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

Problem with leakage in power MOS for LDO regulator

Status
Not open for further replies.
M

mitgrace

Full Member level 6
Joined
May 8, 2004
Messages
367
Helped
6
Reputation
12
Reaction score
2
Trophy points
1,298
Activity points
2,526
A power MOS for LDO

Dear All :

I have design the LDO regulator , and our PMOS is external componet , But now the LDO is wrong behavior , Becasue the PMOS gate induce some leakage , so that the OP amp can't work well . Does anyone know how to solve this problem , Or anybody know which POwer MOS is good ?

PS , I use SI2301 .

Thanks
 

Re: A power MOS for LDO

try to add the current of OP last stage :wink:
 

A power MOS for LDO

Excuse me , You mean add current buffer , How do design this , Do you have paper ,or schematic , Thanks
 

Re: A power MOS for LDO

8) i think it is due to noise, just add one resistor of around 100K from gate to source and check.
 

Re: A power MOS for LDO

sorry .. how large leakage current about your powerMos ??

as I know power Mosfet Ids =6A Cgs=1000p leakage = 0.1ua (Vds=0
Vgs =20v) or SI2031 have large leakage current ..
 

A power MOS for LDO

Dear All :
I Summary my measure result , I don't add the current buffer bwtween the OP and Si2301 , Now I mean the Open loop of OP , The Behavior ir right , But When I coonet to the close loop , the Behavior is wrong , the V+ is 1.8v , V- is 1.2 form Bandgap , the the the out of OP is 0.777v , So that I measure the stand alone the PMOS , I add a big resistor(7M) in the Gate , and I force the volatge(2.2) to Resistor , then measure the Gate volatge is 0.77v, It seem the Gate have some leakage cuurent , That I measure it , My questions is How do force my LDO to correct DC mode , Thanks
 

Re: A power MOS for LDO

PS . Our system is 3.3v convert 1.8v , We use 3.3 MOS to design this LDO regulator , Thanks
 

Re: A power MOS for LDO

There are flowing you should measured:
1. you can measure the leakage current by an amperemeter, how much?
2. measure the output by ac, maybe the close loop is osc.
3. test the output Pmos vth
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top