UCC28180: Powering ON at the same time Leads to BOOM BOOM.

Hi Vyshanv,

Generally, you want the controller powering up first so it can do it's thing. 

Usually inrush current is controlled by an NTC resistor on the input.  The soft-start will help to a lesser extent.  If your system can handle a higher compensation, that will increase soft start time.

Also, make sure you have a diode from the bridge to the output (See D2 in fig 29 https://www.ti.com/lit/gpn/ucc28180).  This will shunt the start-up current past the MOSFET until the output comes up.

Regards,

Ray

Hey Ray !

The points you said have been noted, How can i make my control system better by improving the compensation, so that the soft start will be of higher period? Is there any way to understand the compensation circuit better?

with regards

Vyshnav

Hi Vyshnav,

To be clear, the NTC resistor and shunt diode are your primary tools for controlling inrush current.  The UCC28180 does not have a dedicated soft-start programmability pin but by effecting the rise of VCOMP, it has an inherent soft-start feature. The primary use use of the compensation network is to balance stability with transient response of the system (refer to sections 8.3.1 and 8.3.22 in the datasheet). 

To learn about compensation in general, watch this video keeping in mind that the UCC28180 is a boost converter with both current and voltage loops: https://training.ti.com/switch-mode-power-converter-compensation-made-easy?cu=1127730

I also want to point out that it is best to use the UCC28180 Design Calculator to help with your design: https://www.ti.com/lit/zip/sluc506

I hope this is helpful.

Ray