STSPIN32F0,Vreg12(Pin6) cannot output DC voltage stably.

[Dylan.Dong]

Problem Description.

After reflow soldering the circuit board, after visual inspection to exclude the problem of soldering quality, the power test on the tooling (DC 12V power supply, the output of the circuit board is not connected to the load). Output waveform is not normal, about 20%. Further test found that Vreg12 (Pin6) could not output DC voltage stably, and the phenomenon did not improve after adjusting the power supply voltage to 13V, meanwhile, the high level of HSU (PIN32), HSV (PIN29) and HSW (PIN25) output signals could not all bootstrap to 24V.

[Cristiana SCARAMEL]

Hello @Dylan.Dong​,

are you using our evaluation board or a custom one?

In the second case, please share the schematic, in particular your power supply strategy.

If you use a VM voltage equal to 12 V, the VM pin and the linear regulator output can be

shorted together providing the gate driver supply externally.

Refer to the Recommended operating conditions in the STSPIN32F0 datasheet (Table 3 at page 8).

Let me know more details for a better support.

[Dylan.Dong]

Hello Cristiana SCARAMEL,

I am using a similar STEVAL-SPIN3201 evaluation board schematic please refer to STEVAL-SPIN3201.

[Cristiana SCARAMEL]

Hi @Dylan.Dong​ 

have you check the power supply configuration?

As already written above, if you use VM = 12 V you must short VM and VREG pins (JP1 closed in the STEVAL-SPIN3201 board).

[Dylan.Dong]

I have checked that the power supply configuration is good, but the test results still do not work.

[Cristiana SCARAMEL]

Could you show us the VREG12 and VM waveforms in the same screenshot?

If you do not share any application details (e.g. schematic) I don’t know how I can help you.

[Dylan.Dong]

OK, I will test it and send it to you as soon as possible.

[Dylan.Dong]

This is the waveform of VREG12 and VM.

[Cristiana SCARAMEL]

Hi @Dylan.Dong​,

from the VREG12 waveform it seems that the internal current limiter is operating.

You have to check in you schematic, what can be the root cause.

[Dylan.Dong]

Okay, thank you for your enthusiastic help.