NXP Semiconductors
MC56F80000-EVKUM
MC56F80000-EVK Board User Manual
2.7 OPAMP test circuit
The OPAMP test circuit is designed to use the DSC internal OPAMPs together with the
phase current sensing circuit of motor power stage board (
). The
FRDM-MC-LVPMSM board is connected with the EVK board through Arduino interface.
You can select to use the external OPAMPs on FRDM-MC-LVPMSM or DSC internal
OPAMPs for current sensing by configuring the jumpers.
The following figure shows the schematic diagram of the OPAMP test circuit.
OPB_N
OPA_P
OPAMP t e s t w it h m o t o r co n t ro l
b o a rd fo r CUR_ A & CUR_ B
ADC_MID
ADC_MID
GA1_OPA_P
GB1_OPB_P
GA0_IN
GB0_IN
R141
0
DNP
R122
10K
R140
0
DNP
R117
1.0K
J 23
HDR 1X2
1
2
J 20
HDR 1X2
1
2
J 25
HDR_1X3
J UMP ER DEFAULT = 1-2
1
2
3
R116
1.0K
R129
100
R128
1.0K
R123
1.0K
R127
10K
R138
100
DNP
R113
10K
C84
220 pF
C79 150 pF
C78
150 pF
R114
10K
TP 19
R139
100
DNP
R125
100
C89
220 pF
R118
0
C77
150 pF
C83 150 pF
C90
220 pF
C82
220 pF
J 24
HDR_1X3
J UMP ER DEFAULT = 1-2
1
2
3
GA0
GB0
GC4
GA1
GB1
GF0
GA4
GB4
OPB_P
OPA_OUT
OPB_OUT
OPA_N
CUR_A
CUR_B
Figure 14. OPAMP test circuit schematic
• With external OPAMP (default)
In phase A current sensing circuit, when the external OPAMP on
is used for current sensing, the jumpers configuration is described as follows. The pin 1
and pin 2 of J24 are connected, and J20 and J23 are both unconnected.
The sensing signal from the output of the external OPAMP is connected with GPIOA0
(ANA0) through an RC filter. The following figure shows the equivalent circuit.
R
125
C
82
GA
0
_IN
GA
0
Figure 15. Equivalent circuit for phase A current sensing — with external OPAMP
For phase B current sensing, connect pin 1 and pin 2 of J25. Sensed phase B current
signal is connected to GPIOB0 (ANB0) through an RC filter.
shows the
equivalent circuit.
MC56F80000-EVKUM
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User manual
Rev. 1 — 14 December 2022
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