About overshoot of the bandgap reference

[jonneylu]

Hi friends:
The bandgap reference based on two-stage amplifier always start up with overshoot about 0.2V,but the loop phase margin is enough,i dont know why?
thanks a lot!

 

[ambreesh]

Do an AC analysis with IC forced at nodes.
You will observe different behaviour.

 

[abcyin]

Do an AC analysis with IC forced at nodes.
You will observe different behaviour.

Er... What's your meaning by "IC forced at nodes", thx in advance!

 

[ambreesh]

Give intial conditions to nodes, voltages they would start from.
Then run AC analysis

 

[sina25]

What do you refer to overshoot to? Please, explain me.

Thanks

 

[surianova]

What do you refer to overshoot to? Please, explain me.

Thanks

do u ramp up your power supply when simulate ?

 

[ambreesh]

Depends on the system if you want to apply a simulation with supplu ramp.
If you have a power down for your BGR then the supplu would appear as a step to the BGR.

 

[chungming]

When circuit start-up the opamp may not in the right region
so feedback loop is not active.
you can add some cap let the opamp work slowly.
like the attached picture.....