HomePod is a series of smart speaker under Apple. The first Apple HomePod debuted at the Apple Developers Conference in 2017, focusing on sound quality and equipped with top-level hardware configuration. In October 2020, Apple HomePod Mini will be launched, with a small size and greatly enriched product functions. Recently, Apple HomePod series ushered in a new generation of product. This time, I will share with you the teardown of the new smart speaker.
Apple HomePod 2nd generation continues the design language of this series of products in terms of appearance, but the size is slightly smaller than the first generation. The body shell is covered by a seamless sound-transmitting mesh, and a backlit touchpad is designed on the top, making the overall look and feel very simple. In terms of configuration, it is equipped with 5 beamforming tweeters + 1 high-amplitude woofer, uses the Apple S7 chip, and introduces advanced computing audio technology to greatly optimize the acoustic performance.
In terms of functions, HomePod 2nd generation uses audio technology combined with advanced software to intelligently tune the sound according to the playback content and placement position, ensuring a full range of high-fidelity sound quality. Supporting the spatial audio function, the beam-forming tweeter will accurately focus the direct sound to the center of the room, and at the same time disperse the ambient sound to the wall and bounce back, thereby creating an immersive listening experience. It also supports air playback, audio streaming, combined stereo and other functions to enrich the audio experience.
The HomePod 2nd generation also brings the highly intelligent “Siri” smart assistant and supports the new Matter smart home connection standard. With various HomeKit accessories, it is convenient to control various smart homes through Siri. It can also be controlled remotely using the Home app. The HomePod 2nd generation has added a sound recognition function, which can monitor sounds such as smoke and carbon monoxide alarms in real time and notify users through mobile devices. It also supports humidity and temperature monitoring, creating automatic operations and other functions, which greatly enriches the user experience.
Apple HomePod 2nd generation teardown
Enter the teardown part and remove the outer cover of the base.
Bottom inner structure. The middle of the bottom plate is fixed on the flange with double-sided foam glue, and there are 10 rubber pillars visible on the periphery (the double-sided glue can be removed) for cushioning.
The inner structure of the cover plate that fixes the pressure plate is provided with a layer of sponge pad, which is used to absorb the vibration generated by the speaker and the contact surface when it is working.
The bottom structure of the speaker cavity. There are connection contacts for debugging in the middle, surrounded by grille sound holes of the tweeter.
Peel off the seamless sound-permeable mesh, the main structure of the speaker. A layer of finer elastic weaving net is also arranged on the inner side of the weaving net. From the outside, the speaker has a three-layer structure. The top layer is the motherboard where the touch components and Soc are located, the middle layer is the woofer, and the lower layer is the power amplifier board, power module and multiple sets of tweeters.
Temperature and humidity sensing sensor holes.
There are two pickup microphone holes on the fuselage.
The top of the fuselage is a sound hole grille, and there are fixing screws around it, which are filled with rubber plugs.
Remove the screws and disassemble the sound outlet grille structure.
The main board unit is arranged inside the grille, and the internal components of the cavity are connected by cables.
Open the connector to remove the sound hole grille, and the inner motherboard is fixed by screws.
The backlit touch panel on the top of the grid structure is fixed to the cavity by screws, and connected to the motherboard by a cable.
The structure of the touch panel adopts the same transparent electrode technology as the touch screen of the mobile phone.
The light guide structure of the RGB LED light group is fixed on one side of the motherboard.
The main components on the other side are shielded and protected by the metal cover, which also helps the components dissipate heat.
The RGB LED light group circuit on the motherboard, 37 RGB LED lights are distributed radially, which can present more delicate color changes.
One of the LDS antennas.
Another LDS antenna.
Printed WiFi/Bluetooth antenna.
Another printed WiFi/Bluetooth antenna.
RGB LED lights.
Light sensor.
Synaptics S3808B touch detection chip.
TI TLC5955 RGB LED driver x 3, is a 48-channel, constant sink current driver. Each channel has an independently adjustable, pulse width modulated (PWM), gray scale (GS) bright block control. This control has 65,536 steps and 128 steps of constant current point correction (DC). DC can adjust the brightness deviation between channels. All channels have a 128-step global brightness control (BC). BC adjusts the brightness deviation among R, G, B color groups. 8-step Maximum Current Control (MC) Selects the maximum output current range for all channels of each color group. GS, DC, BC and MC data can be accessed through a serial interface port.
The TLC5955 has two error flags, LED Open Detection (LOD) and LED Short Detection (LSD). Error detection results can be read using a serial interface port.
The bass equalizer microphone on the main board is sealed by hard glue and is used to monitor the sound of the bass unit and realize dynamic adjustment of the low frequency part.
The microphone pickup hole on the other side of the motherboard is protected by a dust filter.
Some circuit components.
Wireless module with silk screen QR code USI.
The WiFi+Bluetooth module with silk screen QR code USI 339M00243.
The internal circuit after removing the shield cover.
The main IC is coated with heat dissipation silicon grease to improve heat dissipation performance.
There is a circle of conductive cloth shielding on the connection position between the metal cover and the lower PCB board.
Silkscreen A1 IC.
TI TPS56637 is a high-efficiency, high-voltage input, easy-to-use synchronous buck converter with integrated MOSFETs. Due to the wide operating input voltage range from 4.5V to 28V. The TPS56637 is ideal for systems powered by 12V, 19V, and 24V bus rails. Its output voltage ranges from 0.6V to 13V and supports up to 6A of continuous output current.
Silkscreen DK4 LP IC.
Silkscreen OCTA1 IC.
Apple custom screen printing 338S00925 power management IC.
Apple S7 processor is manufactured using TSMC’s 7nm process, which greatly improves computing power and reduces power consumption. Supports advanced computational audio technology, runs complex tuning models in real time through feedback from new system-level sensors, preserves dynamic range as much as possible, and greatly optimizes acoustic performance.
Continue to teardown the middle frame part and take out the woofer. The woofer is very heavy, accounting for more than half of the entire speaker.
Three layers of cushioning material are set at the connection between the woofer and the cavity. From top to bottom: thick rubber, sponge, thin rubber.
The side structure of the woofer.
The T-iron on the back of the woofer has an airflow hole in the center.
The internal structure of the speaker cavity.
The cable through hole connecting the power input board and the main board is fixed and sealed with a rubber wire harness.
The metal cooling plate of the power amplifier IC is fixed by screws on the PCB, and it is also used to connect the cavity and fix it.
Remove the screws and remove the speaker bass unit cavity.
The bottom tweeter is fixed with two PCB boards by screws. The C-shaped one is the power amplifier circuit, and the inside is the power module.
The acoustic structure of the microphone on the cavity is covered with a dust-proof net and connected to the microphone pickup hole of the shell.
The connecting structure of the upper and lower chambers, the groove of the lower part of the chamber is filled with rubber pads for cushioning and vibration reduction. The microphone pickup hole on the edge of the power amplifier motherboard – corresponds to the hole on the middle frame.
The connector connecting the speaker power module and the power amplifier circuit board is fixed by screws.
Remove the screws, remove the AC-DC circuit board, and connect the lower wire to the power input interface.
AC-DC circuit board side circuit.
The circuit on the other side of the AC-DC circuit board.
Metal case shielded common mode inductors.
The rectifier bridge is fixed together with the EMI circuit using hard glue.
The components are filled with black hard glue for shock resistance.
Inductor, the MOV next to it is protected by a heat shrinkable tube.
Two Y capacitors are placed between the primary and secondary of the power supply.
The main switch tube of the power supply has an aluminum sheet to assist heat dissipation.
X3-FM T0-01B main transformer, tightly wound tape insulation.
Filter capacitors, sinking board welding, reduce the thickness of the PCB board.
The high-voltage filter capacitor comes from Rubycon, 400V 120μF, LXW series ultra-small size, 10,000-hour lifespan.
There is also a Y capacitor in the primary part of the power supply.
Silkscreen L44 1008-W optocoupler.
UTC MGBR10U300 secondary rectifier MOS tube adopts UTC’s advanced technology and has the advantages of low forward voltage drop and high switching speed.
The output filter uses three Rubycon solid-liquid hybrid capacitors. Two specifications are 56μF 63V and 33μF 63V, and one specification is 47μF 35V.
Screen printing R050 current-sensing chip resistors.
Silkscreen 358 IC.
Silkscreen 2P 16 IC.
Integral shielded inductance.
ON Semiconductor NCP1342 is used as the PWM main control chip. This is a high-frequency primary PWM controller with built-in active X2 capacitor discharge and multiple perfect protection functions.
The other two L44 1008-W optocouplers.
Diodes AP4310E is a monolithic IC designed for regulating output current and voltage levels of switching battery chargers and power supplies. The device contains two operational amplifiers and a 2.5V precision shunt voltage reference.
Two silkscreen RMLW diodes.
Silkscreen WZ9 26 and ZG23 ICs.
Silk screen AWW 28 IC.
Connect the connector contacts of the amplifier circuit board. The wide pins are for power and the narrow pins are for signal delivery.
AC-DC circuit board and power amplifier circuit board connector.
The internal structure of the lower cavity, the power amplifier circuit board is fixed by screws.
The 5 tweeters are respectively connected to the power amplifier circuit board through wires.
The external interface used for debugging is connected to the power amplifier circuit board through a cable.
Remove the screws and lift off the power amplifier circuit board. On the other side, there is a tweeter unit and a temperature and humidity sensor cable connected to the power amplifier board.
The circuit on one side of the power amplifier circuit board.
The circuit on the other side of the power amplifier circuit board.
The metal plate connecting the upper and lower chambers also acts as a heat sink.
Remove the metal plate, set the power amplifier chip below, and apply heat-dissipating silicone grease to enhance heat dissipation.
Filter inductor for digital power amplifier.
Nippon Chemical 63V 1500μF capacitor x 2, the bottom is reinforced with glue.
Rubycon 63V 1000µF capacitor.
Tweeter unit power amplifier circuit, 5 tweeter units correspond to 5 independent power amplifier circuits.
The ADI SSM3515 is a high efficiency, single-channel Class-D audio amplifier with fully integrated digital inputs. The application circuit requires minimal external components and operates from a single 4.5V to 17V supply. When powered by a 12V supply, it can deliver 8.4W of output power to drive an 8Ω load, or 15.8W to drive a 4Ω load. When using a 17V power supply, it can provide 31.3W of power to drive a 4Ω load, and the THD+N is 1%.
The SSM3515 uses a high-efficiency, low-noise modulation scheme that eliminates the need for an external LC output filter. Even at low output power, this scheme provides high efficiency. From a 12V supply, the efficiency is 92% at 7W into an 8Ω load and 88% at 15W into a 4Ω load. Compared with other Class D architectures, the use of spread spectrum pulse density modulation can provide lower EMI electromagnetic radiation, usually above 100MHz. The digital input function eliminates the need for an external digital-to-analog converter (DAC).
Pickup microphone, sealed with black hard glue. A total of four pickup microphones of the same specification are mounted on the entire PCB.
The microphone pickup hole corresponds to the acoustic structure of the microphone on the cavity.
Silkscreen NSJ’s current sensing IC.
The TI PCM5242 is a monolithic CMOS integrated circuit containing a stereo digital-to-analog converter and additional support circuitry in a small QFN package. The PCM5242 uses TI’s advanced segmented DAC architecture to achieve excellent dynamic performance and higher clock jitter tolerance.
Screen printing 1XFF regulator IC.
TI TPS54560 60V, 5A Buck Regulator with Integrated High-Side MOSFET. According to the ISO 7637 standard, the device can withstand load-dump pulses up to 65V. Current mode control provides simple external compensation and flexible component selection. A low-ripple pulse-skipping mode reduces supply current to 146µA at no load. Shutdown supply current is reduced to 2µA when the enable pin is pulled low. the
Silkscreen S510 Schottky diode.
The MEMS microphone of Laser Engraving 802o KSM1 is used to monitor the audio of the woofer and make dynamic adjustments.
TI TLV320ADC3100 is a low-power, stereo audio analog-to-digital converter (ADC) used to convert analog signals captured by microphones to digital signals. The device supports sampling rates from 8kHz to 96kHz and has an integrated programmable gain amplifier that can provide up to 40dB of analog gain or automatic gain control (AGC). Front inputs with coarse attenuation of 0dB, -6dB, or off are also available. Integrates programmable channel gain, digital volume control, phase-locked loop (PLL), programmable biquad filter, and low-latency filter mode.
Silk screen PN IC.
Silkscreen 162 C2A IC.
TI’s ADS7138 is an easy-to-use 8-channel multiplexed 12-bit successive approximation register analog-to-digital converter (SAR ADC). Eight channels can be independently configured as analog input, digital input or digital output. The device has an internal oscillator for performing the ADC conversion process. The ADS7138 communicates through an I²C-compatible interface and can operate in autonomous or single-shot conversion modes.
TI TAS3255 is a high-performance Class-D power amplifier that supports 315W stereo output and 600W mono output power. The device features an advanced integrated feedback design and proprietary high-speed gate driver error correction (PurePath™ Ultra HD). This technology allows the device to maintain ultra-low distortion across the entire audio frequency band while delivering flawless sound quality.
The TI INA253 is a high voltage bidirectional zero-drift shunt monitor with a 2mΩ precision integrated low inductance shunt resistor. The INA253 monitors bidirectional current over a wide common-mode range of -4V to +80V, independent of the supply voltage.
Silkscreen LTt IC.
Another TI TLV320ADC3100 low-power, stereo audio analog-to-digital converter (ADC).
In the internal structure of the cavity, there is a bracket above the tweeter to fix the PCB board.
The tweeter structure inside the cavity after the bracket is taken out. The five tweeters are evenly distributed in five directions and fixed by the cover.
The inner structure of the cover is equipped with a metal layer to shield the influence of the high-pitched magnetic field on the power supply.
Tweeter structure.
Take out the 5 tweeters.
The bottom structure of the cavity is equipped with a sponge cushion corresponding to the position of the tweeter, and the middle cable is connected to the debugging contact.
The pickup microphone hole on the casing is protected by a dust-proof net.
The inner structure of the power input interface.
Molex connectors for power input interface wires.
Humidity and temperature sensor structure.
Humidity and temperature sensors.
The top structure of the tweeter unit is glued to fix the wires. There is a sponge pad on top for cushioning.
The bottom structure of the tweeter is equipped with a sound hole.
All components of Apple HomePod 2nd generation smart speaker.
Conclusion
Apple HomePod 2nd generation smart speaker adopts the same cylindrical design as the first generation in terms of appearance. Wrapped in a seamless sound-transmitting mesh, the overall look is simple and stylish, and can be well integrated into various home decoration scenes. A whole backlit touch panel is designed on the top of the fuselage, which can display different color fluctuations according to voice commands under working conditions, making the human-computer interaction more ceremonial.
The internal structure is exquisitely designed and the workmanship is exquisite. The main structure is divided into upper, middle and lower layers. The upper part is equipped with touchpad and motherboard unit, the middle is the woofer cavity, and the lower part is equipped with power module, power amplifier circuit board, 5 tweeters, microphone and temperature and humidity sensor, etc.The overall structure is not much different from the previous generation, but the glue is removed between the structural connections. Components are also connected by connectors, and all components can be teardowned and replaced separately, which is more convenient for assembly production and later maintenance.
The main hardware configuration, the motherboard is equipped with 37 RGB LED light groups, equipped with 3 TI TLC5955 RGB LED drivers. It adopts Apple Apple S7 processor, Apple custom silk screen 338S00925 power management IC, Apple custom wireless module and TI TPS56637 synchronous step-down converter, etc.
The power amplifier circuit board is equipped with 4 microphones to form a pickup array for intelligent voice interactive pickup. A bass equalizer microphone for monitoring the sound of the woofer. Corresponding to the 5 tweeters, there are 5 independent power amplifier circuits, and the ADI SSM3515 integrated digital input high-efficiency, single-channel Class D audio amplifier is used. The woofer uses TI TAS3255 high-performance Class D power amplifier, which supports 315W stereo output and 600W mono output power.
In other aspects, two TI TLV320ADC3100 low-power, stereo audio analog-to-digital converters (ADC) are used to convert the analog signal collected by the microphone into a digital signal. TI PCM5242 monolithic CMOS integrated circuit, TPS54560 buck regulator, ADS7138 8-channel multiplexed 12-bit successive approximation register analog-to-digital converter (SAR ADC), INA253 high-voltage bidirectional zero-drift shunt monitor, etc.
Source: 52audio
