How to account for the low voltage when designing a Step Down Switching Regulator Design procedure:   **Essentially my question is say I have an input voltage that can range from 7-15V. When designing this converter (must use this converter), so I only do calculations based upon the maximum input voltage. Say the output voltage was 2 V

If it is 7 V input wouldn't a new inductor value have to be chosen as it would have a different value? Or do we just have to use the value chosen for the maximum input voltage? I.e. the lower the input voltage wouldn't the higher the inductor value L1 have to be from the equation in the second table?**

Thus how do you account for this voltage range? Do I just use the max input voltage only for calculations?

Is this just a tradeoff that has to happen or do I calculate for both ranges and see what the current ripple is? Also for the capacitor, different input voltages will cause the capacitance value to change as seen in the Cout equation. Hence to I do a design for both and see what the ripples are for each component value and say possibly the 7V input voltage value found for L1 is better than than the 15 V?

• Having too high an inductance won't generally stop a buck converter from working; indeed, it will generally work better (though with a slightly slower startup time). So use an inductance higher than the highest inductance needed by any voltage in your range (and do keep in mind that you want to stay below the inductor's saturation current) – Hearth May 9 at 3:10
• ooh that data sheet is a mess, all the circuit schematics have the wrong pin numbers – Jasen May 9 at 7:28