As the most widely used communication interface between mobile peripherals and the host, USB has the characteristics of low cost, simple use, support for plug and play, and easy expansion. It has been widely used in in-vehicle entertainment and storage devices.Because the USB interface provides a built-in power supply, it can provide a current of more than 500mA. For some devices with higher power, such as mobile hard disks, the instantaneous driving current can reach more than 1A.If the on-board ECU has an interface such as a USB bus that can directly output power, in order to prevent damage to the body when the interface circuit is short-circuited to the power supply or to the ground, the interface part usually has a protection circuit to perform fault self-diagnosis and protection functions.When the system fails, it can automatically record the fault code in the memory bank and take protective measures to prevent system damage and avoid safety accidents. The following is our solution for car USB port.

Circuit protection solution design for Automotive electronic USB port:

Application Background

1, USB2.0, USB3.0 need hot-swappable

2, USB2.0 transmission rate of up to 480Mbps, do not allow data loss packets; USB3.0 transmission rate is more high ththan USB2.0, here are stricter requirements for the fault tolerance rate of data transmission

3. The USB chip has high integration and is easily damaged by static electricity

Socay Solution and components for USB2.0

TVS diode 

【ESD05V14T-LC】Vrwm：5.0V；Vb：6.0V；Vesd：8KV/25KV；Ct（f=1MHz）：1.2pF；Package: SOT-143

The Solution Note

1. Use a TVS on the USB2.0 power line to protect the ground and clamp the electrostatic voltage

2、The junction capacitance of the TVS diode applied in the program is less than 1.2pF, which can complete the transmission signal at the maximum rate of 480Mbps in USB2.0

3. The TVS package used in the solution is SOT-143, which is small in size, saves PCB space, and is convenient for engineers to design

Socay Solution and components for USB3.0

TVS diode 

Part Number【SE03D3D01GW】Vrwm：5.0V；Vb：6.0V；Vesd：8KV/15V；Ct（f=1MHz）：0.8pF；Package: DSON-10

The Solution Note

1. Use two TVS diode on the USB3.0 power line to protect the ground and clamp the electrostatic voltage

2、The junction capacitance of the TVS diode applied in the program is less than 0.8pF, which meet the high-speed transmission of USB3.0

3. The TVS package used in the solution is SOT-143, which is small in size, saves PCB space, and is convenient for engineers to design

4.The response time is ns level, and low residual voltage

5.High integration

Application 

1. Laptop, PAD, home desktop computer, industrial computer

2. Network printer

3. Set-top box

4. Mobile handheld devices

5. TV

6. Vehicle

7. Other devices with USB2.0 ports

8. DVD recorder

For more information on USB interface protection solutions, please go directly to Socay's website to consult online customer service http://www.socay.com/