what the power vaule means in Libray Compiler ? uW/MHZ?

min_pulse_width_low

Hi,All:

what the power vaule means in Libray Compiler ? uW/MHZ or other ?

Best Regards!

what is setup_rising

The power dissipation (dynamic) is given by
Pdyn=C*Vdd^2*P*f the ratio Pdyn/f is the number you are asking.

setup_rising

thanks you.That means that if I the value is 0.1, it power is 10 unit if it is woking in 100MHZ, and the power is 20unit when it working in 200mhz?

Best Regards!

min_pulse_width_low clock

Exactly, usually libraries have an equation where you can caclulate the power dissipation of a digital circuit.

uw/mhz

Hi,
when I genearte RF2R2W power, I get I=5mA, worst case V=1.62v 200Mhz,so the power should be 5*1.62v=8.1mW, the value in the library should be 8.1/200=0.0405 mw/MHZ, I checked the compiled library it should should be 40.5, what the unit should be in compiled library ?

Best Regards!

internal_power unit

the power dissipation is connected also with the switching activity and the capacitance. Check your library there is an equation for power estimation. It is not that straightforward.

uw mhz

Hi,
Thant you , if I want to generate a library with power information,what should I do ?

Best Regards!

power uw/mhz

Hi,
The power I want to generate is internal_power.

Best Regards!

rise_constraint

What do you mean with internal power? Leakage or short circuit?

Hi,
It meas short_circuit power.
During switching, a circuit dissipates internal power by the charging
or discharging of any existing capacitances internal to the cell. The
definition of internal power includes power dissipated by a momentary
short circuit between the P and N transistors of a gate, called shortcircuit
power.


Best Regards!

I don't think that there is a reason for you to build a library with the short circuit dissipation of several digital circuits. If you the rise time and fall time of the gates are equal then the short circuit dissipation is minimized. I can cite you to a paper if you need further informations.

Hi,

Sorry,I am a little confuse of that. For a cell internal power may meas short circuit power,but for a circuit compose lots of cells, they are not the same definition. In my opition,it may meas dynamic power.
I have ftp some files ,include library and verilog code .It generate by memroy compiler. Please see the library file, the internal power problem is in there. thanks.


Best Regards!

Hi,
here they are.I can not ftp .lib file to you.If you want I will email to you later.
Here is the power description in libray file:
***************************************
pin(CLKB) {
direction : input;
capacitance : 0.070
clock : true;
min_pulse_width_low : 0.129;
min_pulse_width_high : 0.115;
min_period : 0.803;
max_transition : 2.100;
internal_power(){
when : "CENB";
rise_power(RF2SH_200_passive_energy_template_1x2) {
index_1 ("0.0 1.0");
values ("0.000, 0.000")
}
fall_power(RF2SH_200_passive_energy_template_1x2) {
index_1 ("0.0 1.0");
values ("0.0, 0.0")
}
}
internal_power(){
when : "!CENB";
rise_power(RF2SH_200_passive_energy_template_1x2) {
index_1 ("0.0 1.0");
values ("37.170, 37.170")
}
fall_power(RF2SH_200_passive_energy_template_1x2) {
index_1 ("0.0 1.0");
values ("0.0, 0.0")
}
}
timing() {
related_pin : "CLKA" ;
timing_type : setup_rising ;
rise_constraint(scalar) {
values ("0.413")
}
}
}
pin(CLKA) {
direction : input;
capacitance : 0.087
clock : true;
min_pulse_width_low : 0.158;
min_pulse_width_high : 0.127;
min_period : 1.114;
max_transition : 2.100;
internal_power(){
when : "CENA";
rise_power(RF2SH_200_passive_energy_template_1x2) {
index_1 ("0.0 1.0");
values ("0.000, 0.000")
}
fall_power(RF2SH_200_passive_energy_template_1x2) {
index_1 ("0.0 1.0");
values ("0.0, 0.0")
}
}
internal_power(){
when : "!CENA";
rise_power(RF2SH_200_passive_energy_template_1x2) {
index_1 ("0.0 1.0");
values ("62.377, 62.377")
}
fall_power(RF2SH_200_passive_energy_template_1x2) {
index_1 ("0.0 1.0");
values ("0.0, 0.0")
}
}
timing() {
related_pin : "CLKB" ;
timing_type : setup_rising ;
rise_constraint(scalar) {
values ("0.413")
}
} }

..........

Power could be decomposed into three parts:

Static power (leakage)
Dynamic: Short circuit
Dynamic: Charging /discharging the load (wire and gate)

p = c* v^2 * f
covered the third part.

Most of the libraries did NOT include the leakage.

The short circuit current affected by the input-signals' slope, cell design, and the processing...