Along with the rapid development of portable audio applications like Bluetooth headsets and wireless speakers etc., the market requires audio processing chips that achieve the demands of low-power consumption and high resolution. This article will introduce LC82345x audio processing System on Chip (SoC) launched by ON Semiconductor to help you know the product features and advantages.
Audio SoC solution can reduce power consumption and improve efficiency
The market of portable audio applications has risen in recent years. Products such as sound recorders, wearable audio players, Bluetooth headsets, smart phone accessories and wireless speakers etc., are all popular in the market. This kind of portable audio product requires compact construction, longer audio play time and audio performance with high resolution. To achieve the goals, it is required to adopt high-integration large scale integration circuits (LSI). In order to meet customers’ demands, ON Semiconductor launches LC82345x audio processing System on Chip (SoC) for solving the challenge. LC82345x product series includes two types of chips now, the LC823450 and LC823455.
The LC823450 is a kind of SoC with ultra-low power consumption, 32-bit and 192 kHz high resolution audio functions. It is composed of dual ARM® Cortex®-M3, 32-bit DSP (LPDSP32) core, hard wired MP3 encoder / decoder and integrated SRAM. It is also equipped with analog peripheral functions such as PLL, D-type stereo HP (Headphone) amplifier, 6-band equalizer and ADCs/DACs. Matching the exclusive LPDSP32 of ON Semiconductor, it supports noise/echo cancellation and can provide play speed control function for MP3, WMA, AAC and PCM audio with VBR function. Through fine-tuning power management and exclusive hard wired audio block, LC823450 can provide longer battery life for voice recorders and wearable audio applications without influencing audio quality.
The LC823450 has built-in SRAM of 1656K bytes，support the I2S interface of 16/24/32 bit and the maximum of 192 kHz (2 channel x 2) audio functions. It also has various original DSP codes used in audio processing like MP3 encoders and decoders, FLAC encoders and decoders, noise cancellation and variable speed playback etc., hard wired audio functions like built-in MP3 encoders and decoders, EQ (6-band equalizer) and ASRC (asynchronous sampling rate converter) etc., as well as integrated analog functions like low-power Class D HP amplifiers, system phase locked loops, exclusive audio PLL and ADC etc. Except for various interfaces like USB2.0 HS device / host (not OTG), eMMC, SD card, SPI and I2C etc., it also has oscillating controllers to achieve dynamic switch of clock frequency, provides the maximum frequency of 160 MHz@1.2V and 100 MHz@1.0V for ARM Cortex-M3 dual cores and the 32-bit fixed point and dual-MAC original DSP aiming at audio processing.
The advantage of the LC823450 lies in the parallel processing supported by dual core and DSP with 32-bit 192 kHz high resolution audio processing capacity, free offer of various DSP codes like noise cancellation and variable speed playback etc., which can reduce DSP code development cost and achieve large scale programs via mass memory. It conducts low-power consumption audio processing via hard wired audio functions (e.g., only 4 mA is required for 128K bps and 44.1 kHz MP3 hardware play), reduces PCB space and cost via integration analog functions, supports Bluetooth audio with the functions like SBC/AAC encoders and decoders with DSP, UART and ASRC, reduces unnecessary power consumption via oscillating controllers for clock frequency switching, and provides higher processing capacity and clock frequency.
Another type of audio processing SoC, the LC823455 launched by ON Semiconductor as the updated variant of LC823450, also has high resolution 32-bit and 192 kHz audio processing capacity, provides key functions required by portable audio solutions including dual CPU configuration, provides DSP with intensive processing capacity as well as has built-in 4316 KB SRAM (used for supporting the realization of large scale programs of WLAN applications) and multiple interfaces (which can widely improve its connectivity). It has a wide range of functions such as SBC/AAC encoders and decoders and active noise cancellers which are suitable for various wearable audio applications and have rich set of high-integration analog functions to achieve ultra-low power consumption compact mini package. With the addition of high performance, it enables LC823455 with appropriate application in products like Bluetooth sport headsets, Bluetooth / WLAN wireless speakers, voice recorders and smart home appliances etc.
With the performance of ultra-low power consumption, the LC823455 adopts Arm Cortex-M3 dual core and proprietary 32-bit DSP core (LPDSP32) and has 4316 KB (4MB + 220 KB) built-in large scale SRAM, which supports high resolution 32-bit and 192 kHz audio processing capacity, shortens ambient acoustic sound path, provides multiple proprietary DSP codes for audio functions including MP3 encoders and decoders, SBC encoders and decoders, FLAC encoders and decoders, noise cancellation and echo cancellation etc., and provides hard wired audio functions like ASRC, EQ (6-band equalizers) and hardware mixers etc. The built-in analog blocks include 4-channel digital microphone PDM interfaces, low-power consumption Class D HP amplifiers, system PLL, dedicated audio PLL and ADC etc., which support USB 2.0 HS devices and have integrated PHY, eMMC and SD card interfaces as well as serial flash interface with high-speed cache, SPI, UART and I2C etc. Together with UART with DMA and FIFO, it supports low-power consumption Bluetooth audio and adopts small scale 4.086mm square WLCSP package.
The LC823455 is a single chip solution which can reduce BOM cost and does not require extra internal storage while running WLAN application programs. By enabling the ANC function and freely providing multiple DSP codes, it can reduce the development cost of DSP code, save power through reducing CPU/DSP load and save footprint through reducing peripheral BOM count, and improve interface extendibility with multiple interfaces.