# How to know when D1 and D2 conduct? [duplicate]

I have trouble solving this DC-DC converter circuit. How do I know when D1 and D2 conduct, when the switches are both on and when only S2 is on?

I've tried solving it with the second law of Kirchhoff, and in both states I got VD1 = Vi - VL1 - Vo. I don't know if this is a positive or negative result, since we don't have voltage values in this task (same thing for VD2).

Is there another, simpler way to solve this without using Kirchhof's second law and common anode/cathode potential? Since in this task we don't have any values, we only know how the switches work.

here is the french text translation : The analysis of this structure will be done in steady state only. All components will be assumed to be perfect. The capacitance C2 is large enough to assume a constant voltage V0. In continuous conduction mode (IL1 (t)> 0), the operating period breaks down into 3 successive sequences. Figure 2 shows the on states (ON) ´ and blocked switches.

• is there another simpler way - use a simulator like the pros. Jan 4 at 16:34
• L.Osmane - Hi, This is just a repeat of your previous question, which you deleted. Therefore I have undeleted that one. It is still waiting for you to kindly add a translation of the French text there. You can (and should) also edit that one to improve it with any new details that you added here. Thanks. (Part of the Stack Exchange "philosophy" is that questions get edited to improve them, not deleted and reposted.) Jan 4 at 16:42