INTVCC_UVLO value of LT8645S

Hi kshigemori281,

INTVCC UVLO is an input to the OR gate for the PG pin but this signal can't be controlled. What is the reason this is important in your application? INTVCC is the output for the internal 3.4V regulator and this pin should not be loaded with external circuitry.

Hi,

I have trouble Both LT8620 and LT8645S. I also confirmed similar problem.
First of all , I confirmed INTVCC waveform of LT8620 that reached UVLO when It's reverse voltage.
Second of all, I confirmed value of INTVCC UVLO with datasheet of LT8620. Therefor I confirmed value of LT8645S. However I couldn't confirm this.

Best regards

Can you provide more information about the issue? Could you clarify how is the INTVCC related to the reverse voltage you're seeing?

Hi,

Thank you your quick reply.
I confirmed that INTVCC voltage decrease and reach threshold of INTVCC UVLO during reverse voltage. I also confirmed INTVCC is return after UVLO. However It is continue several time.

Since a large current flows through the body diode of the internal FET during the reverse voltage, it is thought that the cause is insufficient capacity to supply the FET driver from CVCC.

It isn't frequently happen this reverse voltage. For example, blackout and Hotswap.
I am considering this issue is occured as accumulated damage.

Best regards

Hi,

Thank you your quick reply.
I confirmed that INTVCC voltage decrease and reach threshold of INTVCC UVLO during reverse voltage. I also confirmed INTVCC is return after UVLO. However It is continue several time.

Since a large current flows through the body diode of the internal FET during the reverse voltage, it is thought that the cause is insufficient capacity to supply the FET driver from CVCC.

It isn't frequently happen this reverse voltage. For example, blackout and Hotswap.
I am considering this issue is occured as accumulated damage.

Best regards

Hi,

Have you tried doing the circuit in Figure 6 of the datasheet? This may help in your reverse voltage issue.

Hi,

Thank you for your reply.

I have done put on diode between Vin and Vout. Is this measures effective?

Is Figure 6 more recommend than above measures.

Best Regards