Xiaomi Detailed How In-House Surge P1 Chip Achieved 120W Single-Cell Fast-Charging

Today, Xiaomi announced its third self-developed chip Surge P1. Lei Jun said that the Mi 12 Pro will debut this chip. Also, it will be the first to realize a “120W single-cell” charging technology.

After the official statement, Xiaomi also explained the architecture and key parameters of the Surge P1 chip.

Xiaomi said that in the past single-cell fast-charging system, to convert the 20V voltage input to the mobile phone into a 5V voltage that can be charged into the battery, a series-parallel circuit of 5 different charge pumps is required. Moreover, a large number of charge pumps and an overall series-connected architecture will generate a lot of heat. In actual use, it is impossible to achieve full-power operation for a long time. It is hard to achieve a 120W high-power fast charging.

To solve this problem and reach a 120W fast charging, Xiaomi has developed two smart charging chips and put them into the Surge P1. These two take over the complex structure of the traditional 5 charge pump. They convert the high-voltage power input to the mobile phone into a large current that can be directly charged to the battery more efficiently.

Surge P1 Advantages

Xiaomi said that as the industry’s first resonant charging chip, the Surge P1 has a 4:1 ultra-high efficiency architecture with adaptive switching frequency. The efficiency of the resonant topology is as high as 97.5%; the efficiency of the non-resonant topology is 96.8%; the heat loss has plummeted by 30%.

The Surge P1 itself undertakes a lot of conversion work. Traditional charge pumps only need two working modes (transformation, pass-through). But the Surge P1 needs to support 1:1, 2:1, and 4:1 conversion modes. All modes need to support bidirectional conduction. This means that it needs a total of 15 permutations and combinations of mode switching control. This is 7 times that of traditional charge pumps. The forward 1:1 mode makes the bright screen charging more efficient; the forward 2:1 mode is compatible with more chargers; and the forward 4:1 can support 120W charging; the reverse 1:2/1:4 mode is available.

According to Xiaomi, the Surge P1 is also Xiaomi’s highest charging efficiency 4:1 charging chip. It can achieve an ultra-high power density of 0.83W / mm². Also, LDMOS has reached the industry’s leading ultra-low 1.18mΩmm² RSP.

The Surge P1 chip needs three different FLY capacitors with different voltage resistance. Each capacitor needs an independent open and short circuit protection circuit. Also, each operating mode needs to strictly control the pre-charge voltage. The number of power tubes is close to two of the traditional charge pumps. Because of the increase in topology design and functional complexity, each Surge P1 chip needs to pass more than 2500 tests before leaving the factory. This is much higher than the traditional charge pump.

Xiaomi Mi 12 Pro Charging

The Xiaomi Mi 12 Pro, which will be released on December 28, is the first smartphone equipped with the Surge P1. It supports wired 120W charging, 50W wireless charging, and 10W wireless reverse charging. Xiaomi said that the 120W charging technology of the Xiaomi Mi 12 Pro has two modes: low-temperature mode, “the temperature is only 37 degrees Celsius, and the body temperature is comfortable”; the fast mode.