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Fast Charge EOS Solution OVP and TVS
EOS stands for Electrical Over Stress, which refers to situations where a device is subjected to excessive voltage and/or current signals it cannot handle, leading to damage. This phenomenon can occur through three main pathways: high voltage, high current, or a combination of both. While ESD (Electrostatic Discharge) events represent only one type of transient high-voltage EOS situation, addressing EOS requires considering both current levels and duration.
In today's world, mobile devices face increasingly complex charging environments, including car chargers, solar chargers, wall chargers, and fast chargers. Fragile smartphones must endure these varied charging methods, often resulting in malfunctions caused by overvoltage and overcurrent in the charging circuits. Regions like India and Africa, where power grids are less stable, experience higher incidences of EOS incidents. Mobile solution providers have responded by offering robust EOS protection solutions, catering to the demands of major brands such as Huawei and OPPO.
The need for reliable EOS testing has grown significantly. Although domestic standards currently lack specific over-voltage test indicators, international markets have seen increasing customer demands, with some requiring tests at up to 500V, reflecting heightened expectations for product durability. Protecting against overvoltage is conceptually straightforward but challenging in mobile devices due to space constraints. Engineers must design compact yet effective chips to meet these requirements.
One effective solution combines several advanced components. For instance, the PSMFJ24CA is a high-power TVS (Transient Voltage Suppressor) chip packaged in SOD-123FL, capable of handling up to 5000W. It can pass rigorous tests withstanding currents of up to 250A while maintaining a clamping voltage of 30V. Depending on terminal specifications, primary protection options include models with thresholds of 7V and 12V.
Another component is the OVP3881, an adjustable overvoltage protection chip that can be customized based on the threshold voltage of the main chip. Its flexibility ensures compatibility across different device designs.
The backend protection relies on the SD4501P4-3, another high-power TVS chip, packaged in DFN2020. Due to its low-voltage design, it can handle large currents effectively. Below are some test results for this TVS:
[Image description: Test data showing performance metrics of the SD4501P4-3 TVS chip]
As mobile technology evolves, ensuring robust EOS protection remains crucial. These solutions demonstrate how innovative engineering can address real-world challenges in modern electronics, providing users with dependable and resilient devices.