Other Parts Discussed in Thread: LM61440, LMS3655, LMR33640, TPS55288, TPS56637, LM61460
The (3 to 17V input, 3A output) TPS62913 is a very interesting Vreg IC. In addition to combining the PSRR of an LDO and the efficiency of a modern switching regulator, all in a small overall footprint, it also offers 100% max duty cycle operation so, e.g., a 5V input can provide a (nearly) 5V output.
Though I can find a couple of controllers (with external switches, generally requiring a much larger overall footprint) that support this function (like the 4.5 to 42V input LM61440), very few other Vreg converters (with integrated switches) that I can find support this function. The closest I can find (in the 3A, up to around 28V input range) are the LM61440 and LMS3635/LMS3655 (~4 to 36V input), which are capable of close to 96% duty cycle, and the (~4 to 36V input) LMR33640, which is capable of close to 98% duty cycle.
In my application, I would like to allow a large (5-28V) input source, and would like to be able to power a 5V motherboard from this source even if a 5V wall wart is plugged in. At this point I am contemplating the use of an optional shunt, to bypass the Vreg altogether if a 5V power supply is chosen. However, this leads to a very substantial possibility for catastrophic error (if someone leaves this shunt inserted, and later plugs in a large (up to 28V) LiPo to the power supply input.
Thus, my question: are there any other TI converters (with integrated switches) that I am missing that offer (close to) 100% max duty cycle and can handle 5V to 28V inputs and 5V (around 3A) output? I have scoured the TI catalog and all WEBENCH results I have generated, and can't seem to find many others. What y'all did with the TPS62913 was, like I said above, very interesting - I'd really love to see a version of that which handles higher input voltages?
