Part Number:TPS40428
Hi TI,
We used two TPS40428 for 5VA and 5VB VR solution and this design required redundant feature so we also added two TPS2412 for oring control but no active current sharing circuitry there due to PCB space limitation.
Then we found the Oring gate of P5VA keeps low state at no load or light load condition due to bad current sharing, only P5VB oring enabled.
If we perform the internal short at P5VB rail, the P5V (after OringFET) will drop to about 4.3V (5V-oringFET Vf) because the P5VA oring gate needs about 3~6ms ramping time to to enable the OringFET.
We think the root cause is no active current sharing circuitry to adjust two VR output has very close output voltage.
We read from datasheet and know TPS40428 could be set as 4-ph configuration so we want to ask is it possible to set two independent TPS40428 to achieve current sharing balance?
Like 2ph + 2ph with independent Vout feedback and tie four ISH signals together. If it cannot be set as that way, is there any recommended solution for our case?
BR.
Stan.