Hi all,
can anybody please tell me how to calculate the maximum achievable output current of a switcher in inverting buck-boost topology?
According to several application notes like e.g. slva317b, the maximum output current depends on the Vin to Vout ratio and the current the switcher and inductor can handle.
and
Switcher efficiency is not considered in these application notes.
In some other application notes, e.g. SNVA807, the efficiency is incorporated in the formula, but I wonder if it is correct.
,
You can see that in case the Vin to Vout ratio is equal to 1/n, your switcher may be able to deliver as much current as you like, your maximum output current is zero.
I am a bit confused about this.
Think of a 100A Switcher with an efficiency of 75% that shall convert +5V to -15V. According to SNVA807, the maximum output voltage is zero, simply nothing, not a single milli-amp.
Can anbody please explain to me of SNVA807 is correct?
And why it is correct?
Regards, Niels