78M6631-IM/F MAXIM [Maxim Integrated Products], 78M6631-IM/F Datasheet - Page 8

• Manufacturer Part Number: 78M6631-IM/F
• Description: 3-Phase Power-Measurement IC
• Manufacturer: MAXIM [Maxim Integrated Products]

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•
1.4
The AFE functions as a data acquisition system, controlled by the MPU. The main blocks in the AFE
consist of an input multiplexer, a delta-sigma A/D converter, a FIR decimation filter and a voltage
reference. The metrology input signals (IAP, IAN, IBP, IBN, ICP, ICN, VA, VB, VC, and TEMP) are
multiplexed before being sampled by the ADC. The ADC output is decimated by the FIR filter and the
results are stored in RAM where they can be accessed by the CE and the MPU.
The functionality of the AFE is established for various system requirements with different CE code. AFE
programmability includes, but is not limited to:
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1.4.1 Analog Current and Voltage Inputs
With all CE code implementations for the 78M6631, pins IAP, IAN, IBP, IBN, ICP, ICN, VA, VB, and VC
are analog inputs to the AFE for measuring current and voltage. Various current sensor technologies can
be supported including Current Transformers, Resistive Shunts, and Rogowski coils.
8
Input multiplexer settings
Voltage supply and temperature monitor inputs
ADC sampling rate
FIR length/resolution
Analog Front-End (AFE)
ICN
IAP
IAN
IBP
IBN
ICP
VA
VC
VB
V3P3D
TEMP
+
+
+
-
-
-
CTRL
MUX
MUX
MUX
Figure 2: AFE Block Diagram
CROSS
CK32
VBIAS
VREF
VREF
FIR_DONE
FIR_START
V3P3A
VBIAS
+
VREF
-
CONVERTER
4.9152 MHz
∆Σ ADC
FIR
Rev 1