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TPS63900EVM: Higher Quiescent current observed with application circuit

Part Number: TPS63900EVM
Other Parts Discussed in Thread: TPS63900,

I am planning to use TPS63900 in a new product and is currently working o a Proof of concept for the same. The product has a Wireless Bluetooth  transceiver powered from AAA cells x2 through TPS63900EVM.

The average current consumed by the transceiver device is 65uA  but with buck boot in between, I was observing 150uA.

When disconnecting the transceiver ( marked as OTN in above block) the consumption from battery was close to 82uA which is way higher compared to the Iq listed in datasheet.

But later identified that removing C_sup from circuit makes the quiescent current of buck boost down to 0.29uA average.

C_sup is a 470mF Super Cap with 0.4 Ohm ESR connected for an energy harvesting mode of powering. and the two Schottky diodes are supposed to switch voltage sources when available. 

During my experiment, C_sup is not charged from external power stealing and input to that is kept open.

I am not able to figure out why the super cap would consume current from the battery with those Schottky diodes present

This issue is not observed when I use a different make of Buck boost in the path. The quiescent consumption of that circuit is constant with/without Super Capacitor populated.

Any Idea what could be wrong here.

Attaching current consumption waveforms with and without super cap