A few weeks ago, Realme unveiled its 240W fast charging tech with the Realme GT Neo 5 smartphone in China. The brand is set to unveil the tech globally at MWC 2023 under the Realme GT 3 branding. 

Redmi, subsidiary company owned by the Chinese electronics company, Xiaomi took to Weibo to announce their 300W fast charging technology. The brand calls their 300W charging as fairy second charging technology. Redmi is set to become the world’s fastest charging technology with the 300W charger. A video has also shared by brand on Weibo displaying the charger’s capability. The footage reveals the charging speed of 300W when paired with Redmi Note 12 Pro+.

Redmi’s 300W Super-Fast Charging Tech

The new 300W charger gets many technological upgrades and uses the fourth-generation GaN integration solution. The solution offers high power in a small size, low heat generation, and higher efficiency. The planar transformer inside the charger adopts an integrated modular design to compress the device’s space.

Xiaomi has managed to keep the size of the 300W GaN charger as its previous 210W charger. It is the reason why Xiaomi calls the product a second charging technology. The brand adopts a full-link self-developed 300-watt fast-charging architecture. It uses a customized 6:2 charge pump chip on the charging architecture, with a maximum conversion efficiency of 98%.

It also adds a large area of ​​graphene to assist heat dissipation based on glue filling and heat soaking. The charger has a uniform heat dissipation to achieve ultra-high-power output. Xiaomi revealed that the volume is the same as Xiaomi’s previous generation 210-watt charger with a 43% increase in power. The volume and its power density reach 2.31W / cm³.

Compared to the conventional 4:2 charge pump solution, the 6:2 pump solves the problem of high current heating in the charging input path. The pump also reduces the rising of the charging temperature from the source. The charge pumps adopt a decentralized layout to effectively avoid concentrated heat generation and prolong the duration of high-power charging.

The 300W Supercharger is based on a dual-string battery design and has the input current of the battery cell as 30A. The battery cell requires an ultra-high charging rate of 15C. To comply with this, Xiaomi has introduced a new type of hard carbon material in smartphone batteries. The rigid carbon structure is looser and more disordered than graphite, providing a better reaction path for lithium ions.

Compared with conventional electrodes, the new technology and process optimization measures reduce the thickness of the positive and negative electrodes by 35%. The charger adopts a sandwich structure stacking a different scheme from conventional double-cell side-by-side to achieve more substantial heat dissipation and higher space utilization. The battery PCM protection board also has a double-layer design to reduce the space occupation of the protection board by 50%.

The video on Weibo reveals that it only takes 5 minutes to charge the 4100mAh battery of the Redmi Note 12 Pro+. The smartphone can be charged up to 10% in 43 seconds, 50% in 2 minutes and 13 seconds and 100% in 5 minutes. The data given by Xiaomi officials reveals that it has a peak power of 290W, and power above 280W lasts for 2 minutes to charge the smartphone up to 50%. Xiaomi is yet to reveal the commercial availability of the product.