Other Parts Discussed in Thread: UCC21520, TIDA-00199
According to the schematic of TIDA-00366, at the starting point it's clear that bootstrap capacitors aren't charged.
So AMC1301 IC's used for three-phase current sensing are not supplied because their VDD1 are supplied from bootstrap circuit (VCC_U,VCC_V,VCC_W).
It is noted in AMC1301 datasheet that when VDD1 supply is missed, there is a fail-safe output strategy that Vout-p goes to about zero and Vout-n about 2.7v. The Amc output is Amplified with a gain of 0.797 through OPA320 and is summed with 1.65V which is (2.7*0.797+1.65=3.8v). so OPA output is saturated in 3V3.
Finally, Disable signal turns off the ucc21520. So bootstrap circuit cannot be charged at all.
Am I right? this is what I am experiencing in my circuit. Is there any solution?