PMP41031: T1 connection(schematic)

Yasushi Fujiwara

Part Number: PMP41031

Hello Experts,

My customer has question as follows. Would you answer it, please?
[Question]
This is a question regarding the evaluation board circuit diagram provided by your company. Project title [1500V HV AUX Power] Attached is the circuit diagram. Is the pulse transformer T1 for driving Q1 connected to the wrong connection? I think the correct wiring for pin 2 of T1 is VDD, but what do you think? The route for T1's excitation current when Q3 is off is not secured. If I had to say it, it would be T1-3→T1-7→D6→D4→R7//R41→T1-6, but I think that is different from the purpose of D6.

[PMP41031 schematic]
file:///C:/Users/a0385644/Downloads/TIDMBZ3.PDF

Best Regards,
Fujiwara

6 months ago

0 Sheng-yang Yu1 6 months ago

TI__Expert 4120 points

Fujiwara san,

I have forward this thread to the designer - Max Wang, who is on National holidays right now. He should gets back to you early next week.

Regards,

Sheng-Yang Yu

0 Max Wang1 6 months ago

TI__Intellectual 1580 points

Hi Fujiwara,

thanks for reaching out, the reset of driver transformer will go through D5/D7 plus VDD voltage to make sure it was sufficiently reset for each switching cycle.

Max

0 Yasuhiro Ishikawa 6 months ago in reply to Max Wang1

Prodigy 30 points

When Q3 is off, Excitation current is T1-3→D5→D7→VDD →VDD_capacitor→com(▽mark)→×(There is no place to go).

The important point is that there is no route back to T1-2.

Actually, T1 is reset by the route T1-7→D6→D4→R41//R7→T1-6.

In other words, D5 and D7 should have no meaning.

D5 and D7 may damage other elements.

0 Max Wang1 6 months ago in reply to Yasuhiro Ishikawa

TI__Intellectual 1580 points

I made some simulation, it can go through Q4 to reset, or it can be reset through D6 in secondary side depend on which will act first.

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PMP41031: T1 connection(schematic)