Datasheet

TMC4671 Datasheet • IC Version V1.00 | Document Revision V1.03 • 2018-Sept-06

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Vmin[V] Vref[V] Vmax[V] VIN[V] DUTY[%] ADC_RAW

0.0 1.65 3.3 0.0 0% 0x0000

0.0 1.65 3.3 0.825 25% 0x4000

0.0 1.65 3.3 1.65 50% 0x7ﬀf

0.0 1.65 3.3 2.475 75% 0xC000

0.0 1.65 3.3 3.3 100% 0xﬀﬀ

Vmin[V] Vref[V] Vmax[V] VIN[V] DUTY[%] ADC_RAW

0.0 2.5 5.0 0.0 0% 0x0000

0.0 2.5 5.0 1.0 25% 0x4000

0.0 2.5 5.0 2.5 50% 0x7ﬀf

0.0 2.5 5.0 3.75 75% 0xC000

0.0 2.5 5.0 5.0 100% 0xﬀﬀ

Table 14: Delta Sigma input voltage mapping of external comparator (CMP)

4.6 Analog Signal Conditioning

The range of measured coil currents, resp. the measured voltages of sense resistors, needs to be mapped

to the valid input voltage range of the delta sigma ADC inputs. This analog preprocessing is the task of the

analog signal conditioning.

4.6.0.1 Chain of Gains for ADC Raw Values

An ADC raw value is a result of a chain of gains that determine it. A coil current I_SENSE ﬂowing through a

sense resistor causes a voltage diﬀerence according to Ohm’s law. Finally, a current is mapped to an ADC

raw value

ADC_RAW = (I_SENSE ∗ ADC_GAIN) + ADC_OFFSET. (11)

The ADC_GAIN is a result of a chain of gains with individual signs. The sign of the ADC_GAIN is positive

or negative, depending on the association of connections between sense ampliﬁer inputs and the sense

resistor terminals. The ADC_OFFSET is the result of electrical oﬀsets of the phase current measurement

signal path. For the TMC4671, the maximum ADC_RAW value is ADC_RAW_MAX = (2

−

1) and the minimum

ADC raw value is ADC_RAW_MIN = 0.

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