Weak current College】 【talk about low-power design】.

<br> Phenomenon: we this is 220V power supply system, there is no need to care about power problem <br> Comments: low-power design and not just to save power, more advantage reduces power modules and thermal system costs, reduced due .to current also reduces electromagnetic radiation and thermal noise interference. As the temperature of the device, the device life is extended accordingly (semiconductor devices operating temperature 10 degrees each increase, life is reduced by half) <br> <br> Phenomenon: the bus .signal with resistance pull, feeling at ease some <br> Comments: signal needs to be down for various reasons, but also not all want to pull. Pull-down resistor is a simple input signal, the current or following decades μA, La has .been driven by a signal, its current $ Ma-level, the system often address the 32-bit data, may have 244/245 for bus and other signals that are pulled up, a few Watts of power <br> Consumption, consumption in .the resistors on (do not use 8 cents was once the power of ideas to deal with these few Watts of power). <br> <br> Phenomenon: CPU and FPGA these unused I / O port how? let it empty, later < .br> Comments: unused I / O port if vacant, outsid little interference may be recurrent oscillation input signal, and power consumption for basic MOS device depends on the number of flip gate circuit. If you pull it, each pin will also have μA of .current level, so the best thing is set to output (of course it cannot add other driven signal) <br> <br> Phenomenon: the FPGA have left so many doors not finished, you can play! <br> Comments: power consumption .and by FGPA use trigger number and flip is proportional to the number of times, so the same model of FPGA in a different circuit different moments of power may differ by 100 times. Minimize the number of high-speed rollover trigger is to reduce the power .consumption of basic FPGA. <br> <br> In five: these small chip power consumption is low, regardless of <br> Comment: for internal less complex chip power consumption is very difficult to establish, it is mainly composed of PIN on current ., no load, one ABT16244 so power consumption is unlikely to 1 Ma, but it is the driver for each foot to 60 Ma of load (eg match scores of Ohm resistance), ie full load power consumption up to 60 * 16 = 960mA, .of course, this only supply current <br> Mody, heat fall to load. <br> <br> In six: memory have so much control signal, I use this Board requires only OE and WE signal, movie selection on the ground, .so that read operations when the data come out faster. <br> Comments: most storage power consumption when the movie selected valid (no matter how OE and WE) are selected than tablets is not valid for more than 100 times bigger, so it should .be possible to use CS to control chip, and meet other requirements as short films selected pulse width. <br> <br> Phenomenon of seven: how these signals are overshoot? as long as the match well, you can eliminate <br> Comments .: with the exception of a few specific signals (such as 100BASE-T, CML), are overshoot, as long as it is not very large, and not necessarily need to match, even if the match is not the best to match. Like .TTL output impedance 50 ohms, even 20 ohm, if also used such matching resistance, current, very large, power consumption is unacceptable, and another signal amplitude is so small that can not be used, besides General signal at the output and the output low .level output impedance is not the same, there is no way to do an exact match. So on TTL, LVDS, 422, signal match whenever possible overshoot is acceptable. <br> <br> In 8: reduce power consumption are hardware personnel, .and software that's OK <br> Comments: hardware just take a stage, Opera is software, bus on almost every chip access, each signal and almost all of the flip control by the software, if the software can reduce the number of out-of .-core access (using the register variable, use the internal CACHE, etc.), a timely response to interrupt (interrupt are often low level effective with pull-up resistor) and other specific disputes <br> Specific measures are veneer will reduce power .consumption make a significant contribution. <br>.