NXP Semiconductors MC56F80000-EVKUM, Руководство пользователя, Страница: 19 / 26

NXP Semiconductors
MC56F80000-EVKUM
MC56F80000-EVK Board User Manual
R 129
C
84
GB 0 _IN
GB 0
Figure 16. Equivalent circuit for phase B current sensing — with external OPAMP
• With DSC internal OPAMP
In phase A current sensing circuit, when the DSC internal OPAMP is used for current
sensing, the jumpers configuration is described as follows.
The pin 2 and pin 3 of J24 are connected, and J20 and J23 are both connected. The
equivalent circuit is shown in Figure 17 . In this condition, GA0_IN and GA1_OPA_P
are signals at both sides of the shunt resistor, and ADC_MID is a bias voltage, which
makes sure the output of the OPAMP is a positive value and the typical value is 1.65 V.
GA0_IN is connected with GPIOA0 (OPAMPA_IN3) through R123, GPIOA0
(OPAMPA_IN3) is configured as inverting input of the OPAMPA. GA1_OPA_P
and ADC_MID are connected with GPIOA1 (OPAMPA_IN0) through R116 and
R113, respectively. GPIOA1 (OPAMPA_IN0) is configured as non-inverting input
of the OPAMPA. The R122 is between GPIOA0 (OPAMPA_IN3) and GPIOC4
(OPAMPA_OUT), and GPIOC4 (OPAMPA_OUT) is used as output of the OPAMPA.
Therefore, R122 is a negative feedback resistor. The signal of the GPIOC4
(OPAMPA_OUT) is the phase A current sensing signal.
The OPAMPA output signal OPA_OUT on GPIOC4 can be connected with ANA7
directly within DSC though ADC register configuration. RC filter can also be added
between the OPAMP and the ADC input when R138 and R140 are soldered, which is
not populated by default. In this case, the filtered OPAMP output signal is connected
with GPIOA4 (ANA4). If a 0 Ω resistor is soldered at the R138 position, and R140 is
DNP, C89 is connected with the OPAMPA output directly, which can reduce the noise
too.
OPAMP OPAMP
R 123
R 122
GC
4
GA
1 OPA_OUT
-
+
v-
v+
GA
1
_OPA_P
ADC_MID
GA
0
_IN
R 116
R 113
GA
0
R 138
DNP
C
89
R 140
GA 4
DNP
C 77
C 79
OPAMP
R 123
R 122
GC
4
GA
1 OPA_OUT
-
+
v-
v+
GA
1
_OPA_P
ADC_MID
GA
0
_IN
R 116
R 113
GA
0
R 138
DNP
C
89
R 140
GA 4
DNP
C 77
C 79
Figure 17. Equivalent circuit for phase A current sensing — with DSC internal OPAMP
The circuit designed for phase B current sensing is similar as phase A current sensing
circuit, connect pin 2 and pin 3 of J25, and the equivalent circuit is shown in Figure 18 .
OPAMP OPAMP
R
128
R 127
GF 0
GB 1 OPA_OUT
-
+
v-
v+
GB 1 _OPB_P
ADC_MID
GB 0 _IN
R 117
R
114
GB 0
R 139
DNP
C 90
R 141
GB 4
DNP
C 78
C 83
OPAMP
R
128
R 127
GF 0
GB 1 OPA_OUT
-
+
v-
v+
GB 1 _OPB_P
ADC_MID
GB 0 _IN
R 117
R
114
GB 0
R 139
DNP
C 90
R 141
GB 4
DNP
C 78
C 83
Figure 18. Equivalent circuit for phase B current sensing — with DSC internal OPAMP
2.8 OpenSDA
OpenSDA is a serial and debug adapter circuit. It bridges serial and debug
communications between the USB host and the target processor MC56F80748.
MC56F80000-EVKUM All information provided in this document is subject to legal disclaimers. © 2022 NXP B.V. All rights reserved.
User manual Rev. 1 — 14 December 2022
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