STSPIN32F0 Overcurrent detection R43 value

[TYama.17]

According to the reference circuit, R43 is 75kohm.

Also UM2154 User manual said that R43 should be higher than 30kohm.

What happens if R43 is 22kohm. Is overcurrent detected by STSPIN32F0?

[Cristiana SCARAMEL]

Hello @TYama.17​ and welcome to the ST Community.

The first effect of lower R43 is an higher current consumption from VDD.

Moreover, it is recommended to use a bias resistor (R43) more than 10 times greater of the resistors on the sensing lines (R50, R51, R52).

You can find more details on the proper sizing of overcurrent protection in the application note AN4999

Let me know if these info are useful to you, if yes please "Select as Best" label to close the topic.

[TYama.17]

Cristiana san

Thank you for you comments,

By the way, what is STSPINF0 behaiver when overcurrent occurs?

[Cristiana SCARAMEL]

Hi @TYama.17​ ,

When an overcurrent event is triggered, the OC comparator output signals the OC event to the PB12 input of the MCU (BKIN).

Depending on the status of the OC_SEL signal the OC event is acting directly on the control logic of the gate driver switching off all high-side gate outputs, or not.

You can find all the details of overcurrent protection in the STSPIN32F0 datasheet (paragraph 6.9).

[TYama.17]

In addition, I tried to measure the voltage of C21 (GND-OC Comp) by osiloscope, but I could not because STSPINF0 seemed not to work.

Could you teach me how to measure this voltage?

Also could you give me suitable capacitor value for C21. (is 2.2uF suitable?)

[Cristiana SCARAMEL]

Hi @TYama.17​,

the value of C21 capacitor in the STEVAL-SPIN3201 evaluation board is 1 nF as shown in the schematic of your first post.

If you want to change its value the details on the proper sizing are always on the above mentioned application note AN4999

<< STSPINF0 seemed not to work >> is a very generic feedback.

If I understand well you are using our STEVAL-SPIN3201 evaluation board, right?

Did you follow the "Getting Started" steps of user manual UM2154?

Could you share more details on your application? Are you using a custom firmware?

The board is designed for sensored (encoder or digital Hall sensors) or sensorless vector control - FOC algorithms with 3-shunt sensing.

Which one did you choose?

I suggest to follow the UM guidelines and possibly come back with more specific questions.

[TYama.17]

Hi Cristiana san

My schematics is as follow. Unfortunataly I am not familiered with algorithms.

I tried to measure the voltage of OC_Comp on C668_1(2.2uF) capacitor by osilloscope, but I could not see 3.3V from STSPIN32F0. (I did not measure the 9-pin signal).

Is this information specific for you?

[Cristiana SCARAMEL]

Hello @TYama.17​,

a portion of schematic is not enough for a better support.

I suggest you to check if all the supply voltages are present and if the devices is properly programmed (the  STSPIN32F0 must be programmed to work).

[TYama.17]

Hi Cristiana

I finally measured the voltage of OC_COMP pin between V_MOTOR_GND1 and OC_Comp pin. I was very noisy, I guess GNDing is not suitable on my board...

[x4ce]

Hi,

Can you please share this reference circuit shown in your original circuit as I am not able to find it.

Anyone else please also share if possible.

 

Thanks