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Datasheet of DSP56F803EVM - KIT EVALUATION FOR DSP56F803
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DSP56F803EVM User Manual, Rev. 5
2-16
Freescale Semiconductor
2.15 Back-EMF and Motor Phase Current Sensing
The UNI-3 connector supplies Back-EMF and Motor Phase Current signals from the three
phases of a motor attached to a motor drive unit. The Back-EMF signals on the UNI-3
connectors are derived from a resistor divider network contained in the motor drive unit.
These resistors divide down the attached motor’s Back-EMF voltages to a 0 to +3.3V
level. In certain instances, the Back-EMF signals can exceed this maximum range. The
Motor Phase Current signals are derived from current sense resistors. Both of these signal
groups are then routed to a group of header pins that allow the end user to select which
signal group the device’s A/D will monitor. Refer to
Figure 2-12
for the design of a single
channel.
Figure 2-12. Primary Back-EMF or Motor Phase Current Sense Signals
BACK_EMF_A
PHASE_A_I_SENSE
AN2
JG6
2
3
1
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