Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic 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

supply voltage obtaining (4.2V,3A) from 12V car battery

Status
Not open for further replies.

yassin.kraouch

Advanced Member level 2
Joined
Jul 5, 2009
Messages
631
Helped
40
Reputation
80
Reaction score
40
Trophy points
1,308
Activity points
5,101
supply voltage

i would like to obtain (4.2 V, 3 A) from a car battery which deliver 12 V, how can i obtain this??
regards,
 

yassin.kraouch

Advanced Member level 2
Joined
Jul 5, 2009
Messages
631
Helped
40
Reputation
80
Reaction score
40
Trophy points
1,308
Activity points
5,101
supply voltage

euhh but this regulator can only deliver 1 A i need 3 A in output!!
 

Kral

Advanced Member level 4
Joined
Mar 28, 2005
Messages
1,326
Helped
280
Reputation
558
Reaction score
85
Trophy points
1,328
Location
USA
Activity points
13,417
Re: supply voltage

yassin.kraouch,
You could use a linear regulator, such as the LM317, with an external pass transistor. See the app notes for the LM317 at http://www.national.com/ds/LM/LM117.pdf.
However, keep in mind the power (23.4 Watts) that the pass transistor must dissipate. You would need a fairly large heat sink to keep the chip temperature of the pass transistor less than 150 deg C. A more efficient solution would be a buck switching regulator. You can find lots of reference designs for this type regulator on the web.
Regards,
Kral
 

pranam77

Advanced Member level 5
Joined
Apr 22, 2008
Messages
2,786
Helped
552
Reputation
1,102
Reaction score
371
Trophy points
1,363
Location
INDIA
Activity points
16,411
Re: supply voltage

Here is a boost regulator circuit using LM317. You may use this circuit to get the 4.2Volts, 3A. Adjust the variable resistor to get the required volatge at the output. Hope it helps you. Do not forget the "helped me" button. Good luck.
 

akswami

Junior Member level 2
Joined
May 29, 2007
Messages
20
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,283
Activity points
1,372
Re: supply voltage

Ld29300 CAN ALSO BE USED
 

Audioguru

Advanced Member level 5
Joined
Jan 19, 2008
Messages
9,084
Helped
2,112
Reputation
4,218
Reaction score
1,938
Trophy points
1,393
Location
Toronto area of Canada
Activity points
57,057
supply voltage

An LM350 is an adjustable 3A regulator.
An LM338 is an adjustable 5A regulator.

They both reduce the current if they get too hot then shutdown.
 

treitmey

Member level 1
Joined
Jan 22, 2008
Messages
38
Helped
4
Reputation
8
Reaction score
0
Trophy points
1,286
Activity points
1,510

yassin.kraouch

Advanced Member level 2
Joined
Jul 5, 2009
Messages
631
Helped
40
Reputation
80
Reaction score
40
Trophy points
1,308
Activity points
5,101
supply voltage

ok thank you all, but a special thank to pranam77!!!! :)
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top