Cirrus Logic CDB5490U - Manual (Page 12)

CDB5490U
12 DS923DB5
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).
IIN-
IIN+
GND
GND
GND
LINE
CS
5490
CDB5490U
PH
AS
E
NEU
TRA
L
J1
J4
J7
J8
J11
J6
R5
1K
C5
0.033UF
C6
0.033UF
C9
0.027UF
C4
0.027UF
R11
NO POP
R1
100
R2
100
R7 1K
R6 1K
R9
NO POP
R13
NO POP
R8 422K R12 422K R14 422K R15 422K
R49 1K
R50 1K
C34
0.033UF
C35
0.033UF
J44
J46
R51
0
J45
J53
J54
SHUNT
IIN+
IIN-
VIN-
VIN+
Figure 6. Shunt Sensor Power Meter