Redmi recently launched the Redmi Buds 3 true wireless earphones, the first product of the new TWS headset series. The design breaks through the original bean-shaped appearance and adopts a handle-shaped semi-in-ear type. The overall volume is small and the weight of a single earphone is only 4.5g. It also uses a high-gloss surface material, the body is smooth and round, and a straight line design is added to make the whole machine look more three-dimensional.
In terms of configuration, the Redmi Buds 3 true wireless headset uses a 12mm composite diaphragm large-size dynamic, Qualcomm QCC3040 bluetooth audio SoC, supports bluetooth 5.2, aptX™ Adaptive HD decoding, and cVc call noise reduction technology. Equipped with an infrared optical sensor to support in-ear detection function. It also supports a complete MIUI interconnection ecology, with pop-up window connection and remaining battery check functions.
52audio also teardown the Xiaomi FlipBuds Pro, Xiaomi Air 2 Pro, Xiaomi Air2 SE, Xiaomi Air 2S, Xiaomi Air 2, Redmi AirDots 3 Pro, Redmi AirDots 3, Redmi AirDots 2, Redmi AirDots, Xiaomi Xiaoai speaker and other 16 products of Xiaomi. Let’s take a look at the internal structure of this product.
|1. Redmi Buds 3 Charging case teardown
After reading the unpacking, we have a very detailed understanding of the appearance design of this product. Let’s disassemble it directly to see the internal structure design and configuration information.
Pry open the charging cockpit, which uses an upper and lower two-layer structure.
There are no components in the upper structure, and magnets are fixed to absorb the earphones and the charging case cover.
The internal structure of the cavity.
The main board, Hall element small board, battery unit and other important components are fixed on the lower structure.
Take out the lower structure in the cavity.
Inside structure of charging case shell.
The main board unit is fixed on one side of the charging case cockpit, and other components are connected to the main board by wire welding.
The battery is fixed in the groove on the other side of the cockpit.
At the bottom of the cockpit is a small pogo pin board for charging the headset.
The main components in the charging case are disassembled.
The Hall element small board, the Hall element senses the magnetic field change (Hall effect) when the charging case cover is opened/closed, notifies the charging case MCU, and then informs the headset to connect/disconnect with the paired device to realize the function of opening and closing the cover.
The charging case is a small board for charging the headset.
Pogo pin connector for charging the earphones.
The charging case built-in lithium-ion soft pack battery model: HT651729, rated voltage: 3.7V, rated capacity: 310mAh/1.15Wh, from EVERPOWER TECHNOLOGY.
According to 52audio, there are already true wireless headset charging cases of Bull, Jabra, Zepp Health Corporation and other brands that use EVERPOWER TECHNOLOGY soft pack batteries. Cleer TREK active noise reduction in-ear wired headphones also use a small square battery from EVERPOWER TECHNOLOGY.
The wire is welded to the nickel plate of the battery, and the lithium battery protection is set on the main board.
The circuit on the side of the main board is charging case.
Circuit on the other side of the motherboard.
MCU MCU with silk screen T32.
The jog function buttons on the motherboard.
ETAsolutions ETA9897 power management IC, ESOP8 package, is a bluetooth charging case two-in-one solution designed for low power consumption and high performance, which integrates charging and discharging. Support external MCU control, support EN enable, integrate 30V ultimate withstand voltage, 1uA standby power consumption when 5V no-load, and battery reverse connection protection.
According to 52audio, audio products of well-known brands including Edifier, 1MORE, Xiaomi, ZMI, realme, Baidu, Motorola, JVC, Klipsch, Panasonic, JBL and other well-known brands have adopted a large number of ETAsolutions power management chips.
XySemi XB5335A lithium battery charging protection IC, used for battery overcharge and overdischarge protection.
The TVS with silk screen T12 003, above is the input resettable fuse.
Type-C charging interface female socket.
|2. Redmi Buds 3 earphones teardown
Open the earphone head cavity along the parting line, and the inner components of the earphone head.
Special-shaped magnets on the cavity wall.
The connection between the FPC cable and the motherboard in the headphone head is protected by a large amount of glue.
The FPC cable is connected to the motherboard with a BTB connector.
Male BTB connector on FPC cable.
The other end of the FPC cable is an infrared in-ear detection sensor.
Infrared optical sensor black lens structure.
Infrared optical sensor, used for in-ear detection function, to achieve precise automatic suspension of removal, and automatic playback function when worn.
The earphone uses a button-type soft pack battery, model HT1040V, which is a 3.8V/4.35V high-voltage battery with a capacity of 35mAh/0.13Wh, from EVERPOWER TECHNOLOGY.
On the back of the battery, the positive and negative poles of the battery and the connection points of the wires are protected by insulating tape and sponge pads.
The speaker is directly welded to the FPC cable.
Screen printing 1QA4 battery protection IC.
On the front of the speaker, the diaphragm is covered with a layer of wool fiber to enhance the mid-bass effect.
After actual measurement, the size of the dynamic driver is about 12mm, which is consistent with the official publicity.
The inside of the pressure relief hole in the back cavity of the earphone is covered by a fine dust-proof net.
Inside the tuning hole of the front cavity of the earphone.
A plastic frame is arranged on one side of the motherboard inside the earphone handle, and a touch sensor and a bluetooth antenna are attached to the frame.
The circuit on the other side of the headset motherboard.
Headphone power input board, silver copper pillar.
In the middle is a MEMS microphone with a laser engraving QR code, which is used for voice call pickup.
Connect the female socket of the BTB connector of the FPC cable in the headphone head on the motherboard.
The touch chip of the silk screen HH01F is used to detect touch operations.
The IC of silk screen MK6.
The crystal oscillator of the laser carving UE provides the clock for the bluetooth chip.
The MEMS noise reduction microphone of LaserDiao QR code is used for voice call noise reduction function.
Qualcomm QCC3040 BGA package ultra-low power bluetooth audio SoC. QCC304x supports bluetooth V5.2 and aptX™ Adaptive audio coding, which integrates enhanced features such as stability, good sound quality, scalability, low latency and low bit rate audio transmission.
The QCC304x chip also supports the new Qualcomm TrueWireless™ Mirroring technology, and the left and right earbuds can be quickly switched in multiple usage scenarios. Support cVc call noise reduction technology, support touch or button to wake up the phone’s voice assistant; it can also integrate hybrid active noise reduction technology.
According to 52audio, well-known brands such as Anker, Bose, Beyerdynamic, B&O, Cleer, Edifier, Klipsch, Libratone, Xiaomi, Microsoft, OPPO, vivo, Sony, and 1More have adopted a large number of Qualcomm bluetooth audio SoCs.
All components of Redmi Buds 3 true wireless earphones.
Redmi Buds 3 true wireless headset charging case is designed to be lightweight and portable, with high-gloss surface material, more resistant to dirt and easy to clean. The handle-shaped semi-in-ear headphones have the same body texture as the charging case. The headphone handle adopts an integrated design, and the back also adds a straight line design, which makes the whole machine look more refined and three-dimensional.
In terms of internal circuits, the design of the charging case is relatively scattered, with a motherboard, battery, pogo pin board and Hall element board, and multiple components. The motherboard uses Type-C interface to input power, and the built-in 310mAh soft pack battery is charged by ETAsolutions ETA9897 power management IC, and the headset is discharged to charge. The Xysemi XB5335A lithium battery charging protection IC is responsible for the overcharge and overdischarge protection of the built-in battery.
In the Redmi Buds 3 earphones part, the 12mm speaker in the earphone cavity, the EVERPOWER TECHNOLOGY 35mAh high-voltage soft-pack button battery, and the optical in-ear detection sensor are all connected to an FPC cable, and then connected to the motherboard through the BTB connector. On the motherboard, the main control chip is a Qualcomm QCC3040 BGA packaged ultra-low power bluetooth audio SoC, which supports bluetooth V5.2, aptX HD decoding, cVc call noise reduction, etc. Built-in two MEMS microphones, with noise reduction algorithm, used to achieve clear voice call function.