Re: Cascode Bandgap
first, M3 an M5 is used to bias the mp1 and mp2,respectively,which is very necessary for low power supply applications,because the voltage drop across the whole cascode current mirror is only 2 times Vov. that's to say, if the power supply voltage is large enough, you can use other structures to replace M3 and M5.
second, i think the start-up circuit is not good. in my opinion, it's difficult to turn off the current-injection banch. i suggest you use other start-up structures. there are many simple start-up structures.