Xiaomi Redmi Buds 4 Lite is a true wireless earphones launched by Redmi at the “2023 New Year Conference”. Compared with Redmi Buds 4 Pro and Redmi Buds 4, the handle-shaped semi-in-ear design is adopted in appearance, which is small and light, more comfortable to wear, and also improves portability.
In terms of function and configuration, Redmi Buds 4 Lite is equipped with a 12mm double-layer composite diaphragm dynamic driver, upgraded Bluetooth 5.3 technology, and has stronger anti-interference, more stable connection and lower latency. Support call noise reduction, built-in high-sensitivity microphone, with call noise reduction algorithm, provide clear call effect. In terms of battery life, the earbuds can last up to 5 hours at a time, and the combined battery life with the charging case can reach 20 hours.
We have also previously teardown Xiaomi’s products including: Xiaomi Buds 3 Pro, Xiaomi Buds 3, Xiaomi FlipBuds Pro, Xiaomi Air 2 Pro, Xiaomi Redmi Buds 4 Pro, Xiaomi Redmi Buds 4, Redmi AirDots 3 Pro, Xiaomi Watch S1, Redmi Watch 3 and Xiaomi Mi Band 7, etc.
01/ Redmi Buds 4 Lite charging case teardown
Disassemble the charging case shell and take out the charging cockpit structure.
The bottom structure of the charging cockpit, the main board is fixed by hot-melting plastic columns, and the battery is fixed on the main board by double-sided adhesive.
Remove the motherboard and battery unit.
The bottom structure of the charging cockpit is equipped with two magnets for absorbing earbuds.
The circuit on the side of the motherboard of the charging case.
The circuit on the other side of the charging case motherboard.
SinhMicro SS880MH is a low-power microcontroller with integrated power management function. The core of SS880X is an 8-bit MCU compatible with 8051 instruction set, with a maximum frequency of 12MHz. It integrates the power management unit and the charging management unit, supports battery or 5V adapter power supply, and supports charging batteries of different specifications and capacities. Combined with built-in low voltage, overvoltage, overcurrent, overtemperature and other detection and protection mechanisms, it can provide efficient and safe power solutions. The VIN pin has a withstand voltage treatment, the maximum withstand voltage of the low-voltage version is 14V, and the maximum withstand voltage of the high-voltage version is 28V.
SinhMicro SS880X series has a built-in linear charging management unit, which can charge single-cell lithium batteries, lithium iron phosphate batteries, etc. At the same time, it supports five modes: normal, low speed, idle, standby and hibernation. Support power-on, external pin, watchdog timer, VDD low voltage, debugger and software exception 6 reset methods.
As far as we know, SinhMicro POWER MCU has been used in Edifier, Black Shark, Xiaomi, OPPO, Honor, Redmi, realme, Nubia, Lenovo, Nokia, HTC, Soundcore, 1More, FIIL, 233621, JBL, Philips, Skullcandy , Razer and other brands have been widely used in more than 40 earphones.
The Hall element of silk screen AK2r7 is used to sense the magnetic field change (Hall effect) when the charging case cover is opened/closed. Notify the charging case MCU and earbuds to connect/disconnect with the paired device.
XySemi XB5152I2SZR integrated lithium battery protection IC. The XB5152 ZR series products are highly integrated solutions for Li-ion/polymer battery protection. Contains advanced power MOSFET, high precision voltage detection circuit and delay circuit. Housed in an ultra-small SOT23-5 package with only two peripheral devices, it is an ideal solution for limited space in battery packs.
As far as we know, Xiaomi, Redmi, MONSTER, Motorola, Anker, QCY, SoundPEATS, VANKYO, SONG, Honor, Edifier and many other TWS earbuds have adopted the XySemi lithium battery protection solution.
SinhMicro S61-C Boost IC is a high-efficiency synchronous boost converter with ultra-low quiescent current, and the efficiency can be as high as 94%. The SS61-C is capable of delivering at least 2W of power from a low voltage source, i.e. 0.4A at 5V output. It also has a true shutdown function, which disconnects the input and output under shutdown and output short-circuit conditions, without external MOS tubes, and provides strong output overload protection.
Cooperate with the boost IC to boost the built-in battery to charge the boost inductor for earbuds.
Pogo Pin connector for charging earbuds.
LED indicator light, surrounded by foam pads for shading.
Silkscreen 23P TVS tube for input overvoltage protection.
The information on the label of the built-in lithium battery of the charging case, model: BW33, nominal voltage: 3.65V, charging limit voltage: 4.2V, capacity: 320mAh 1.168Wh, manufacturer: LIWINON.
The silkscreen information on the battery cell is consistent with the external label.
Tear off the external high-temperature insulating tape, and weld the positive and negative nickel sheets of the battery with the wires by butt welding, and the battery protection is located on the main board.
02/ Redmi Buds 4 Lite earbuds teardown
Enter the earbuds teardown section and separate the cavity along the parting line earbud head.
Disconnect the wire and take out the battery. The earbud uses a soft button battery inside.
The inner structure of the pressure relief hole is equipped with a metal mesh protection to prevent foreign matter from entering the sound cavity.
The information on the label of the built-in lithium battery of the earphone, model: 1045N1, voltage: 3.8V, capacity: 35mAh 0.14Wh.
The silk screen information on the label on the other side, charging limit voltage: 4.35V, from LIWINON.
Tear off the label, and print a QR code on the cell for product traceability.
The product size is 10*4.5mm printed on the other side.
Take out the speaker, the internal structure of the front cavity.
The front of the speaker is covered with a metal cover for protection.
On the back of the speaker, there are three tuning holes on the edge, which are covered by a dust-proof net.
After actual measurement, the size of the speaker is about 12mm.
Remove the back cover of the headset stem, the internal structure of the cavity, and the main board is fixed by red glue.
The inside of the cover is provided with conductive cloth for touch control.
Take out the motherboard unit, the bottom structure of the headset stem cavity.
The Pogo Pin connector and magnet for earbud charging are fixed on the case.
The circuit on one side of the headphone motherboard.
The circuit on the other side of the headphone motherboard.
Laser carving R2AL 0LDK’s MEMS microphone is used for voice call pickup. The edge is a printed bluetooth antenna.
The 26.0MHz crystal oscillator provides the clock for the bluetooth chip.
Metal dome connected to conductive mesh for touch control function.
HYNITRON HK31BP high-performance self-capacitance touch chip for touch control function. HK31BP has a built-in voltage regulator module/low voltage reset module, supports hardware dejitter/environment adaptive algorithm, etc., has strong anti-interference performance, and can be configured into multiple modes through pins. the
Silkscreen 21 hx’s integrated lithium battery protection IC is responsible for battery overcharge, overdischarge, overcurrent and other protection functions.
BES BES2600IHC3 bluetooth Audio SoC. BES2600IHC series adopts dual-core Arm MCU, supports Bluetooth 5.3, integrates BES self-developed AI noise reduction call algorithm, hybrid ANC noise reduction algorithm and production line ANC self-calibration algorithm, integrates Charge, and consumes as little as 4.5mA. Low cost, cost-effective products.
As far as we know, there are currently many true wireless earphones under OPPO, Xiaomi, Samsung, vivo, Honor, IQOO, JBL, 1MORE, OnePlus and many other brands that have adopted BES Hengxuan’s solution.
All components of the Redmi Buds 4 Lite true wireless earphones.
In terms of appearance design, the charging case of Redmi Buds 4 Lite is small and light. The earbuds are made of smooth glossy material, the body is curved to fit the auricle, and the weight is only 4.0g, which can still guarantee a comfortable experience when worn for a long time.
In terms of internal structure and configuration, the charging case uses a Type-C interface for input power and a built-in 320mAh lithium battery. The motherboard is equipped with XySemi XB5152I2SZR integrated lithium battery protection IC responsible for battery charging protection. The SinhMicro SS880MH low-power microcontroller is responsible for charging the built-in battery and power management, and the SinhMicro SS61-C synchronous boost converter boosts the built-in battery to charge the earbuds.
The earbud uses a 12mm dynamic driver and a 35mAh button lithium battery. The main control chip adopts BES BES2600IHC3 bluetooth audio SoC, supports Bluetooth 5.3 and AI noise reduction call algorithm, and integrates Charge function. It also adopts HYNITRON HK31BP high-performance self-capacitance touch chip for touch control function. And a MEMS microphone for voice call pickup.