On September 10, Huawei released the FreeBuds Pro true wireless bluetooth earphones. This is Huawei’s first true wireless earphones named “Pro” and the world’s first true wireless earphones that supports smart dynamic noise reduction. The earphones works in different environments. Use will automatically switch different levels of noise reduction mode to ensure wearing comfort and a more natural user experience.
In order to achieve the best effect of active noise reduction, Huawei FreeBuds Pro adopts an in-ear design for the first time compared with its predecessors. The official advertised maximum noise reduction depth is 40dB. At the same time, in order to ensure the comfort of wearing, the earphone is designed with a pressure balance and transparent transmission system, and the sound cavity is maintained while the internal and external pressure is balanced; and the earphone also supports the transmission of ambient sound and enhanced human voice transmission, so there is no need to take it off when communicating with others earphones.
In other configurations, Huawei FreeBuds Pro uses a dual-antenna design to enhance signal transmission capabilities and improve connection stability; the earphones shell adds a dual anti-wind noise design, and the call noise reduction function uses three microphones and bone vibration sensors to achieve; In the interactive mode, the earphones has a built-in pressure sensor, which supports the operations of pinch to play/pause, pinch two/three times to change the song, long press to change the operation mode, and support sliding to adjust the volume.
Not only that, Huawei FreeBuds Pro is used with Huawei mobile phones equipped with EMUI 11 system, and it can also “unlock” multiple functions such as earphones search, high-definition recording, dynamic EQ adjustment, and the earphones’s battery life has also been greatly improved. It is more complete.
Huawei FreeBuds Pro has three colors of ceramic white, frosty silver, and carbon crystal black. It is divided into two versions: wireless charging and wired charging. The official said that the two are only the difference between supporting/not supporting wireless charging. Let’s take a look at 52audio versus wireless. Detailed dismantling of the full version!
52audio has teardown the Huawei FreeLace Pro, Huawei AI smart speaker 2, and Huawei FreeBuds 3 true wireless earphones.
01/ Huawei FreeBuds Pro charging case teardown
After unpacking the box, I believe that everyone has a preliminary impression of the appearance design of Huawei FreeBuds Pro wireless earphones. The charging case retains many elements on Huawei FreeBuds 3. Let’s enter the disassembly process and take a look at its wired charging power management system. What are the solutions adopted by the wireless charging power management system.
The back of the charging case is heated, and this decorative piece is removed.
The decorative piece is fixed by glue.
Metal shaft position.
Pry open the charging cockpit and fix it with buckle and glue.
There is a small PCBA on the side of the matching button position, and two metal contacts on the inside.
The front of the internal structure of the charging cockpit is shown as a wireless charging receiving coil.
The internal structure of the charging cockpit is displayed on the back, and you can see the wiring of the FPC.
The internal structure of the charging cockpit is shown on one side. The charging coil is curved to suit the shape of the housing.
The internal structure of the charging cockpit is displayed on the side of the pairing button.
The bottom surface of the internal structure of the charging cockpit is displayed. The internal components are all fixed on this plastic middle frame.
Remove the screws and remove the plastic fixing bracket at the bottom.
There is a PCBA at the bottom of the charging cockpit.
From top to bottom, there are the FPC connector on the back of the earphones, the charging port connector, and the battery connector.
Disconnect the connector and remove the PCBA at the bottom of the charging cockpit.
The battery is individually fixed with a plastic case.
The inside of the charging cockpit shell is displayed. There are four magnets on each of the left and right earphone cavity positions to absorb the earphones.
The FPC display in the earphone is connected to the Pogo Pin at the earphone sound cavity, the pairing button on the side of the earphone, the status indicator of the earphone and the Hall element.
The status indicator of the earphones and the Hall element with silk screen 789 017. The magnetic field changes when the charging case cover is opened and closed will be sensed by the Hall element, and the charging case MCU and earphones will be notified to pair or disconnect with the connected device.
Pogo Pin is covered with rubber to prevent dust and water.
The other side of the FPC inside the earphones is displayed.
Inside the charging cockpit shell, there is a magnet at the opening of the cover, a magnet at the earphone position, and a protective cover at the indicator light position to avoid light leakage.
The metal dome for charging the earphone is connected to the motherboard. Below is the screw hole for fixing the PCBA at the bottom of the charging box.
Remove the plastic protective cover of the battery module.
There is a cushion protection pad inside the plastic protective cover.
The soft pack battery is fixed in the plastic shell. Battery information, model: HB781937ECW, rated capacity: 580mAh, rated voltage: 3.82V, charging limit voltage: 4.4V.
Take out the battery and separate the components.
A close-up of the battery fixing module.
The supplier of the soft pack battery comes from ATL Technology Co., Ltd.
The battery protection board has lithium battery protection IC and PTC thermistor to provide battery over-voltage, over-discharge and over-current protection, and the battery protection chip is glued.
The relevant circuit at the charging interface at the bottom of the charging box.
The charging interface related circuit is shown on the other side.
The metal plate for fixing the charging port and the charging indicator.
The Type-C charging interface is displayed on the side.
The Type-C charging interface is shown on the other side.
The protective cover of the Type-C charging port is dustproof and waterproof.
The main circuit inside the charging case is displayed.
The other side of the main circuit inside the charging case is displayed.
Receiving coil for wireless charging. The transmitting coil of the wireless charger generates a certain current in the receiving coil based on a certain frequency of alternating current through the electromagnetic induction effect, thereby transferring electrical energy from the transmitting end to the receiving end, and then powering the battery in the TWS charging case.
A close-up of the wireless charging receiving coil, multiple strands of enameled wire wound together.
The charging case PCBA is shown on one side, the left side is the socket with three connectors, and the right side is the wireless charging receiving related circuit.
The charging case PCBA is displayed on the other side.
Resonant capacitor for wireless charging and receiving.
ST STWLC33 is a highly integrated high-performance wireless charging chip that also supports Qi wireless charging reception and reverse charging functions to meet the requirements of mobile phones and various low-power applications.
TI TPS63810 2.5A buck-boost converter, using I2C interface control, for battery voltage conversion.
Silkscreen HCKV AFD IC.
The IC of silk screen AGE.
ST STM32F411CE high-performance basic series ARM Cortex-M4 MCU with DSP and FPU, with 512 KB Flash, 100 MHz CPU and ART accelerator.
TI TPS63810 synchronous buck-boost converter.
TI BQ25601 battery charge management and system power path management IC.
Silkscreen A3Z IC.
Silkscreen P5 H5 IC.
AWINIC AW9106B LED driver for indicator light drive.
The regulator of silk screen ADH.
The IC of the silk screen 71J.
Silk screen N6S IC.
All components of Huawei FreeBuds Pro charging case.
02/ Huawei FreeBuds Pro earphones teardown
Let’s continue to disassemble the earphone part. This time Huawei FreeBuds Pro has upgraded the earphone part more, supporting active noise reduction, pressure-sensitive touch and sliding control; the internal structure also uses a three-microphone system and bone voice print call noise reduction Technology, there are dual anti-wind noise design, dual antenna design, etc. Let’s take a look at it through disassembly.
FreeBuds Pro is the first in-ear design for Huawei’s true wireless earphones, which has a certain passive noise reduction effect and is conducive to the design of active noise reduction. The earphone handle is more square, in contrast with the smooth curve of the sound cavity shell, and it is more comfortable to wear.
At the bottom of the earphone handle, there are bar-shaped charging contacts on both sides.
The Huawei brand name is on the outer cover of the earphone handle. This area does not support touch.
On the side of the earphone handle, you can see that there are two anti-wind noise duct designs on the top and bottom, which are also the pickup holes for the feedforward microphone and the call microphone.
The other side of the earphone handle is displayed and supports long-press, slide, and pinch controls.
The cutaway view of the earphone shell shows that the anti-wind noise ducts on both sides of the earphone handle are connected. The wind enters from one side. According to the Coanda effect, most of the gas will flow along the inner wall and exit from the other side; at the same time, between the microphone and the duct There is also a distance, with a dust net on the outside, which can further reduce wind noise. The picture is quoted from the digital blogger “Look at the evaluation first.”
The contact at the bottom of the earphones cavity.
There is a metal dust-proof net inside the pressure relief hole inside the sound cavity of the earphone, and next to it is the window of the infrared distance sensor for ear detection.
The fine dust-proof net at the sound hole contains a feedback microphone for active noise reduction.
Disassemble the earphones handle, the main board circuit is inside the shell.
Inside the earphone handle, the two parts of the circuit are connected through a connector.
Disassemble the sound cavity shell along the parting line.
Sheet iron used to absorb the charging cockpit.
Earphones shell display.
The other side of the earphone housing is shown.
The opening of the contact position.
FPC that connects internal components such as speaker units and batteries.
On the other side of the FPC, it is connected to the motherboard through a connector.
The solder joints of button batteries.
The solder joints of the speaker unit.
Open the solder joints of the battery and take out the battery. The positive pole in the middle of the battery and the negative pole on the outer shell.
Remove the button battery.
The speaker unit is individually sealed with a large amount of white glue.
The label information on the side of the battery, HUAWEI, ICR12/07, HB1160ECW.
The battery capacity is 55mAh, the rated voltage is 3.82V, and the charging limit voltage is 4.4V.
Number information of the button battery.
There is a plastic bracket inside the sound cavity.
Take out the plastic bracket.
Close-up of transparent plastic bracket.
The speaker unit and infrared distance sensor are fixed with a lot of white glue.
A close-up of the inside of the pressure relief hole, fixed with red glue.
Remove the sealant and take out the speaker unit.
The back-feed microphone is designed at the position of the sound hole to collect sound information mixed with noise and music in the ear canal and feed it back to the noise reduction chip.
Close-up of the speaker unit diaphragm.
The number information on the speaker unit T iron, H200916A 1511311.
The size of the moving coil unit is 11mm, consistent with the publicity.
Take out the other plastic bracket holding the speaker unit.
A close-up of the structural design of the back-feed microphone and the sound hole, and there are two solder joints on the metal bracket.
Take out the metal bracket holding the feed microphone.
The solder joints are connected to the dust screen.
Take out the infrared distance sensor, a close-up of the window inside the shell.
FPC display in the sound cavity, connected with button battery, speaker unit, infrared distance sensor and feed-back microphone.
Display on the other side of FPC.
Infrared distance sensor.
Capacitive sensing device used to assist in-ear detection.
The solder joints of the cable are reinforced with red glue.
Silkscreen MU6K2E IC.
The IC of the silk screen 71H.
Silkscreen 3566H 2021 IC.
Silk screen 3GP4 QAC2 0065 4048 IC.
The internal structure of the earphone handle is displayed, and the left and right earphones have the same layout.
Disconnect the FPC connector.
Take out the motherboard.
The earphones adopts the design of two motherboards, and the two motherboards are connected by a soft board.
The charging contacts on the bottom of the earphone handle.
Pressure sensor on the side of the earphone handle.
There is a dual antenna design on the earphone shell, which is connected to the motherboard through two metal contacts.
Take out the pressure sensor and connect it to the motherboard through the connector.
The pressure sensor sensing area is displayed, filled with foam, and the application diagram is shown below.
The external circuit of the earphones motherboard is displayed.
The internal circuit of the earphones motherboard is displayed, and the main control chip is individually packaged in a metal shield.
The feed-forward microphone on the top of the earphones handle is mainly used to pick up ambient sound, and is used together with the feed-back microphone for active noise reduction.
The call microphone at the bottom of the earphones handle is mainly used to pick up human voices during a call.
Officially marked as a component of the bone voiceprint sensor.
Connect the two metal dome of the bluetooth antenna, next to the microphone hole.
The IC of silk screen TZ.
Glue-encapsulated memory chip.
ADI ADAU1787 audio DSP chip, built-in 4ADC and dual DAC for active noise reduction.
According to 52audio, many products of brands such as Amazon, BOSE, and Xiaonia have adopted ADI’s TWS noise reduction solution.
ST LIS2DW12 acceleration sensor, supports tap induction, VAD voice switch and bone conduction call noise reduction.
According to 52audio, the flagship TWS earphones of brands including Apple, Amazon, Samsung, Xiaomi, vivo, and Go Ask all use ST sensors.
Silkscreen 356H 2027 IC.
Silk-screen AAG IC.
The IC of the silk screen LC.
The CHIPSEA CSA37F61 force sensor has built-in 8 differential input channels, 1 ForceTouchAFE, supports I2C/UART communication, and can reconstruct the ForceTouch algorithm. CSA37F61 supports various forms of border touch interaction of mobile phones/earphones and other products, such as sliding, gestures, and squeezing.
The memory of the silk screen Q64FWY.
There is a metal cover outside the main control chip with a piece of metalized cotton on it, and the corresponding area of the other motherboard has a heat dissipation design.
The bluetooth SoC of Silkscreen Hi 1132, Hisilicon Kirin A1 chip, bluetooth 5.1 and bluetooth low energy dual certification, adopts dual-channel synchronous transmission technology, is equipped with a high-rate audio processing unit, and supports stable and fast wireless connections. It was previously applied to Huawei FreeBuds 3 wireless earphones and other Huawei smart wearable devices.
All components of Huawei FreeBuds Pro.
Huawei FreeBuds Pro true wireless earphones are the first to adopt a handle-in-ear design, which can achieve better active noise reduction effects; the earphone shell adopts a bright surface design, which is in contrast to the matte texture of the charging box; due to the change in earphone size, charging case The volume has increased correspondingly, but many design elements of the previous Huawei FreeBuds 3 are retained, including the wireless charging coil on the front of the charging case, the position of the pairing button, the design of the metal hinge, and the position of the earphones indicator and charging indicator.
In the Huawei FreeBuds Pro charging case, there is a plastic middle frame to fix each internal structure, and the soft pack battery is also fixed by a plastic shell separately; there are 10 magnets on the inside of the charging cockpit to absorb the earphone and the cover separately, increasing the earphone placement and the cover Stability; the charging interface of the charging box is fixed with a metal plate. The structural design of the charging box is better, and the volume and weight of the charging box are correspondingly increased.
In terms of internal circuits, Huawei’s FreeBuds Pro wireless charging version, the wireless charging receiver IC is ST STWLC33, and TI TPS63810 performs buck-boost conversion; the wired charging system uses Type-C interface input power, and TI BQ25601 is responsible for battery charging management. TI TPS63810 The synchronous buck-boost converter is responsible for battery charging and discharging; wired charging/wireless charging supports fast charging; the soft pack battery used in the charging case comes from ATL; the internal circuit of the charging case also has AWINIC AW9106B for indicator driving, ST STM32F411CE The MCU is responsible for the overall control of the charging case.
The structural design of the Huawei FreeBuds Pro earphones is also quite distinctive. The earphones handle is a square design with dual motherboards connected through a soft board. The main control chip is protected by a metal cover and has a heat dissipation design. There are two wind resistance on the outermost cover. Noise duct design uses fluid mechanics to reduce wind noise; at the same time, the outer shell of the earphone also uses a dual antenna design to increase the signal coverage area and improve connection stability; the speaker unit inside the earphone is sealed separately and fixed with a plastic bracket; inside the sound cavity A FPC is connected with button battery, speaker unit, infrared distance sensor and feed-back microphone; there are many components and the structure design is complicated.
The bluetooth master chip of Huawei FreeBuds Pro is Kirin A1, and the active noise reduction DSP is ADI ADAU1787. In addition to the feed-forward microphone and the feed-back microphone, there is also a call microphone and a bone voice sensor in the earphones that work together for call noise reduction; The earphones’s long-press, slide, and pinch control methods are from CHIPSEA CSA37F61, and are implemented through related sensor design; the earphones uses multiple ICs to complete the earphones’s various functions.