Inspiration from the personalized design of portable products in the era of Datong

When the so-called "copycat phones" that flood the domestic mobile phone market move towards large screens, stereo amplifiers, touch controls, and even GPS navigation and mobile TV, the homogeneity between "copycat phones" and "branded phones" is becoming more and more serious. Mobile phones are just a microcosm of the portable product market. The MP3, PMP and PND product markets are all caught in a fierce price war caused by homogeneous competition. If you want to step out of the quagmire of low-price competition, using technological innovation to support differentiated competition may be the only effective way. From interviews with some portable product chip design companies, we also found that there is still a lot of room for improvement in terms of improving product performance, reducing power consumption or functional innovation.

Audio CODEC with integrated DSP

A common phenomenon in the portable product market is that homogeneous products force manufacturers to engage in price wars in the market, and price reduction comes at the expense of quality. In addition, portable products are facing the problem of compromise between quality/function and power consumption, among which the quality of audio processing is also constrained by battery life.

The important means of achieving product differentiation in the current music mobile phone market is 3D surround sound, but due to the size of the mobile phone, stereo effect cannot be achieved by simply adding speakers. Some stereo music mobile phones even use 6-channel speakers, but they cannot achieve stereo effect. This is because the distance between the two speakers is relatively close. Usually, the distance between the two speakers is 30 cm to achieve stereo effect.

Zhang Hongwei, business development manager of high-performance analog products in TI China, explained that if some stereo equalization algorithms are run at this time, this effect can be easily achieved, but running such algorithms in the application processor will make the workload huge, or require special personnel to supervise the algorithm. Therefore, a small DSP can be added to the design of the audio CODEC, allowing the mobile phone to release MIPS on the application processor while running complex algorithms. For example, TI has integrated a 110MIPS miniDSP in the latest TLV320AIC3x series of audio CODECs.

The advantage of having a built-in DSP in the CODEC is that a complete algorithm library can be added to the DSP algorithm to optimize audio performance, such as echo cancellation, stereo equalizer, dynamic range compression, bass enhancement, and loudness compensation. In order to combat noise, a stereo amplifier with dynamic range compression can be used to amplify small signals and reduce large signals, resist noise interference, and make the average loudness smaller. A typical application is car navigation with very loud noises. In order to ensure clear navigation, designers usually increase the stereo power of GPS navigation equipment to 1W or 2W. Some large-sized GPS even have a power of 3W to 5W, which is unaffordable for portable devices.

To address the power consumption issue, different operating modes can be used to mimic the power consumption design of the processor, allowing designers to make a trade-off between low power consumption and signal-to-noise ratio, such as TI's PowerTune technology. PowerTune first uses the processor to accurately understand the signal-to-noise ratio of the audio to be played in advance, such as setting the power consumption of stereo ringtones as priority, and setting the playing of English learning materials to the lowest power consumption mode. The CODECTLV320AIC3254 with PowerTune technology can optimize the power consumption to 2.4 mW in any usage mode in stereo playback, and the power consumption is 5.1 mW when playing high-fidelity music with a 100dB signal-to-noise ratio.

Figure 1 Low-power audio CODEC with integrated miniDSP

Portable projectors step out of the conceptual era

While improving audio quality, the industry is also seeking visual breakthroughs in portable products. On November 3, Wingtech, the largest mobile phone design company in China, announced that it would cooperate with Taiwan's LCD driver chip manufacturer Himax to promote LCoS (liquid crystal on silicon) projection mobile phones in the mainland market. Considering the micro-projection chips that TI demonstrated at the Mobile World Congress 2008 held in Barcelona, ​​Spain in February this year, which can be integrated into various mobile devices, it can be seen that due to the limited size of mobile phone screens, the significance of mobile phone projection lies in breaking through the limited experience of the narrow mobile phone screen, so that non-private information has a better way to experience, share and display.

Figure 2: CKING projection phone launched by Shengtai uses LCoS projection module from Red Butterfly Technology

In fact, many companies have already started to develop key chips for micro projectors. In addition to TI and some LCD driver chip design companies, companies focusing on display and optical technology such as Djin Display, Micro Precision, Microvision, Upstream Engineering, etc. have achieved research and development results in the development of micro reflective lens MEMS. Mobile phone and projector manufacturers such as Nokia, Motorola, Samsung, and Canon have also successively developed micro projection components that are a few millimeters thick and a few centimeters in size. At this year's Tianjin Mobile Phone Exhibition, China's Shengtai Technology also launched the world's first projection mobile phone with the support of optical device and optical module manufacturer Red Butterfly Technology.

Figure 3 TI's DLP chip for portable projectors

In terms of digital imaging processing technology for mobile phone projection, TI's independently developed DLP (digital light processor) technology has been verified in the projection display market, accounting for more than 30% of this market share. Its core is the digital micromirror device (DMD), which is composed of millions of microscopic mirrors and acts as an optical switch. Each mirror can flip back and forth (open or close) up to 5,000 times per second. The input image or graphic signal is converted into digital code, that is, binary data composed of 0 and 1. These codes are then used to drive the DMD mirror.

When the DMD base plate works with the projection lamp, color wheel and projection lens, these flipping mirrors can reflect a seamless digital image onto the TV screen. A DMD is composed of many tiny square reflective lenses (micromirrors) arranged closely together in rows and columns, and then attached to the electronic nodes of a silicon chip. Each micromirror corresponds to a pixel in the generated image. The number of micromirrors determines the physical resolution of a DLP projector.

Yole Development of France and Chipworks of Canada jointly released a market report on optical processing cores and micro projectors. Chipworks analyzed the differences between TI's latest DLP devices and previous generations, highlighting its technological advances in wafer-level packaging and pixel size reduction. TI reduced packaging costs by replacing the original ceramic packaging with wafer-level packaging, and reduced chip area by reducing pixel size. Yole Developpements used reverse cost analysis and believed that the new wafer-level packaging technology would reduce costs by 50% (from about $400 to about $200).

Of course, TI's DLP advantage is also facing challenges from its competing technologies. The LCoS microdisplay technology used in the CKING projection phone mentioned above is one of them. Currently, dozens of companies in the world are actively developing this technology. Microvisions of the United States demonstrated a micro color projector using LCoS technology at the Globalpress Electronics Summit held in San Francisco in April 2008. Microvision's goal is to launch an independent micro projector with a price positioning of US$400 to the market in the fourth quarter of 2008, and to reduce the price to US$100 within five years. Micro projection modules integrated into mobile phones and laptops are also under development, with a target price of less than US$100. [page]

LCoS is a new digital imaging technology. Its basic imaging method is similar to three-chip LCD technology. However, the light of projectors using LCoS technology is not transmitted through the LCD panel, but is reflected to form a color image. It uses a CMOS integrated circuit chip coated with liquid crystal silicon as the substrate of the reflective LCD. It is polished with advanced technology and plated with aluminum as a reflector to form a CMOS substrate. The CMOS substrate is then bonded to a glass substrate containing a transparent electrode, and then injected with liquid crystal packaging. LCoS places the control circuit behind the display device, which can improve the light transmittance, thereby achieving greater light output and higher resolution. The color gamut of the LCoS projection chip is very wide, and its color gamut range is much larger than that of CRT and DLP chips.

Compared with DLP, which is a fairly mature technology, LCoS can only be considered in its infancy. Because LCoS display technology involves multiple cutting-edge technologies, mainly VLSI design and production processes, liquid crystal related technologies, optical engine technology, new optical disc technology, image processing related technologies, etc., it is difficult for a company to master all these key technologies. However, DLP and LCoS represent a new development direction of display technology, that is, the hybrid integration of micro-optical electromechanical system (MOEMS) technology and solid-state lighting (LED, HVBLED, or laser diode) is a novel and unique solution to achieve low-cost and compact optical engines.

Dual-core processors seize the mobile TV market

With the help of the 2008 Beijing Olympic Games, CMMB mobile TV was very popular for a while, but it seems to have lost its momentum in the post-Olympic era. Currently, there are two forms of TV programs: one is FTA (Free To All) without encryption, which usually covers public welfare or advertising content, which is not very attractive to ordinary consumers; the other is CA encrypted reception, including commercial media entertainment, interactive media playback and professional data broadcasting, etc. Such value-added services are charged service fees. As for whether joining the paid CA will affect the prospects of mobile TV, which is still in the development stage, the industry is still skeptical.

At least in the eyes of terminal vendors like Patriot, the advantages of charging for some content outweigh the disadvantages. Patriot's recently launched Walk TV CMMB digital TV receiving terminal integrates CA conditional reception, interactive playback and real-time data broadcasting. A typical application case of Walk TV is to use mobile digital TV data broadcasting to transform the voice reception of traffic information broadcasting into real-time video traffic information display.

What is a little surprising is that the processor used by Patriot's Walk TV is not the previous ARM-based Freescale i.MX platform, but the dual-core multimedia processor SSD1933 from Solomon Systech. SSD1933 is the latest product in Solomon Systech's MagusCore portable multimedia processor, integrating ARM926EJ-S and AV-DSP on a single chip. The feature of SSD1933 is that the optimized dual-core allocation structure reduces the power consumption during multimedia acceleration.

In fact, AV-DSP adopts CEVA's MM2000 multimedia solution. Through MM2000, SSD1933 can encode and decode video signals of various standards, including H.264 standard with the highest D1 (720x576) resolution at 30fps. Combined with MPEG-2 transport stream interface (TSI). The fully programmable architecture of MM2000 allows SSD1933 to support a wide range of video formats, including H.264, MPEG-4, WMV/VC-1, RMVB and H.263 with up to D1 resolution. In addition to the dual-core part, MagusCore also includes a 2D graphics accelerator, camera interface, 24-bit LCD interface and an NTSC/PAL decoder, designed for shooting and playing videos and photos.

The choice of single-core or dual-core processor architecture is more about the balance between solution flexibility and cost. According to Deng Guoyuan, CTO of Shenzhen Patriot, Patriot has been using Freescale's i.MX platform before. Its mature products include solutions based on the i.MX31 design, which is a processor using a 532MHz ARM11 processor core, integrated with a VGA resolution hardware video and image processor and a 2D/3D graphics accelerator, which can support the playback of video formats such as RMVB, MVA, AVI and VGA, as well as 30fps, MPEG4@VGA video recording. After that, in order to make up for the lack of i.MX processor's ability to support multi-format video encoding and decoding, Freescale also officially released the i.MX27 in 2007, which integrated the ARM9 and H.264, MPEG4 hardware encoding and decoding cores.

As for the dual-core solution of Solomon Systech, Patriot prefers to label this cooperation as "independent innovation". Patriot Shenzhen Research Institute started to develop a strategic cooperation with Solomon Systech to develop mobile multimedia digital TV solutions based on MagusCore in early 2007. Beijing Huaqi CTO Fan Wei said: "The joint research project mainly focuses on the development of core chips, mobile multimedia real-time operating systems, software and hardware collaborative mobile digital TV multi-protocol source decoding software packages, and application software packages. It is a collaboration of three levels: application, software and chip." Both parties define this cooperation as "chip design starting from system application to complete embedded system software".

Figure 4 Mobile TV terminal based on MagusCore