User Manual
26 of 47
Revision 1.4
2020-07-16
EVAL-M3-IM564 User Manual
iMOTION
™
Modular Application Design Kit
Hardware description of EVAL-M3-IM564
4.2.2
Motor external current feedback configuration and calculation
The current input value is a product of the shunt resistance in milliohms and gain of external current sense
amplifier for EVAL-M3-102T, as shown in Figure 21.
Figure 21 Current shunt feedback and sample timing for EVAL-M3-102T
The external amplifier gain circuit can be found in the schematics or user manual for the control board (for
example, EVAL-M3-102T see Figure 22).
Figure 22 depicts IU+ current feedback sensing circuity on the EVAL-M3-102T evaluation board. Please note that
the default external gain is 5/6 for the EVAL-M3-102T control board. However, since the EVAL-M3-IM564 power
board has been configured with an external op-amp with a gain of 10, the following modifications to the circuit
of the EVAL-M3-102T control board are recommended for more accurate gain calculations.The resistor R10 on
the EVAL-M3-102T needs to be removed and R13 needs to be change to 0 ohm.
Figure 22 The part of current feedback on the EVAL-M3-102T evaluation board
R12
100ohm 1/10W 1%
R13
2Kohm 1/10W 1%
R10
10Kohm 1/10W 1%
C21
220pF
+3.3V
IU+
Rsh
Ish
iMOTION
Controller
IU
18
V1
V2
Current shunt resistor
on power board
R13 change to 0 ohm
Delete R10
EVAL-M3-IM564
EVAL-M3-102T