current mode control in buck converter

[sumitj]

In current mode control there are two loops one inner loop of current and other one outer voltage loop. Is it necessary to make both loops stable?

If Yes than why it is said that current mode control is easier to stabalize.

Also how one should determine the amplitude of slope compensator.

 

[johnsmith101]

There are two loops:The current loop is fast and the voltage loop is slow. It is only necessary to compensate the voltage loop. It is easier to compensate a current-mode controller because it reduces the order of the system. The amplitude of the slope compensation should theoretically be 1/2 the downward slope of the inductor current. In reality, it tends to be about 0.75-1X the downward slope of the inductor current.

 

[johnsmith101]

Here is a Unitrode appnote that addresses some of your concerns. I apologize for not including it in my previous response.