Figure 10. 3-phase output stage
3.7 Current Sense
A set of four different resistors are provided on the board for current sensing in different applications. There is one current
sense resistor for each phase (R48, R56, R68), plus one resistor to sense the DC bus current (R71). The components
populated on the board are 10 milliohm, 1% tolerance resistors. Several different options are provided on the board to enable
current sense on multiple resistors at the same time. The MCU integrates two current sense amplifiers, and there are three
additional amplifiers provided on board using external op-amps.
The two current sense amplifiers integrated into the MCU are mapped each to a different ADC module, to allow for
simultaneous conversions.
Option 1) Internal Op-Amp 0:
The internal current sense amplifier 0 is mapped to the ADC pins at PAD0, PAD1, and PAD2, with the following
configuration:
PAD0 = AMP0, the operational amplifier output.
PAD1 = AMPM0, the operational amplifier inverting input (minus).
PAD2 = AMPP0, the operational amplifier non-inverting input (plus).
Design Considerations
S12ZVM12EVB Evaluation Board User Guide, Rev. 2, 03/2016
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Freescale Semiconductor, Inc.
