Re: Help on Bandgap Startup
You charge the CgsMS through R, so if you delay the charging of Cgs of current mirror, the current that charges CgsMS through R is larger. Because less current leakage to current mirror.
When you start to ramp up, MS is on and the current of bandgap grows, then this enlarges the current in your start-up circuit's current mirror. Unfortunatly, the latter draws more current through R that meant to charge MS. So if you delay the current of current mirror, MS is charged faster.
By the way, shouldn't we apply a step function(i mean a shorter rise time under SPICE) for the vdd to simulate the start-up of bandgap??