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LM25116: Selection of IC for Peak current mode control in synchronous buck converter

Prem Ankitkumar Shah
Prodigy 140 points
Part Number: LM25116
Other Parts Discussed in Thread: TMS320F28027, , LM5116, LM5170, LM25149, LM25141

Hi, 

I am planning to implement a synchronous buck converter which is having two loop control: Outer Voltage loop and inner peak current control loop. I am hoping to implement the outer voltage loop digitally using TMS320F28027 microcontroller, However, I plan to select an analog IC to have an accurate and continuous time control using peak current mode control techqniue. 

So, here's my question : 
My application is step down from 12V to 5V, 15W sync buck converter. I was considering LM25116/LM5116 for the application, However I am not sure if it is possible for me to do compensation digitally and use an Analog chip which takes the output of Voltage loop (Vc) as an input and generates switching signals for high-side and low-side N-Chanel Power Mosfet. Can you please suggest any product which does this or how this would be possible with LM25116/5116? 

PS: Control Block Diagram is attached herewith: 

Thanks,
Prem Shah.

  • 0
    TI__Guru 73752 points

    Hi Prem,

    Take a look at the LM5170 with average current-mode loop. Alternatively, the LM25149 and LM25141 are peak current-mode controllers with a gm voltage loop error amp that can be overdriven externally if needed. The LM25116 has an op-amp type error amp and is less suitable for that purpose.

    Regards,

    Tim