Saturday, 22 September 2018

Power Down States

1. Domain Isolation      2.Cross Domain Forward Bias Leakage


Domain Isolation

When domain powers are switched separately, signals between them must be properly isolated. Isolation networks are often complex, having domain crossings and distribution schemes of their own.
Insight Analyzer enforces isolation only where it’s actually needed. You can now check the integrity of the complete isolation network: Control inputs, logic states, isolation level shifters, and more.

Checking Isolation Stages

Insight Analyzer checks the point of crossing for cases of:

  • Isolation cell is faulty.
  • Isolation is not present (raw signal).
  • Control signal is missing.
  • Power states do / do not require isolation.
In this example, user hard-tied a good isolation cell to permanently enabled (using it as a plain level shifter).
Later, the design architecture changed, and a power state was added.

It appeared that the isolation was appropriate, but in fact it was leaking internally.
Insight Analyzer detected this case and reported as a clear violation.

In this example, isolation cell was not properly designed. The isolation clamp function was put only at the output. There was no power cut or clamp function in the level shifter core. So, the isolation cell:
Did function correctly in simulation.
Was leaking current internally!
Insight Analyzer detected this case and reported clear violation to the user.

 

Cross Domain Forward Bias Leakage

When a domain is powered down, there can be a leakage path through forward bias body diode. Insight Analyzer finds these cases and reports the cause.
UPF / power state combinations are used to focus the results for accuracy. Only the true cases are reported.

 

Leakage between domains.
Complete description is given. User can trace every step in schematic cross-probe, from higher rail to lower/off rail.

 


InsightEDA provides software to fill an unmet need in the Electronics industry.

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