Stats

  • Locked Locked
  • Replies 2
  • Subscribers 125
  • Views 8919
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Describe the peak current method [Verilog-A]

YYLee

Hi all 

I have a question about the current behavior.

How to describe the peak current?

For example, we have an inverter (A->Y); when the input value (A) rising to the Vth of the inverter, the nmos/pmos will be open. Consequently, a current suddenly flow to ground.

The solution i found is that: 

-----code-----

integer peak_moment=0;

if(V(A) > Vth) peak_momnet=1;

if(peak_moment==1)begin

I(vdd) <+ 2.5uA;
peak_moment=0;

end

-----------------

is it right? is it weird?

 

Furthermore, the peak current decided from the  circuit which peak in different moment and value.

So, is there have suitable way to describe the current peak in verilog-A logic ? really thank you!!

Parents
  • ShawnLogan

    Dear YYLee,

    YYLee said:

    How to describe the peak current?

    For example, we have an inverter (A->Y); when the input value (A) rising to the Vth of the inverter, the nmos/pmos will be open. Consequently, a current suddenly flow to ground.

    I may not understand your question. However, if you are trying to determine the peak supply current for a conventional CMOS inverter, your comment "when the input value (A) rising to the Vth of the inverter, the nmos/pmos will be open" does sound quite accurate to me. As the input voltage to an inverter approaches its threshold voltage (the voltage threshold of the inverter - not the individual threshold voltages of the PMOS or NMOS device themselves), both the NMOS and PMOS device will conduct current and will not appear as "opens". The DC and transient responses are the supply currents are shown in the attached file.

    As a result, I apologize, but do not understand what the goal of your model is trying to provide. Sorry!

    Shawn

Reply
  • ShawnLogan

    Dear YYLee,

    YYLee said:

    How to describe the peak current?

    For example, we have an inverter (A->Y); when the input value (A) rising to the Vth of the inverter, the nmos/pmos will be open. Consequently, a current suddenly flow to ground.

    I may not understand your question. However, if you are trying to determine the peak supply current for a conventional CMOS inverter, your comment "when the input value (A) rising to the Vth of the inverter, the nmos/pmos will be open" does sound quite accurate to me. As the input voltage to an inverter approaches its threshold voltage (the voltage threshold of the inverter - not the individual threshold voltages of the PMOS or NMOS device themselves), both the NMOS and PMOS device will conduct current and will not appear as "opens". The DC and transient responses are the supply currents are shown in the attached file.

    As a result, I apologize, but do not understand what the goal of your model is trying to provide. Sorry!

    Shawn

Children

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.