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.

PS with LM76003 for variable volatage and variable current design?

Status
Not open for further replies.

Javert

Member level 2
Joined
Sep 14, 2019
Messages
44
Helped
0
Reputation
0
Reaction score
1
Trophy points
8
Activity points
551
LM76003 is 3.5A Synchronous Step-Down Voltage Converter.
I want to use it for design power suplly with variable output voltage 1-45 with with current range near 0 to 3,5A.

My operating conditions:
Input vopltage 50V.
Switching frequency 350-500kHz
Output voltage 1-42V
Output current tens of mA - 3,5A
And I have a few questions.,

1.Choice of output coil and capacitors.
Output coil.
Due to the large output current range I oversized it and even at a high switching frequency I consider 47uH 4.5A

2. Output capacitors.
I thing SMD ceramic 2x 47uF 100V size 1812 + 8x 10uF 100V size 1210 = 147uF in SMD ceramics, plus any small 100nF/330nF.
It is recommended to use more capacity in ceramics or add aluminium for example 470uF LXZ ?
 

When you draw high power your output capacitors have to carry 1 or 2 Amperes per cycle. That's thousands of times per second. It may be all right to have a gang of several surface mount capacitors as listed in your specs.

If you attach very large uF, then it may draw large surge current at power-up.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top