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Where can I find HW deadtime setting?

DMeie.2
Senior II

We're using a driver that inserts a deadtime by hardware.

It is not clear to me how I have to configure that into the MCWB firmware to get ADC measurement working properly.
I see three deadtime-related settings:
- "minDeadTime" property in the "PhaseVoltageGeneration" feature of the Motor Control Boards Description
- "deadTime" property of the "DrivingHighAndLowSides" HW variant (this reads like this is a fixed deadtime inserted by the PWM timers)
- "SW dead-time" setting in the FOC wizard

I couldn't find a proper documentation for any of those.

What do these values do?
Which of those settings is the correct one for my case?

3 REPLIES 3
GMA
ST Employee

Hello @DMeie.2,

Two definitions are present: "minDeadTime" and "deadTime" and come from power board or inverter json files.
Usage depends on the following hardware variant (please refer to our Motor Control Boards Description page:(

  • Driving high and low sides power switches hardware variant.
    In this use case, you are able to drive the High and Low PWM signals and then handled by SW. SW_DEADTIME_NS is used. "minDeadTime" is used as a low-level limit for SW_DEADTIME_NS definition.
  • Driving high sides and one enable hardware variant. 
    In this use case, you are able to drive the High PWM signals with a Enable signal. In this case, Dead Time only depends on HW. HW_DEAD_TIME_NS is used and is defined as "deadTime" value.
If you agree with the answer, please accept it by clicking on 'Accept as solution'.
Best regards.
GMA
DMeie.2
Senior II

@GMA 

We're using variant 1 and drive both high- and lowside.
The driver stage then inserts a configurable deadtime in hardware.

I'd like to account for this inserted deadtime in the ADC current measurement so that it only starts sampling after the external deadtime has elapsed.

Do I have to use those deadtime settings for that? Or do I rather have to use the tNoise/tRise settings for that?
Deadtime is mentioned in the "Current sampling in three-shunt topology using one A/D converter" document, though I'm not sure which one that is supposed to be.

GMA
ST Employee

Hello @DMeie.2,

If "We're using variant 1 and drive both high- and lowside.", dead time is then managed by software.

 

GMA_0-1736411116337.png

 

If you agree with the answer, please accept it by clicking on 'Accept as solution'.
Best regards.
GMA