With the explosion of TWS earphones, Xiaomi has also begun to lay out the market very early, and with its huge mobile phone user market, it has quickly stabilized the market. Its products adhere to a cost-effective route, with a very affordable price and excellent performance experience, and are deeply loved by mi fans and many other brand users.
Recently, Xiaomi has released its first flagship noise reduction earphones, the Xiaomi FlipBuds Pro, which uses 11mm ultra-dynamic speakers and is the world’s first to be equipped with Qualcomm’s QCC5151 flagship chip. It supports three-speed noise reduction mode and dual transparent mode, with a maximum noise reduction depth of 40dB; Support dual device connection, wireless charging, etc.
In terms of appearance design, the whole machine adopts high-gloss nano-NCVM coating process, which has a streamlined light feeling like a mirror surface. The back of the handle-shaped in-ear earphone is processed with a beveled surface through different processes to enhance the sense of hierarchy and texture of the product. A lot of research, testing and modification have also been done on the wearing, and the fit detection function is supported, so as to achieve a more comfortable wearing and the best audio experience.
52audio previously teardown Xiaomi Air 2 Pro, Xiaomi Air 2 SE, Xiaomi Air 2S, Xiaomi Air 2, Redmi AirDots 3, Redmi AirDots 2, Redmi AirDots, and 16 bluetooth earphones from Xiaomi speaker products, let’s take a look at the internal structure configuration of this product!
| 1. Xiaomi FlipBuds Pro Charging case teardown
After opening the box, it can be found that the appearance design of the Xiaomi FlipBuds Pro true wireless noise reduction headphones is very different from the previous generations of products. The high-gloss nano-NCVM coating process makes the whole machine feel very good. Next, we will enter the disassembly section to see the internal structure configuration of this product~
Heat to pry open the charging case cockpit.
The internal circuit of the cavity is composed of a main board and a FPC, and the two are connected by a flat cable and a BTB connector.
The main board is fixed to the bottom of the cavity by a number of screws, and a protective sticker is set on the main board to isolate it from the cockpit to prevent abrasion; the wireless charging coil is fixed on the back cavity wall of the charging case.
The main board circuit in the charging case.
bluetooth pairing button keycap.
Charging case Light guide on the inner side of the front indicator.
The front of the main board and the wireless charging coil.
The back of the motherboard and the wireless charging coil.
The back structure of the wireless charging coil, the white plastic plate is used for fixing, and the shielding sticker is set below to reduce electromagnetic interference.
The front of the wireless charging receiver coil.
Wireless charging receiving coil, multiple enameled wires are wound in parallel.
The BTB connector connected to the FPC on the main board is glued and reinforced.
The back of the motherboard is also affixed with black graphite heat dissipation stickers, the wireless charging coil wire is welded to the back of the motherboard, and the solder joints are glued to strengthen.
The circuit on the front of the motherboard.
Type-C charging socket on the motherboard.
A close-up of the function buttons on the motherboard, used for bluetooth pairing and connection.
TI TPS61023 synchronous boost converter, used to boost the built-in battery to charge the earphones.
WillSemi ESD5641 TVS protection diode, used for input overvoltage protection.
WillSemi ESD5641 detailed information.
The regulator IC of silk screen MJC.
WillSemi WS3222D over-voltage protection (OVP) load switch, used for Type-C interface input over-voltage protection. With adjustable OVLO threshold voltage, when any input voltage exceeds the threshold, the device will turn off the internal MOSFET, disconnect the input to the output, in order to protect the load.
WillSemi WS3222D details.
Two MOS tubes with silk-screened L1 are used for wireless and wired charging and power distribution switching.
NuVolta NU1680 is a small-sized, highly integrated wireless power receiver that integrates a synchronous rectifier, no bootstrap capacitor, and features high efficiency and low cost. It can provide a wide range of voltage regulation from 3.5V to 9V, suitable for different applications. And can adjust the output voltage to track the battery voltage, reducing the power consumption of the charging system.
NuVolta NU1680 can communicate with the transmitting system through ASK, and the communication conforms to WPC V1.2.4; FOD parameters can be configured through I2C interface or external resistance; NU1680 also supports I2C interface for communication; provides external interrupt, battery voltage ADC value, output current, etc. ; NU1680 also supports standard protection functions, such as over-current protection, short-circuit protection, over-voltage protection and thermal shutdown.
NuVolta NU1680 detailed information.
TI BQ21120 charging IC for charging the built-in battery in the charging case.
HDSC HC32L170 MCU is an MCU with ultra-low power consumption and wide voltage working range designed to extend the battery life of portable measurement systems, and is used for the control of the entire charging case.
Using Cortex-M0+ core, integrated 12-bit 1Msps high-precision SARADC, 1 12-bit DAC and integrated comparator, operational amplifier, built-in high-performance PWM timer, LCD display, multiple UART, SPI, I2C and other rich communications It has built-in information security modules such as AES and TRNG, which have the characteristics of high integration, high anti-interference, high reliability and ultra-low power consumption.
The charging case front structure of the cockpit is fixed with FPC soft board.
Charging case The rear structure of the cockpit is equipped with a fixed battery unit.
Rechargeable lithium-ion battery pack model: 801444PF4, rated capacity: 570mAh/2.19Wh, charging limit voltage: 4.4V, nominal voltage: 3.85V, manufacturer: Chongqing VDL Electronics Co., Ltd.
The two-dimensional code is printed on the back of the battery.
Tear off the label, and the internal silkscreen information is consistent with the external label.
Battery protection board, glue protection, with temperature detection, used for battery overcharge, overdischarge and overcurrent protection.
The LED indicator light is surrounded by black foam to prevent light leakage. The end of the cable is a Hall element.
The terminal of the FPC is connected to the small thimble board for charging the earphone with the charging case.
AWINIC AW9106B LED driver, used for indicator light drive.
The CellWise CW2015 fuel gauge chip can accurately estimate the remaining battery power and display the battery power in the pop-up window.
According to 52audio, a variety of earphones including Huawei FreeLace Pro noise reduction neck-mounted bluetooth earphones, Xiaomi true wireless bluetooth earphones Air 2s, Honor Flypods 3 true wireless active noise canceling earphones, Xiaomi true wireless bluetooth earphones Air 2 and other earphones all use CellWise fuel gauges. chip.
CellWise CW2015 details.
| 2. Xiaomi FlipBuds Pro earphones teardown
The overall appearance of the Xiaomi FlipBuds Pro earphones.
The back of the earphone handle adopts a bevel design and two different processing techniques, which enhance the sense of hierarchy and texture of the product.
The feed-forward noise-reduction microphone has an opening for picking up external environmental noise.
Silver metal contacts for charging the earphones.
The call microphone opening at the bottom of the earphone handle is used for voice call pickup.
There is a circular pressure relief hole on the front of the earphone, covered by a metal mesh.
There is also a small pressure relief hole in the sound tube.
The earphone has a special mouthpiece and is covered by a dust-proof net to prevent foreign objects from entering the sound cavity. There is a back-feed noise-reduction microphone for picking up the sound in the ear canal.
Open the earphone cavity along the earphone clamping line.
There is a flat cable between the front and rear cavities to connect through the BTB connector.
The components on the earphone handle cover are also connected to the main board in the cavity through a flat cable and a BTB connector.
Pick up all the BTB connectors to separate the cavity and the inside of the cavity.
Bluetooth antenna and two microphones in the cover of the earphone handle.
Take out the internal structure of the cover.
The plastic bracket in the cover adopts the same trapezoidal structure as the cavity, and the LDS laser antenna is printed on three sides, which increases the antenna area and improves the stability of connection and data transmission.
The MEMS silicon microphone of LaserDiao G034, the two microphones are of the same specification.
The inside of the earphone handle is a double-layer PCB board, which is connected by a flat cable. The side pressure sensing small board is connected to the upper PCB board through the BTB connector.
The main board at the bottom of the earphone handle is reinforced with glue, and the charging contacts are welded to the main board.
The upper PCB board is fixed on the lower PCB board through two soldering.
Use a soldering iron to remove the upper PCB board.
The structure in the back cavity of the earphone is fixed with a battery unit.
Take out the battery, there is an FPC cable connected to the motherboard underneath.
Magnet for earphone and charging case adsorption.
A layer of insulating transparent plastic is arranged inside the cavity for isolation between the main board and the battery.
The positive and negative poles of the button battery and the flat wire are welded on the side of the battery.
Solder the flat cable and remove the battery.
Steel shell button battery model 1154H, rated capacity: 54mAh/0.207W, rated voltage: 3.85V, also from VDL.
Remove the magnet structure, inside the cavity.
The magnet used for adsorption to the charging case is fixed on the wall of the earphone cavity by glue.
Remove the transparent plastic pad and you can see the motherboard. There is a bluetooth chip on the motherboard that is protected by a sponge pad.
Disconnect the solder joints between the motherboard and the charging thimble.
The pressure sensitive small board on the cavity wall is also connected to the main board through the BTB connector.
The back of the pressure sensor.
The front of the pressure sensor.
Xiaomi FlipBuds Pro true wireless noise reduction earphones motherboard circuit and RMB coin size comparison.
The circuit on the front of the motherboard.
The circuit on the back of the motherboard.
On the front of the upper PCB board, two BTBs are connected with microphones and pressure sensors.
The back of the upper PCB board.
The circuit on the front of the motherboard.
The circuit on the back of the motherboard.
A Hall element with silk-screened KR on the FPC cable.
Silkscreen AAA IC.
Silk screen BPPP AAE4 IC.
ST MEMS bone conduction voice switch LIS2DW12. In addition to supporting tapping, it also supports VAD’s voice switch, which uses vibration to determine whether the keyword is spoken by the person, reducing false triggers caused by other people’s keywords in the environment.
According to 52audio, the flagship TWS earphones of brands including Apple, Amazon, Samsung, Xiaomi, and vivo all use ST sensors.
The regulator IC of silk screen MJC.
Silkscreen D7DD 0TF1 IC.
GOODiX GH610 capacitive in-ear detection and touch 2 in 1 chip for in-ear detection and touch operation functions. It integrates a high-performance, low-power MCU and self-capacitance sensing front-end circuit, which can perform in-ear detection and touch operations according to capacitance changes, thereby realizing the control of the corresponding human-computer interaction interface system. This series of chips uses the sensing algorithm independently developed by Goodix Technology, which can achieve ultra-high signal-to-noise ratio, and can accurately identify the state of the earphones (worn/take off) and operations such as sliding, single double tap, and long press.
According to 52audio, there are already many TWS earphones from brands such as JBL, OnePlus, OPPO, realme, vivo, Baidu, 1MORE, etc., that have adopted GOODiX’s in-ear detection and touch 2-in-1 solution.
GOODiX GH610/611 system block diagram.
The memory of the silk screen Z7CLW 2049 stores bluetooth configuration and other information.
Willsemi WPMD2084 dual PMOS tube, used for input protection and backflow prevention function.
Willsemi WPMD2084 details.
TI BQ25618 charging IC, which integrates charging, boost converter and voltage protection functions, is used to charge the built-in lithium-ion battery of the earphones.
TI BQ25618 detailed information.
The ADI 71251 audio codec can improve the effect of active noise reduction while ensuring high-quality sound quality. It is reported that ADI’s new generation of ANC codec ADAU1860/ADAU1850 has already provided samples to the market and will be mass-produced in July this year.
The main control chip is covered with protective cotton.
Qualcomm QCC5151 bluetooth master SoC is an ultra-low-power single-chip solution. It adopts WLCSP package and has a smaller size. It supports bluetooth 5.2, has a programmable DSP, and is optimized for true wireless earphones and hearing devices.
Support Qualcomm adaptive active noise reduction (ANC), Qualcomm aptX adaptive audio, Qualcomm TrueWireless mirroring technology and Qualcomm eighth-generation cVc echo cancellation and noise suppression. Support voice assistant wake-up, including wake-up word wake-up and function key-press wake-up.
According to 52audio, there are already many TWS true wireless earphones, head-mounted, neck-mounted bluetooth earphones, smart speakers, smart audio glasses and other audio products that use Qualcomm bluetooth audio SoC.
Metal shrapnel connected to the bluetooth antenna.
A transparent frame is arranged on the wall of the front cavity of the earphone to isolate the ear detection unit to improve accuracy.
Take out the transparent frame and the internal structure of the cavity.
Capacitive ear detection units are arranged on both sides of the front cavity.
On the back of the speaker unit, the silk-screen information GTK 1218 A1A.
Take out the speaker unit.
The super dynamic speaker, according to the official introduction, uses a high-resilient diaphragm on the front, and the diaphragm is designed as a centering piece to make the voice coil vibration balanced and powerful.
According to the actual measurement of Woai Audio Network, the size of the speaker unit is about 11mm, which is consistent with the official publicity.
The internal structure of the earphone pressure relief hole.
The back-feed noise reduction microphone is located in the output tube under the speaker.
Laser carving G091’s MEMS silicon microphone.
All components of Xiaomi FlipBuds Pro noise-canceling headphones.
| 3. Summary
Xiaomi FlipBuds Pro true wireless noise-cancelling headphones have changed the design of previous generations of products in appearance and adopted a brand-new solution. The charging case has a rounded square shape and is treated with a high-gloss nano-NCVM coating process to achieve a streamlined light feeling like a mirror. And careful thinking about the charging case cover, the inclined charging case cover design is very stable when the cover is closed, it will automatically bounce to the open state when it is opened with a little force, and there is a sense of damping when it is closed, preventing the cover from being closed automatically.
The handle-shaped in-ear headphones are carefully designed on the back of the headphone handle. The trapezoidal structure and two different processing techniques enhance the sense of hierarchy and texture of the product. And the benefits of using this design are not only reflected in the appearance, the internal structure uses the same trapezoidal plastic bracket as the cavity, and the LDS is printed on three sides, which increases the antenna area and improves the stability of the connection and data transmission.
The internal structure is relatively complicated. The charging case circuit is divided into a main PCBA board and a FPC board. The two are connected through a BTB connector to improve assembly efficiency. The wireless charging coil is welded to the main board through a wire, and both are provided with shielding stickers to reduce electromagnetic interference. The wireless charging receiver chip is Volta NU1680 small size, highly integrated wireless power receiver, providing a wide range of voltage regulation from 3.5V to 9V, and also supports over-current, short-circuit, over-voltage protection and thermal shutdown.
charging case Built-in battery capacity of 570mAh, Type-C interface input power, equipped with TI BQ21120 charging IC to charge the battery, input overvoltage protection provided by Willsemi ESD5641 TVS protection diode and WS3222D overvoltage protection (OVP) load switch, TI TPS61023 synchronous boost The converter is used to boost the built-in battery to charge the earphone; Huada HC32L170 MCU with ultra-low power consumption and wide voltage working range is used for the whole machine control of the charging case. The FPC board is equipped with a status indicator, AWINIC AW9106B LED driver, and CellWise CW2015 fuel gauge chip, which is used to estimate the remaining battery power and display the power in the pop-up window; the end of the FPC is set as a small board for charging the earphones.
The internal circuit of the earphone, the loudspeaker unit in the front cavity, the capacitive in-ear detection, and the rear-feed noise reduction microphone are connected to a cable, which is connected to the extension cable of the motherboard through the BTB connector. The cable circuit is also welded with a steel shell button battery Power for the motherboard, with a capacity of 54mAh, from VDL.
Two PCB boards are arranged in the earphone handle, which are connected by a flat cable. The upper PCB acts as a transfer board and is provided with two BTB connectors to connect the microphone and pressure sensor in the trapezoidal cover of the earphone handle. The main control bluetooth chip on the motherboard uses Qualcomm’s latest QCC5151 flagship SoC, supports bluetooth 5.2, supports adaptive active noise reduction, Qualcomm aptX adaptive audio, Qualcomm TrueWireless mirroring technology and Qualcomm’s eighth-generation cVc call noise reduction technology; a plug-in The independent ADI71251 audio codec enhances the effect of active noise reduction while ensuring high-quality sound quality.
In other aspects of Xiaomi FlipBuds Pro, TI BQ25618 charging IC is used to charge the built-in lithium-ion battery of the earphone; Willsemi WPMD2084 dual PMOS tube is used for input protection and backflow prevention function; GOODiX GH610 capacitive in-ear detection and touch 2 1 chip, used for ear detection and touch operation operation function.
Check the Xiaomi FlipBuds Pro price:
Supported by Snapdragon Sound™ technology, Xiaomi FlipBuds Pro brings a consistent high-quality wireless audio experience
Qualcomm QCC5151 flagship bluetooth audio SoC adopted by Xiaomi FlipBuds Pro
Xiaomi FlipBuds Pro TWS earphones released, the first Qualcomm QCC5151 flagship chip, supporting dual low latency