STSPIN958 H-Bridge, current measurement in II and IV quadrant?

[SSCOKM]

We have a prototype board with the STSPIN958 full bridge but we see that it cannot measure positive current (in coil) when the voltage is switched negative, output shows current = 0.

We switch from 48V to -48V on the coil. (turning the magnetic field off fast)

When the current becomes also negative then we have a measurement again.

So we have a blind spot after the voltage polarity on our output changes.

 

Is there a configuration with this IC to keep measuring the current after the voltage polarity switches?

 

Thanks

 

[ADAVE.1]

Hi @SSCOKM 

when polarity is reversed, most of the current is supplied by the diode that is connect to device substrate. This current doesn't flow  through the shunt and cannot be read at the amplifier outputs.

Alessio