Chris
03/10/2023, 8:41 PMBoris Murmann
03/10/2023, 8:48 PMLuis Henrique Rodovalho
03/10/2023, 9:51 PMChris
03/10/2023, 9:52 PMPZ
analysis and yes there is an RHP zero ~ 3.7e4 Hz canceled with an LHP pole ~ 2.8e4 Hz. I further verified their stability in transient analysis and yes the second situation circuit oscillated. Guess I need to push that RHP zero to the left plane somehow. More often I see a zero-pole pair (or doublet in closed-loop) as an LHP pole + an LHP zero but not with an RHP zero. Miller compensation without a null resistor generates an RHP zero, parasitic Cgd has a RHP zero; are there in general other situations where this LHP pole + an RHP zero occurs? Thanks.Luis Henrique Rodovalho
03/10/2023, 9:56 PMBoris Murmann
03/11/2023, 12:19 AMChris
03/11/2023, 12:32 AMxschem
installed). The first schematic is EA, the second one is EA with the PMOS pass transistor, and the last one is the loop stability testbench of the LDO. In the pictures I attached before, the first one is at which the load current is 10mA and the second is load current=10uA. It has a stability problem when the load current is small. Sorry if those wire connections are messy as I am still changing things back and forth.Boris Murmann
03/11/2023, 12:38 AMChris
03/11/2023, 1:13 AMBoris Murmann
03/11/2023, 1:19 AMChris
03/11/2023, 1:31 AMBoris Murmann
03/11/2023, 1:44 AMLuis Henrique Rodovalho
03/11/2023, 7:33 AMBoris Murmann
03/11/2023, 2:48 PM