On Mar 3, 2013, at 7:50 AM, Narayana Bhagirath T wrote: > I have designed an 8-bit ADC using Electric and LTSpice. I wanted > to know if the power consumption of the circuit can be obtained directly > from the plot Vcc*Icc? Is there any other procedure for calculating the same?
I have found that attempting to calculate the area under the current-vs-time plot does not always yield reliable results. Likewise for repeatedly calling "ni" at the interactive prompt in HSIM. I think when you plot currents you're getting an approximation, and each plot point is the instantaneous current at some arbitrary time in the nonzero time interval that the plot point represents. But there could be some other explanation. There are various tricks you try with current-controlled voltage sources and integrating current on an ideal capacitor, but CCVSes with complex equations often cripple the optimizations in high-speed SPICE engines resulting in a 10-100x slower simulation time. On the other hand ".measure" works very well for me: Vsupply vdd gnd DC 1.0v .measure tran totalcurrent INTEG I(vsupply) FROM=0n TO=99999n ... then at the end of the simulation you'll get a line for "totalcurrent" in your ".mt" file. Multiply that by the supply voltage to get total energy consumption; divide it by the simulation time to get average power. So, use ".measure". Don't try to compute power consumption from plots. I wasted at least a week trying to get reliable numbers that way and encountered only frustration. -- You received this message because you are subscribed to the Google Groups "Electric VLSI Editor" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
