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TMC4670 Datasheet PRELIMINARY • IC Version V0.99 | Document Revision V0.91 • 2016-Nov-09
The job of the ADC scaler is to map raw ADC values to the 16 bit signed (s16)
range and to center the values to zero by removing of offsets.
Info
Figure 7: ADC Selector & Scaler w/ Offset Correction
ADC offsets and ADC scalers for the analog current measurement input channels need to be programmed
into the associated registers. Each ADC_I_U, ADC_I_V, ADC_I_UX, ADC_I_WY, ADCSD_I_UX, ADCSD_I_WY,
ADC_I0_EXT, ADC_I1_EXT is mapped either to ADC_I0_RAW or to ADC_I1_RAW by ADC_I0_SELECT and
ADC_I1_SELECT.
In addition, the ADC_OFFSET is for conversion of unsigned ADC values into signed ADC values as required
for the FOC.
ADC_I0 = (ADC_I0_RAW + ADC_I0_OFFSET) · ADC_I0_SCALE
ADC_I1 = (ADC_I1_RAW + ADC_I1_OFFSET) · ADC_I1_SCALE
(3)
(4)
For FOC3 the third current ADC_I2 is calculated via Kirchhoff’s Law. This requires the correct scaling and
offset correction before. For FOC2 there is no calculation of a third current.
The ADC_UX_SELECT selects one of the three ADC channels ADC_I0 ADC_I1, ADC_I2 for ADC_UX.
The ADC_V_SELECT selects one of the three ADC channels ADC_I0 ADC_I1, ADC_I2 for ADC_V.
The ADC_WY_SELECT selects one of the three ADC channels ADC_I0 ADC_I1, ADC_I2 for ADC_WY.
The For FOC3 the third current ADC_I2 is calculated via Kirchhoff’s Law. This requires the correct scaling
and offset correction before. For FOC2 there is no calculation of a third current.
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