Question about line regulation graph of LDO

[arielski3]

hi Guys,

i am currently doing an evaluation of LDO and im trying to get the line regulation graph. since im varying my supply voltage,say 6V to 20V, over a load current, i would expect my output voltage to rise. however, this is true only for current load less than 150mA. when i increase my current load further say 200mA, my output voltage rise from 6V to 15V and from 16 volts it started to decrease.. so what seems to be the reason behind the decrease of my output voltage from 16V to 20V? by the way, the LDO was designed for voltages until 20V and max current of 300mA.

thanks

 

[aggpankaj2]

Re: Line Regulation(LDO)

it seems to be going into constant current mode.. its better if you can share some schematic etc. for getting more onto this problem..

 

[arielski3]

Re: Line Regulation(LDO)

kindly see attached for the block diagram.. block diagram is all i got..

 

[aggpankaj2]

Re: Line Regulation(LDO)

no attachment... ???

 

[arielski3]

no attachment still? any way, what are the conditions in order to say that the circuit enters constant current mode? and what is constant current mode means? thanks.