I am designing a new system by TPS65090A, unfortunate , the DCDC1 (5V ) and DCDC2 (3.3V) can't work normally.
the output of DCDC1 (5V) is 3.4v and DCDC2 (5V ) is 2.6V when power input is 10V and the outputs can up to to 4.7V and 3.0V when I had enhance the power input to 17V . I had found the switching duty cycles of DCDC1 and DCDC2 don't do any changing when I changed the power input from 8--17V input . also, I had checked the switching frequency is 4.7MHZ which I don't think it is in right way.
though the DCDC3 output (adujstable , switching frequency is 1.5M) and LDOs (5V and 3.3V ) is workable.
So, any expert can help me check that which conditions can caused the result. It seems very strange.
many thanks!
