I have designed a cascaded buck-boost converter also known as non-inverting buck-boost converter which is able to step up or step down the input voltage to produce a range of output voltage of 1V to 12V. But I have an quiry regarding how to prevent the circuit to enter into DCM as I do not wish the inductor current to go beyond zero.
Inductor ΔI is defined by inductance, voltages and switching frequency. For a given switching frequency and input/output voltage, the converter will necessarily enter DCM below a particular load current. So what are you exactly asking for? You didn't mention a minimum load current.
Hi...
For a switching frequency of 50KHZ and input voltage of 5V to produce the output voltage range of 1V to 12V. I have decided to use a load of 100ohm. Is it at output voltage of 1V, the converter will enter DCM?
Assuming CCM, you can calculate the inductor current ripple and switch duty cycles for each input/output voltage combination. The inductor has to been choosen such, that the inductor current stays positive, so CCM is assured.
Basically dI/dt = V/L or ΔI = 1/L ∫Vdt.
Application of the basic equations to DC/DC converter design is performed in chip application notes or text books.
I think, it also helps to sketch the waveforms or perform a simulation of a principle circuit (e.g. using ideal switches and diodes).