SMPS transfer function - open-loop or closed-loop?

[eem2am]

smps transfer function

Hello,

With a switch mode power supply, we can add the transfer function of the modulator to the transfer function of the error amplifier………….but the result of this addition………..please can you tell me what it is called….is it the “open-loop” transfer function or the “closed-loop” transfer function ?

 

[FvM]

SMPS transfer function

The transfer functions are multiplied rather than "added". This applies basically to the open loop function. And I wouldn't say "can", cause you don't get a correct open loop transfer function ignoring the modulator.

For a closed loop transfer function, you have to define in- and output first. You may e.g. define the load voltage as output and the setpoint as input. But in case of a constant setpoint, this closed loop transfer function wouldn't be really meaningul, I think.