Xiaomi Surge P1 Powering Xiaomi 12 Pro’s 120W Single-cell

Xiaomi Surge P1 Charging Chip Introduction

Xiaomi Surge P1 Charging Chip Introduction

Besides the built-in dynamic performance scheduling technology, today, Xiaomi also announced Xiaomi Surge P1 – the third Xiaomi self-research chip.

According to the introduction, Xiaomi Surge P1 is a self-research charging chip, there will be Xiaomi 12 Pro first equipped, it is with the Surge P1, the industry’s first 120W single-cell charging technology.

Officially, the Surge P1 after 18 months, the four major R&D centers to cooperate, spending more than 100 million, and finally achieve a large power 120W fast charging under the thin and light body while also supporting 50W wireless charging and 10W wireless reverse charging.

Xiaomi released two self-research chips this year, respectively, Surge C1 and Surge P1, the former is an ISP chip, has been installed in Xiaomi MIX FOLD, and Surge P1 is a charging chip, will be used in Xiaomi 12 Pro.

As we all know, the current hundred-watt fast charging is composed of double cells, while Xiaomi 12 Pro after the built-in Surge P1, to achieve 120W single cell, according to the battery energy, single-cell is higher than double cells, the same volume to maintain greater battery capacity.

Xiaomi Surge P1 Official Introduction

From 2019 when Xiaomi released the first generation of fast charging models to Xiaomi MIX4’s 120W fast second charging system, the wired fast charging speed has doubled 7.4 times, and the wireless fast charging speed has doubled 12 times.

Now, with the included charger, it only takes 15 minutes to be fully charged. This has made many users completely change the habit of charging all night long, to charging as they go, using fragments of time to quickly recharge. In a real sense, it has achieved a qualitative change in the charging experience.

To achieve such a goal, Xiaomi set fast charging as an important strategic direction in 2019, set up four major R&D centers, and established the TMG charging technology committee. Within three years, it has equipped hundreds of millions of devices with fast charging systems and applied for more than 800 patents.

At the beginning of the next decade, we need to think about whether fast charging systems should continue to pursue speed or should we choose a new direction?

120W single-cell solution, the biggest convention of fast charging, range, and thinness

Fast charging is a systemic project, involving life, safety, range, and other dimensions. If one pursues the limit of charging time, it will cause compromise in other aspects.

Currently, smartphones with 120W wired charging speed invariably use a dual-cell system. The cost of high speed is reduced space utilization inside the phone: the space that could have been reserved for the cell is taken up by more complex charging circuitry and dual-cell structure, and the capacity of a dual-string cell is about 4% lower for the same volume.

In addition, a 2:1 chip is needed to step down the voltage when discharging the dual-string battery, and its conversion efficiency results in a 3% to 4% waste of power. The single-cell charging system can circumvent these problems, but increasing the charging power to more than 100W is a huge challenge.

This is the goal of the Xiaomi Surge second charging system: to achieve the best balance of range and charging performance, to achieve a single-cell 120W wired second charging.

Surge P1, fill the 120W single-cell fast charging industry gap

In the past single-cell fast-charging system, to convert the 20V voltage input to the phone into 5V voltage that can be charged to the battery, a series-parallel circuit of 5 different charge pumps is required. A large number of charge pumps and the overall series architecture will bring a lot of heat, and in practice, it is completely impossible to run at full power for a long time, and even more difficult to achieve 120W high power fast charging, which is unacceptable for Xiaomi.

To redesign the entire charging architecture, the function of the fast-charging chip needs to be redefined. The core of Xiaomi’s 120W Surge the second charge is two Xiaomi self-developed smart charging chips: the Surge P1, which take over the complex structure of the traditional 5-charge pump, converting the high-voltage electrical energy input to the phone into a high current that can charge the battery directly more efficiently.

As the industry’s first resonant charging chip, the P1 has a 4:1 ultra-high efficiency architecture with an adaptive switching frequency, resonant topology efficiency of 97.5%, and non-resonant topology efficiency of 96.8%, with a 30% drop in the thermal loss.

The Surge P1 itself takes on a lot of conversion work: while traditional charge pumps require only two operating modes (variable voltage, straight-through), the Surge P1 needs to support 1:1, 2:1, and 4:1 conversion modes, and all modes need to support dual-wire, which means a total of 15 permutations of mode switching control – 7 times more than conventional charge pumps. The forward 1:1 mode allows for more efficient bright screen charging, the forward 2:1 mode is compatible with more chargers, the forward 4:1 supports 120W surging second charging, and the reverse 1:2/1:4 mode supports high power reverse charging.

Charging efficiency is the highest, the most difficult to design 4:1 charging chip

At the same time, the Surge P1 is also the Xiaomi charging efficiency of the highest 4:1 charging chip, can achieve 0.83W/mm² ultra-high power density, LDMOS also reached the industry-leading ultra-low 1.18mΩmm² RSP and Surge P1 chip internal need to use three different voltage FLY capacitors, each capacitor requires independent open and short circuit protection circuit, and each mode of work requires strict control. The number of power tubes is near twice the number of traditional charge pumps. And because of the increased topology design and functional complexity, each Surge P1 needs to pass more than 2500 tests at the factory, much higher than traditional charge pumps.

Ultimately, with its help, we were able to significantly simplify the circuitry, while the ultra-high efficiency of the Surge P1 itself means that heat generation is in the ideal range to sustain full power operation for longer, and wireless charging is supported.

The upcoming Xiaomi 12 Pro is the first smartphone to feature the Surge P1, which supports wired 120W Surge second charging, 50W wireless second charging, and 10W wireless reverse charging. Thanks to the single-cell high-power design, it meets a full day of battery life.

On the road of fast charging, Xiaomi is already far ahead of other manufacturers, using its fast-charging chip to take the lead in implementing fast-charging technology on its products a year ahead. We have more good news to share with you at the launch event on December 28, so stay tuned.


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