startup circuit for bandgap reference

[rsashwinkumar]

Hi all,
I am designing a bandgap reference circuit, which i have tested using Cadence Spectre. The circuit works well and converges to the designed operating point without a startup circuit, which wont be the case, when fabricated. The problem now is, if i design a startup circuit, i dont know how to test its working, as the circuit without the startup settles at the designed operating point. So i would not know, if the startup circuit is working properly. Is there any way in Cadence to test the circuit with startup ?
Plz help me out...

 

[keith1200rs]

Add some deliberate leakage (a very low current source or large resistor) to prevent it starting. Then add the startup circuit and check it does start. You may be able to do it with "initial conditions" although I usually add deliberate leakage.

Keith

 

[prestonee]

I was able to find the other bandgap's stable operating condition (0V output) by changing the temperature of the sim. and then used the startup to ensure the transient sim came out of this condition, the change in temperature basically added leakage, just another method to reach the same condition.

 

[rsashwinkumar]

@keith1200rs : Thank you... I figured out the initial condition settings, and now got the 0V operating point! Now will check out my startup circuit...