LM5023: OVP detection timing

Hi Shimizu, see answers below.

Q1: Does "Tovp (Sample delay for OVP)" mean blanking time? - Yes

Q2: During how long time does LM5023 detect OVP?  for all toff? - The OVP comparator pin is sampled TOVP after the MosFET turn off.

Thanks

Billy

Shimizu, appologies for the delay replying, I wasn't getting notifications of your post so didn't realise you had follow on questions.

I'm not sure how long the detection period is, but you can see from the block diagram in section 7.2 of the datasheet that the Gate Drive turn off is delayed and used to trigger a flip flop which will disable the IC if the OVP comparator is high.

The trigger pulse is likely to be short, therefore you can regard the operation as a point sample at T = Tovp after turn off.

The voltage on the output cap will not change much on a cycle by cycle basis, so if the output voltage is too high it will be too high for the entire sample. The main thing to be careful of is that you do not sample the leakage inductance ringing, which is the reason for the delay before taking the sample.

The output voltage should not increase noticably during the rest of the flyback interval.

Thanks

Billy