The appearance of Bose QuietComFort Earbuds uses a new bean design, which adds a new purple version. Inherited the classic sound quality of Bose and supports 5 sections of EQ adjustment. Inherited the iconic noise elimination technology of BOSE, effectively isolated from external interference, and provided immersive music experience. Support three modes: ANC OFF, ANC ON, and transparent to meet the use of multiple scenarios. A single battery life is up to 8.5 hours, and the comprehensive music playback time is up to 29 hours. Plus, the charging case supports wireless charging.
We have previously teardown the Bose products including: Bose QuietComfort Ultra Earbuds, Bose QuietComfort Earbuds II, Bose Sport Earbuds, Bose Soundsport Free, Bose QuietComFort Ultra Headphones, Bose QuietComFort 45, Bose NC700 and Bose Soundlink Home. Let’s take a look at the detailed teardown report of Bose QuietComfort Earbuds.
01/ Bose QuietComfort Earbuds Charging Case Teardown
Disassemble the charging case and take out the charging bin structure. The charging bin is connected to the metal connector for charging the earbuds through a wire. The motherboard unit is fixed by screws inside the cavity, and the wires are welded to the motherboard.
Remove the screws and take out the motherboard – the battery and wireless charging receiving coil are set at the bottom of the charging bin.
Take out the battery and wireless charging receiving coil.
Tear off the battery insulation protection, and the parameter information is printed on the battery cell. Model: VDL 522827PN3, rated capacity: 450mAh 1.71Wh, nominal voltage: 3.8V, from VDL.
The battery protection board circuit is equipped with a lithium battery protection IC and MOS tube, as well as a thermistor for detecting battery temperature – responsible for overcharge, over-discharge, and overcurrent protection of the battery.
The circuit on one side of the charging case motherboard.
The circuit on the other side of the charging case motherboard.
ConvenientPower CPS4019 wireless charging receiving chip, supporting 5W wireless charging reception. The chip integrates synchronous rectifiers and low-dropout regulators for charging system devices and batteries.
CPS4019 integrates an 8051 core, built-in 16KB MTP memory and 2KB SRAM. Supporting advanced power management and ultra-low standby power consumption, the chip has I²C pins and GPIO pins. Supporting output voltage adjustment, built-in 12-bit ADC for input and output full parameter acquisition. The chip has built-in rectifier overvoltage protection, LDO overcurrent protection and overheating protection, and adopts WLCSP-30 package.
8.0000MHz crystal oscillator is used to provide clock. ConvenientPower CPS5201 power management chip integrates an overvoltage protection circuit, a Switch Charger and a Boost circuit. Its input withstand voltage is 30V, and the switch charger can support a maximum charging current of 1.1A. Boost can support 5V/0.5A output.
ConvenientPower CPS5201 has ultra-low standby current, supports portable devices, and is very suitable for TWS charging case and other 1-unit lithium battery applications. CPS5201 fully integrated protection, including bus overvoltage, overtemperature, overcurrent protection and temperature control regulation loop. Plus, it also has an LED indicator function.
Nations N32L406CBL7 MCU. The N32L40X series uses a 32-bit ARM Cortex-M4 core with a maximum operating frequency of 64MHz. It supports floating-point operations and DSP instructions, and integrates up to 128KB embedded encrypted Flash and 24KB SRAM. It integrates a rich set of high-performance analog devices, built-in 1 12bit 5Msps ADC, 2 independent rail-to-rail operational amplifiers, 2 high-speed comparators, and 1 1Msps 12bit DAC. It supports up to 24 channels of capacitive touch buttons and integrates up to 320 segments of Segment LCD drivers; it integrates multiple U(S)ART, I2C, SPI, USB, and CAN digital communication interfaces, and a built-in cryptographic algorithm hardware acceleration engine.
IC with silkscreen 2T1 and IC with H5D.
TI TLV9002S operational amplifier. The TI TLV900x series has rail-to-rail input and output swing capabilities. These operational amplifiers provide a cost-effective solution for space-constrained products that require low operating voltage and high capacitive load drivers. The capacitive load driver of this series has a capacitance of 500pF, and the resistive open-loop output impedance makes it easier to achieve stability with higher capacitive loads.
02/ Bose QuietComfort Earbuds Teardown
Disassemble the earbud head, and the motherboard unit is set at the bottom of the back cavity.
Remove the battery, and the front cavity is isolated by a cover.
The earbuds have a built-in soft-pack button battery, model: VDL 1254PF4F, rated capacity: 70mAh, nominal voltage: 3.85V, from VDL.
Remove the front cavity cover, and weld the speaker wire to the FPC.
Take out the speaker and the motherboard inside the back cavity.
The end of the FPC at the bottom of the front cavity is connected to the wearing detection sensor and the backfeed microphone.
The circuit on one side of the earbud motherboard.
The circuit on the other side of the earbud motherboard.
The 26.000MHz crystal oscillator that provides the clock for the bluetooth chip (below). AIROHA AB1585 bluetooth audio SoC (above), supports LE Audio and Bluetooth 5.3; integrates ARM Cortex-M33F application processor, HiFi 5 DSP, bluetooth transceiver and power management unit (PMU). Supports Hybrid Active Noise Cancellation (ANC), a new generation of echo cancellation and AI noise reduction solutions. Supports Airoha MCSync technology, allowing seamless switching between left and right earbuds for more balanced sound and low latency.
IC with silkscreen 4W AsP.
Pogo Pin connector for connecting Bluetooth antenna and touch detection patch.
Gyroscope IC with screen printing VP 215, used to collect head movement data.
BTB connector female socket connected to FPC. IC with screen printing AM Gm.
Take out the FPC and components inside the front cavity.
Bluetooth antenna and touch detection patch are set at the bottom of the back cavity.
FPC circuit inside the earbud.
FPC connects to the BTB connector of the motherboard.
The front of the earbud speaker is protected by a metal cover.
The back of the speaker is equipped with a tuning hole on the side, which is protected by a screen.
After actual measurement, the diameter of the speaker is about 10mm.
The MEMS microphone of the laser carving GY24 is a feed-back noise reduction microphone, which is used to pick up noise from the inside of the ear canal to further improve the noise reduction effect.
The optical wearing detection sensor is used to automatically pause the playback when the earbud is taken off, and automatically resume the playback function after wearing.
The MEMS microphone of the laser carving FR24 is a call microphone, which is used to pick up sound for voice call function.
Another laser-engraved FR24 MEMS microphone is a feed-forward noise reduction call microphone used to pick up external environmental noise.
All components of Bose QuietComfort Noise Cancelling Earbuds.
03/ Summary
Bose QuietComfort Earbuds use a new design – compared to Bose QuietComfort Ultra, the overall size is more compact and portable. The bean-shaped in-ear earbuds, with silicone eartips and stability bands of various sizes, can better adapt to the wearing needs of different users.
The charging case is equipped with a 450mAh lithium battery and supports wired and wireless charging modes. The wired mode uses the ConvenientPower CPS5201 power management chip, and the wireless mode uses the ConvenientPower CPS4019 wireless charging receiver chip. It is also equipped with Nations N32L406CBL7 MCU, TI TLV9002S operational amplifier, etc.
The earbuds are equipped with a 70mAh soft-pack button battery and a 10mm dynamic driver. They have three built-in MEMS microphones for voice calls and noise reduction pickup. The main control chip is AIROHA AB1585 bluetooth audio SoC, which supports hybrid ANC, a new generation of echo cancellation and AI call noise reduction. A gyroscope is also preset, and the head tracking spatial audio function may be upgraded in the future.
PS: Translated from 52audio
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