With the rapid development of TWS headsets, the market has gradually shifted from the explosive development stage to more brand-specific products. In the layout of this year’s TWS headset, Xiaomi changed its product positioning plan in previous years and launched two products in a row. Xiaomi FlipBuds Pro and Xiaomi true wireless noise reduction earphone 3 Pro are both focused on the mid-to-high-end market, and they are also very distinctive in product design.
Xiaomi Buds 3 Pro was released in September this year. The appearance of the headphones is inspired by the Mobius ring, and the streamlined decorative belt is designed with smooth and elegant curves, making it more personalized. In terms of functions, spatial audio is supported for the first time, and a 360° surround sound field is added to provide immersive audio effects. And through the built-in gyroscope to achieve dynamic head tracking.
In terms of hardware and software configuration, Xiaomi Buds 3 Pro uses a diamond-like dual magnetic unit, supports LHDC4.0 ultra-clear audio protocol, and can support up to 24bit/96kHz high-definition audio transmission. Support adaptive active noise reduction function, dual transparent mode, three-mic call noise reduction, the maximum noise reduction depth can reach 40dB. It uses pressure-sensitive buttons, supports Qi wireless charging, IP55 dust and water resistance, and has an overall battery life of 27 hours.
52audio has teardown the Xiaomi products: Xiaomi FlipBuds Pro, Xiaomi Air 2 Pro, Xiaomi Air 2 SE, Xiaomi Air 2S, Xiaomi Air 2, Redmi AirDots 3 Pro, Redmi AirDots 3, Redmi AirDots 2, Redmi AirDots, Xiaomi xiaoai speaker Play, Xiaomi xiaoai portable speaker and other 16 products of Xiaomi. Let’s take a look at the internal structure of this product.
|1. Xiaomi Buds 3 Pro Charging case teardown
After unpacking, we learned in detail about the unique design of the Mi True Wireless Noise Cancelling Headphones 3 Pro True Wireless Headphones. Let’s enter the disassembly part to see the internal structure and configuration.
Pry open the charging case shell, the internal structure consists of two parts, the bottom of the cockpit is fixed with a small charging board, which is connected to the main board through a cable.
Take out the internal components of the charging case.
In the bottom structure of the cockpit, the metal contacts for charging the earphones are connected to an FPC cable.
The charging contacts are fixed by a large amount of white glue.
Magnet used to adsorb the charging case cover.
Magnet used to attract headphones.
There is an FPC cable on the front of the bracket that fixes the main circuit in the charging case, and there are indicator lights, Hall elements, etc. on it.
The bottom of the bracket is the motherboard unit, which is fixed by screws. Below the motherboard is the battery unit.
charging case Wireless charging receiving coil.
Two FPC wiring circuits in the charging case.
ZIF connector used to connect to the motherboard.
The charging case is the metal dome used to charge the headset.
The charging case indicator on the cable, and the outer black sponge wrap to prevent light leakage.
The Hall element of the silk-screen AR1P1 is used to sense the change of the magnetic field when the charging case is opened and closed, and notify the charging case MCU and the headset to pair or disconnect with the connected device.
The lithium-ion soft pack battery in the charging case, model: BW50, rated capacity: 480mAh/1.82Wh, nominal voltage: 3.8V, charging limit voltage 4.35V.
The cell silk screen information under the label is consistent with the outside.
The positive and negative nickel sheets and wires of the battery are welded by resistance welding, and the protection IC is located on the main board.
The circuit on the side of the charging case motherboard, the left and right wires are connected to the battery and the wireless charging receiving coil, and the solder joints are glued to reinforce the protection.
On the other side of the motherboard, the main ICs are reinforced with glue.
The Type-C charging interface female seat is protected by a rubber pad.
TPS SY8801 TWS headset charging compartment SOC, specially designed for TWS headset charging compartment, based on the design to ensure safe and high reliability (support 28V input withstand voltage, built-in full-featured charging and discharging overvoltage, overcurrent, overtemperature, and short circuit Protection and other functions), I2C communication function and internal communication isolation function are also integrated. Through the I2C interface, the system’s MCU can read and configure the internal functions of the power supply and the parameters of battery charging and discharging management, and easily realize such as NTC protection, segmented adjustment of battery current, TWS earphone in warehouse, warehouse out detection, and automatic power output. And other functions.
The integrated internal communication isolation module of TPS SY8801 greatly optimizes the functional design of the intelligent TWS charging compartment, without complicated peripheral circuits, and the MCU can be realized by connecting and controlling the SY8801. Not only can it realize the function of charging the earphones, but also the data communication transmission can be carried out through the power source POGO PIN connected with the earphones, including functions such as uploading the power of the charging bin, clearing the pairing of the earphones in the charging bin, restoring factory settings, and upgrading the earphone software.
According to 52audio, the TPS power management chip has been adopted by many well-known brands such as OPPO, Xiaomi, Baidu, 1MORE, 233621, Transsion, Sabbat, Creative, and OnePlus.
3R3 power inductor.
XySemi XB5152J2SZR Lithium battery protection IC with load reverse connection.
Connect the ZIF connector of the FPC cable.
Bluetooth pairing function button.
COPO CP2022 is a single-chip, advanced, flexible, secondary-side wireless charging and transmission chip, which can provide up to 3W of power for portable applications. It has the advantages of high integration, high efficiency, and low power consumption. It conforms to Qi V1.2.4 standard. On the outside of the chip are the resonant capacitors and filter capacitors used for wireless charging and receiving.
According to 52audio, the COPO wireless charging receiving solution has been widely adopted by OPPO, Edifier, Baseus, Sabbat, realme, omthing, iWALK, TOZO and other brands of TWS headsets.
The LPS LP5305 overvoltage and overcurrent protection IC is used for USB-C input overvoltage protection. It also supports front-end protection of the lithium battery charger. When the battery is overvoltage, the charger input is disconnected to provide a complete and comprehensive protection function.
According to 52audio, audio products from brands such as Xiaomi, OPPO, Huawei, Lenovo, Motorola, Realme, Edifier, QCY, JLab, Skullcandy, Boltune and other brands have adopted a large number of LPS power management solutions.
The TVS with M24A on the back of the Type-C interface is used for input overvoltage protection.
The IC of BEKEN BK2538W is used to control the charging case.
16.000MHz crystal oscillator provides clock for BEKEN chip.
|2. Xiaomi Buds 3 Pro earphones teardown
Enter the disassembly part of the earphone and pry open the shell along the mold line.
The components in the front cavity are equipped with isolation covers, and the internal components are connected to the main board through a flat cable.
The internal structure of the back cavity of the earphone is fixed with a lot of glue.
Remove the magnetic shielding sticker, you can see the FPC cable is welded to the back of the speaker, and the isolating plastic part is fixed with a lot of glue.
Remove the plastic parts, the internal structure of the cavity.
Pry open the speaker unit, the internal structure of the cavity.
A back-feed noise reduction microphone is arranged inside the sound hole cover to collect the internal noise of the ear canal.
An ear detection patch is also affixed to the cavity wall, and the L logo is silk-printed on it for easy identification during assembly.
FPC cable circuit inside the earphone.
The front of the diamond-like dual magnetic unit adopts DLC high-hardness diaphragm.
On the back of the speaker, there are tuning holes around to improve the acoustic performance.
After actual measurement, the speaker size is about 10mm.
Laser carving M1 17P91 MEMS microphone.
Take out the main board and battery unit in the rear cavity, the main board cable extends to the inside of the earphone handle, and there is a coaxial cable to connect the main board and the small board in the earphone handle.
The internal components of the back cavity are fixed on the bracket, and a large amount of glue is used to fix the main board on one side.
The other side is the battery unit, and the battery is protected by a rubber cushion.
Remove the motherboard from the bracket and take out the battery.
The bracket and magnet are fixed inside the earphone.
The headset uses a soft-pack button high-voltage battery, model: GF 1054P, rated voltage: 3.8V, rated capacity: 0.144Wh, from Ganfeng Lithium.
A large area of the circuit on the motherboard side is occupied by the main control chip.
On the other side of the motherboard, a BTB connector is connected to the components in the front cavity.
Pry off the decorative strap on the back of the earphone handle.
A bracket is also arranged under the cover, and a large-area LDS laser antenna is printed on the bracket.
Xiaomi 3 Pro true wireless noise cancelling earphones teardown.
The inner structure of the stent.
The internal structure of the cavity.
The microphone opening inside the cavity is protected by a dust-proof net.
The pressure sensor is fixed on the cavity wall and connected to the main board through the BTB.
Pressure sensor side circuit.
The pressure sensor is fixed on the metal bracket.
The circuit on the side of the PCB board in the earphone handle. There are two MEMS microphones on the left and right sides, and a pressure sensor is connected to the middle BTB.
Circuit on the other side of the PCB.
Chipsea CSU18M68 pressure sensor detection IC is a SOC with dual-channel pressure sensing measurement function. It can be used in mobile phones, wearables, notebooks, industrial, home appliances and other fields. It supports AFE mode and MCU mode.
The gyroscope IC of the silk screen 718LD1.
Laser carving M1 17733’s MEMS noise reduction microphone is used for active noise reduction and call noise reduction to pick up external environmental noise.
Connect the metal dome of the bluetooth antenna.
The MEMS call microphone of LaserDiao M1 17733 is used for voice call pickup.
BES BES2500ZP bluetooth audio SoC, supports active noise reduction (including feedforward noise reduction, feedback noise reduction, hybrid noise reduction, adaptive noise reduction, AI voice noise reduction), and supports three microphones to achieve high-definition call noise reduction. The chip also has strong radio frequency performance, with an average power consumption of less than 5mA, which can realize long battery life or small size earphone design.
The full range of BES2500 supports bluetooth V5.2, the built-in MCU frequency is up to 300MHz, and supports LE Audio-LC3 technology, which can provide higher sound quality at the same rate.
According to 52audio, the BES2500 series has been used by brands such as Samsung, OPPO, Honor and other brands. BES bluetooth audio solutions have been developed by brands such as Samsung, Xiaomi, OPPO, JBL, 1MORE, Honor, Baidu, OnePlus, and Transsion. True wireless headsets are widely used.
The crystal oscillator that provides the clock for the bluetooth chip.
Silk screen UJD IC.
Silk screen AM CJ’s IC.
Xysemi XBL6015J2S-SM (silk screen 1TPx) with shipping mode, discharge overcurrent 0.15A lithium battery protection IC.
All components of Xiaomi 3 Pro true wireless noise cancelling earphones.
|3. Summary
Xiaomi Buds 3 Pro true wireless noise cancelling earphones are biased towards Xiaomi FlipBuds Pro in appearance, but the overall texture is very different. The charging case is made of frosted material, the light feel is more restrained and mysterious, without the mirror-like streamline light feel of the millet FlipBuds Pro high-gloss nano-NCVM coating process. The size of the earphone is lighter, and the Mobius ring decorative belt enhances the overall texture and recognition.
In terms of internal structure configuration, the charging case supports both wired and wireless input methods. The built-in battery capacity is 480mAh, and it is equipped with Xysemi XB5152J2SZR lithium battery protection IC. The cable uses the Type-C interface to input power, and the TPS SY8801 charging bin solution charges the built-in battery, and is responsible for the battery boost to charge the headset. It also integrates the I2C communication function and the internal communication isolation function.
The wireless charging is in charge of the COPO CP2022 wireless charging transmission chip, the maximum power can reach 3W, and it supports the Qi V1.2.4 standard. LPS LP5305 overvoltage and overcurrent protection IC and BEKEN BK2538W IC are used.
The front cavity and the back cavity of the earphone are equipped with isolation layers, and the components in the front cavity are connected in series on an FPC cable and connected to the main board through the BTB. The motherboard and battery in the rear cavity are fixed on plastic parts, using a 3.8V high-voltage soft-pack button battery with a capacity of 0.144Wh, from Ganfeng Lithium, and also equipped with Xysemi XBL6015J2S-SM lithium battery protection IC.
The Xiaomi Buds 3 Pro earbuds motherboard uses a combination of software and hardware board technology, the main control chip is BES BES2500ZP bluetooth audio SoC, bluetooth V5.2, supports active noise reduction, three-mic call noise reduction, supports LE Audio-LC3 technology, and can work at the same rate Provides higher sound quality. Built-in pressure sensor, with CHIPSEA CSU18M68 pressure sensor detection IC, to achieve the control of various functions. Three MEMS microphone units are used for active noise reduction and call noise reduction.
Source: 52audio
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