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Wayon helps you choose the optimal circuit protection products

Emerging industries, such as 5G, new energy vehicles and the Internet of Things, are connected to the ever-upgrading consumer market at one end and the rapidly developing scientific and technological innovation at the other. It is worth noting that the construction of all kinds of industries is closely related to the development of semiconductor technology. Whenever there is a new technological breakthrough in terminal equipment, matching semiconductor components will be needed. At the same time, manufacturers in all industries are pushing for improved product performance, trying to strike a balance between innovation and proven, reliable solutions. Taking electronic protection subsystems as an example, these systems protect sensitive and costly downstream electronic devices (ASICs, microprocessors, etc.). Due to their characteristics, designers are faced with the difficult task of balancing design complexity, reliability and cost.

Traditional protection solutions are often inefficient, bulky, and require maintenance. In order to address these shortcomings and help designers narrow down their options for more suitable solutions, this article shares some typical applications of protection components to show their features and the characteristics of suggested applications.


Typical Application Solution I
Mobile phone VCharge port EOS protection


 

Tested device: Mobile phone;
Test standard: IEC61000-4-5, 1.2/50-8/20us, 2Ω, EOS 350V, DC 24V;
Client-end situation: Using a single 12V TVS as port surge protection, the system boots up FAIL after surge testing;
Cause Analysis: Failure analysis results show that both the TVS and the post-stage IC have damage points. After a laboratory recurrence of failure, it can be observed that the plastic seal on the surface of the component melted and the internal chip showed a large area of burned points, determined that the failure was caused by prolonged overvoltage;
Solution: Replace with a 24V TVS as the port surge protection component and equipped with an OVP component WP3116, the surge test level can be increased up to 350V, while meeting the DC 24V voltage test;
The advantages after modification: replace with a 24V TVS component with a higher surge protection level, while the residual energy is absorbed by the post-stage OVP. When testing the DC voltage, TVS does not operate and the OVP performs overvoltage shutdown, thus providing better protection.



 

左图:单颗TVS方案 ;右图:TVS+OVP方案


Recommended TVS+OVP protection solution 
for mobile phone Vcharge/Vbat port is as follows:






 

Wayon recommended protection components


 

Typical Application Solution II
Security DC12V port surge protection

 

Tested device: Security IPC camera;
Test standard: IEC61000-4-5, 1.2/50-8/20us, 2Ω, surge 2KV;
Market situation: Increasing repair rate;
Cause Analysis: The failure analysis results of the returned products show that the protection components and post-stage DC-DC have different degrees of damage. It is caused by the fact that clients have upgraded the surge test standard from 1KV to 2KV and DC/DC has switched for products with weaker DC voltage.
Solution: Security products mostly use centralized power supply and have huge lightning induction energy, low-voltage components are more prone to breakdown. Therefore, the products require higher through-current capability. Replace with components with negative resistance process and SMB package.
The advantages after modification: Pushing wafer N-well deeper to obtain better clamping capability, and the SMB package carries larger wafers to greatly improve surge resistance and enhance the protection capability of the entire system.


 

1.2/50us-8/20us 2Ω 2KV


 

System operates without faults after surge


Surge protection solution for security IPC DC12V port is as follows:




 

Wayon recommended protection components

 

 

Typical Application Solution III
High-speed signal cable HDMI port ESD protection



 

Tested device: Security NVR;
Test standard: IEC61000-4-2 contact 8KV, air 15KV;
Market situation: Signal interruptions during the use of end products;
Cause Analysis: Failure analysis results show that TVS and back-end ICs have both breakdowns. Due to the high integration degree of IC system required for ultra HD transmission, the parameter specifications of conventional products are unable to meet the protection requirements of high-speed signal ports;
Solution: Replace with an SCR protection component as port protection. Anode connects to signal port and Cathode connects to GND; When Anode is impacted by ESD/EOS, the NW/PW junction is broken down, and the NPN and PNP are on at the same time, entering an amplification state, forming positive feedback, latch-up and snap-back occur, reducing the voltage clamp to a very low level, so as to effectively protect the latch-stage IC;
The advantages after modification: The SCR component has the advantages of ultra-low clamp voltage, strong through-current capacity, ultra-low capacitance, and strong ESD resistance, which can effectively improve the system performance. The array products can also significantly reduce the PCB footprint.




 

Protection component location


 

The entire device has been tested as normal


ESD protection solution for HDMI port is as follows:




 

SCR I-V curves


 

Wayon recommended protection components


Note: Wayon is one of the few Chinese manufacturers that can independently develop and design circuit protection components with SCR craft. The company has successfully developed single-way and multi-way components with SCR craft in various packages and achieved mass production, which enables Wayon to response to customers faster.

 

 

Typical Application Solution IV
Automotive load dump and headlight load dump 
protection


 

Tested device: Automotive day light project mainboard;
Test port: DC 24V power port;
Test level: ISO16750-2 P5a 24V system; US=202V; T=60S; Td=350ms; Ri=2Ω; 10 times; 
Client-end situation: Using SM8S36A 6600W PTVS as protection component, the inductor is placed before the protection component in order to solve the system EMI. By testing 5A load dump, the inductor smokes and TVS breaks down, and the system power supply is interrupted;
Cause Analysis: The failure analysis results show that the inductor is damaged and the PTVS broke down. It is caused by the fact that load dump current instantly broke down the inductor due to insufficient power of the inductor;
Solution: Replace the SM8S36A with a higher power SM8T36A, while placing the inductor after the protection component and adding a cooling plate. Passed the highest level of 16750 5A system load dump test.



 

Electrical testing on the bare mainboard


 

Electrical testing on the mainboard with cooling plate


 

 

Protection solution for diverse automotive ports is as follows:


 

 


Choose the right protection component for your application


As with all product selection, it is important to understand the system requirements before making the right decision. How can you find the best smart protection component?

1. Know what damage you want to prevent;
2. Decide what outcome you want in the event of failure;
3. Make reasonable assumptions about the "normal" and "abnormal" operating conditions;
4. Be aware that no protection is 100% safe;
5. The circuit protection solution should be planned at the beginning of the design.

Wayon selection manual already shows many possible applications. For more detailed product data, you can view the protection component parameter table within our website, select the operating voltage range when determining the size of the component, select the number of channels, and filter the function to narrow down the range of feasible options.


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