Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Regarding line regulation of LDO

Status
Not open for further replies.
N

nagateja

Newbie level 6
Joined
Jan 30, 2017
Messages
12
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
103
Hi,

I designed a LDo votage regulator with input voltage of 1.8 V and 100mA load in 180 nM tech. in cadence. I am getting all the parameters like Load regulation, slew rate, dropout voltage, Iq very accurate. but iam not getting line regulation. if i change the input voltage, output also changing (Drop is constant).

Please help me to get the good line regulation.
 

Hi,

It´s impossible to give a good answer with the given informations.

What is the expected output voltage?
How do you regulate the output voltage?
Do you have enough headroom? What´s the expected (calculated) dropout voltage with full load?

Show us your schematic.

Klaus
 

KlausST said:
Hi,

It´s impossible to give a good answer with the given informations.

What is the expected output voltage?
How do you regulate the output voltage?
Do you have enough headroom? What´s the expected (calculated) dropout voltage with full load?

Show us your schematic.

Klaus
Click to expand...

Thank you for reply.

my expected output is 1.7 volts. at full load of 100mA i got dropout voltage of 85mV. I got perfect load regulation but not line regulation. i am attaching schematic of LDO for your reference
 

Hi,

Is the LDO error amp a differential pair + output stage, and is that supplied by the main input supply, or does it have it's own (Bandgap) reference and supply (the internal LDO to power the external LDO...)? Without a reliable "inner guts" supply voltage the line regulation will follow the input supply, assuming the MOSFET isn't the wrong way round - easy to do by mistake :).
 

You might probably be having a pretty bad PSRR or the reference is changing with the supply. Please provide the circuit details.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top