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.

Instability on PWM Current Mode Controller

Status
Not open for further replies.

Draytek

Newbie level 5
Newbie level 5
Joined
Jan 7, 2010
Messages
8
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Visit site
Activity points
1,336
Hi,

I am trying to design a boost converter using the UCC28 part and im getting some suboscillation on the inductor current and FET Gate. I tried to compensate the slope by following the guidelines from the datasheet but I cant get rid of it completely. The intention is to run this converter in continuous mode for at least 20% or 30% of the full load (80V@300mA).

I dont see yet how to get rid of the suboscillation or if Im doing something wrong. I am actually thinking in setting it up for voltage control instead, to make it unconditionally unstable.

I attached the schematic in LTSPICE. The converter has been laid out with discrete components. The output cap has been reduced in order to speed up the simulation.
 

Attachments

  • LTSPICE.rar
    2.5 KB · Views: 104
Last edited:

As a first step, review your UC2843 model. Using a comparator with several 10 µs of response time in it looks like a joke.
 
Spot on mate!

I changed the comparator for a faster one and now is all clean and smooth.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top