Hi TI support
Strange behaviour hoping to get some support with. We've cascaded two TPS63020 to avoid single fault condition with a shorted input regulator. VSwitched input is 3.8V and VSYS output of stage 1 regulator is 2.77V. This is fed directly into a second regulator which is supposed to have a 2.8V output.
When in this configuration, the Vsys = 2.77V as expected, however 2V8 is significantly under voltage (approx 2.4V).
If we bypass the first regulator and apply 2.7V to VSys through a regulated power supply, the secondary regulator behaves appropriately and 2V8 = 2.8V.
So, in short, individually they are fine, cascaded they seem to misbehave - we've worked up multiple boards with this same issue and hoping to get some clarity on what we're doing wrong?!
Screenshots of the corresponding schematic - apologies for the scale & symbol difference, they're on different sheets in our design.