职务:意法半导体(STMicroelectronics)深圳设计中心的高级工程师,主要负责基于低功耗的SoC设计方面的工作。早年毕业于英国谢菲尔德大学(University of Sheffield)的电子工程系,获得了理学硕士学位。曾在北京的六合万通微电子有限公司参与了基于ARM7TDMI内核Wireless LAN802.11bMAC芯片的开发工作。之后又在意法半导体深圳设计中心主持了基于多种内核,用于多种无线通信终端的SoC的设计工作。现在则主要负责SoC芯片的系统架构设计以及项目管理的工作。在SoC设计方面积累了丰富的经验,特别擅长基于ARM内核的SoC设计以及低功耗设计。
读者Huang Zhaohui提问:Hi Mr.Jiang: I'm a member of the SoC design team from MSU and we are working on a low power SoC design project for SRC/SIA design contest (3rd place in phase I out of 39 teams).
For low power mixed-signal SoC design, analog components dominate the total chip power consumption in many cases. Not like digital, which can be controlled by voltage/frequency scaling, analog building blocks are relatively hard to be turned on and off while maintaining good performance. My idea is let the digital processor core perform the power control/management for the analog portion and reconfigure them to achieve the best power/performance trade-off. But this introduces two problems:
First, it will increase the workload of the processor core(low usage for processing work)
Second, the analog circuitry needs to own adaptive architrave/features to allow the reconfiguring mastered by digital. This means more design efforts and longer design cycle.
Conventional board level design usually has stand along power management chip. However, the difficulties of integration the PMU and implementation of on-chip DC-DC converter limit the SoC design option.
Things become even worse when integrating RF stuff on the chip. They are maturely power hungry. But we have to consider all these in order to build a real system-on-chip. Or we have to go for the SIP(system in package) solution.
What is your low power SoC design strategy in STMicro.?
蒋燕波先生的回答:Hi, Mr Huang, It is really very nice to see your email and congratulations for your team got a very good rank in SRC/SIA contest.
It will be very happy to dicsuss the low power design knowleadge with you, but firstly let's remove the company name from our discussion and what I can shared with you is base on my personal opinion. Yes, the problem you mentioned is a challenge for every low power SoC designer, and it is very hard to give expression of low power strategy in several words. As you mention in your email, for digital design, we have a lot of way to cut the power consumption down, but when we have some analog blocks or RF blocks, thing will be very challenge. I think in most project, we need to analyse case by case. Sometimes the analog block can be switch on/off, but sometime can not, it does not only depend on the design of analog block, but also depend on the application of the SoC. For example, a for a FHSS RF/IF tranceiver chip, the PLL need to be locked as quick as possible, if our the PLL switching on and locked time can not satisfy the FHSS function, then we will not be able to use this "switch off" power save scheme.
I think for a SoC design who has a strict requirement on power consumption, we need to do power plan from bottom to top very carefully. In sub block side, we need to define the power saving capability for each block, maybe be different power saving mode, fast switch on/off capability or fast convergence capability. In system level, we need to plan the power control/managment function according to application. Finally, we need to use some power analysis/simulation tools such as primepower or power compiler to verify our power saving method.
Low power design is a critical issue in most of the pocket/wireless application, but this is also a chance for designer to show their creativity, hope we can have more discussion in detail. Thanks for your email.
读者Christy提问:I am majoring in Electrical Engineerinag now. I need to design a PCB recently. Can you tell me how to start? I need to design the PCB with receiver and transmitter. The PCB is used on my vehicle. The vehicle is controlled by itself. I am not sure if I can get your reply. I am looking forward seeing your emaill. Thank you for your time.
蒋燕波先生的回答:Him Christy,
Thanks for your email. I am not a expert on PCB design and layout, maybe my suggestion will not be very useful for you. Just give you some rough ideal on the procedures of PCB design:
(1)Schematic library and PCB layout library generate. You need to build up all library which is not including in your PCB design tools library. (2) Draw schematic. Design the circuit according to your idea. (3) PCB placement. Place all devices in right place. (4) PCB rounting. Connected all device according to your schemaic.
These are normal procedures of PCB design. When you start your job, you should choose a popular design tools, such as Protel or PowerPCB, it will make you feel easy to find the manual and instruction of these tools. Of course, there are a lot of techniques on PCB design, especially on high speed PCB design. For further detail information please visit discussion page of Mr. Bolong Li:
用户992653 2007-1-10 17:54
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