱ．USB2.0 Controller ESD Protection Standard Solution

IEC 61000-4-2(Contact: 15 kV Air: 20 kV）