Typical Sensor Connections; Figure 6. Shunt Sensor Power Meter - Cirrus Logic CDB5490U Manual

1.6

Typical Sensor Connections

The CDB5490U evaluation board provides connections directly to several types of sensors. Flexible on-
board filter networks provide a convenient configuration for three common transducers: current shunt, cur-
rent transformer (CT), or Rogowski coil.
1.6.1 Shunt Power Meter Example
An inexpensive current shunt configuration is easily achievable with the CDB5490U evaluation board.
Figure 6 depicts the voltage and current connections for a shunt sensor and its associated filter configu-
rations.
It is strongly recommended that a low-side (neutral path) current shunt is used — especially in high-volt-
age situations. Make sure that all signals are well connected before the power source is turned on. Ex-
treme care should be taken when connecting high-voltage signals to the CDB5490U evaluation board.
In this configuration it is unnecessary to use a burden resistor. A single anti-alias filter is all that is required
for the current channel. Below the filter corner frequency, the CS5490 inputs will see the same voltage
that is across the shunt. Therefore the shunt voltage should be kept below the maximum of 50mVp with
I-Channel PGA = 50x. A 10% margin is recommended for the shunt voltage (45mVp).
GND
IIN+
SHUNT
IIN-
GND
LINE
GND
12
CDB5490U
J1
NO POP
R11
J4

Figure 6. Shunt Sensor Power Meter

J46
J8
R2
100
NO POP
R13
J7
NO POP
R9
100
R1
J44
J6
J45
R5
1K
J11
CDB5490U
R50 1K
0.033UF 0.033UF
J54
C6 C35
0.033UF 0.033UF
J53
C5 C34
R49 1K
0.027UF
C4
0.027UF
C9
DS923DB5
IIN+
IIN-
VIN+
VIN-