How to become a senior digital IC Design Engineer (5-2) theory: ULP low power design technology (Part 1)

-- introduction
The performance characteristics of digital systems are always closely related to the execution speed and processing capacity of circuits , In the field of microprocessor design , Its performance is usually in accordance with MFLOPS（ Per second
Number of floating-point operations in time ） perhaps MIPS （ The number of executable instructions per second ） To measure .
However ,
Increased processing performance of digital systems ,
It means that the circuit load increases ,
therefore ,
---- Increased power consumption -> 
temperature rise , Affect the working state ) -> 
Reduced range , Impact on user experience ) -> 
Low stability , Impact performance potential ) -> 
Heat dissipation cost , Affect competitive programs )
Finally, it will affect the market promotion of products

Reliability is a function of temperature , It is estimated that every rise in temperature 10 The degree failure rate is doubled . Maintaining a low temperature operating environment means using heat sinks or fans to dissipate heat , But this will increase the overall weight and cost .

-- Definition of power consumption
---- Output power - Input power , In the field of electricity , Power refers to the work done by current in unit time ,P=UI, This may be a little abstract or conceptual
The power consumption of each part of a single display notebook is as follows ：
Notebook is W Of the order of magnitude
a main board 10
CPU 30
The graphics card 30
Hard disk 5
Memory 5
Monitor 15
Other 15
Smart phones are mW Of the order of magnitude
IP The design is uW Of the order of magnitude
---- Through the definition of power consumption, we can find , Power consumption is an instantaneous concept , It's unit time 1 Energy generated in seconds , And energy is a concept of time
for example , The power consumption of smart watches is 1mW, Work after running 30 minute , The energy consumed is 30*60s*1mW=1800J
---- yes PPA：Performance、Power、Area One of the compromises of

Abstract ： As PPA One of the members of , Low power technology is particularly important , The future IC One direction of design .
This paper mainly introduces some commonly used low-power design technologies, such as pipelined parallelism 、 Resource sharing 、 Status code 、 Gate clock 、 Operand isolation 、 Power consumption optimization of gate circuit 、 Multi threshold voltage .

-- Divide
---- Static power consumption (Static  Power)
---- Dynamic power consumption (Dynamic Power)
The next issue focuses on the meaning of dynamic power consumption and static power consumption