PM4100APD South African Micro-Electronic Systems, PM4100APD Datasheet - Page 3

• Manufacturer Part Number: PM4100APD
• Description: PM4100APD Evaluation Module is Designed to Demonstrate The Functionality of The Sames SA2002E, SA2002H, SA2002P, SA2002D And SA2102D Integrated Circuits.
• Manufacturer: South African Micro-Electronic Systems

CURRENT SENSE INPUT
Resistors R2 and R3 (figure 3 and figure 4) define the current
level into the current sense inputs of the device. The
PM4100APD module can be configured to use any type of
shunt or CT, but to ensure proper current sensing it is advisable
to use a shunt or CT that will give a voltage drop of at least 20mV
at maximum supply current. The resistor values are calculated
for an input of 16µA
conditions. The design equation is as follows:
R2 = R3 = (I / 16µA) x R
I
R
SENSING METHOD (CT OR SHUNT)
Provision is made for the use of either a Current Transformer
(CT) or a Shunt on the application module. For use with a CT,
the terminating resistor (R1) and phase compensation
capacitor (C1), as well as jumper (J1) must be inserted. The
jumper references one side of the CT to ground for sensing.
When using a CT the current sensing resistors (R2 and R3)
must be inserted according to the equation stated below.
R2 = R3 = (I /2500/16µA) x R
I
1:2500 = CT ratio
http://www.sames.co.za
L
CON2
CURRENT
CON2
CURRENT
L
PM4100APD
SH
= Line current
= Line current
= Shunt value
3
2
1
3
2
1
Figure 3: Current sensing using a shunt
L
L
Figure 4: Current sensing using a CT
GND
GND
RMS
SH
on the current sense inputs at rated
/ 2 SHUNT Sensing
1
/2
R1
J1
CT
CT Sensing
R2
R3
R2
R3
IIN
IIP
IIN
IIP
3/14
The capacitor C1 is inserted to compensate for the phase shift
caused by the current transformer. The following equation
shows how to calculate the capacitor value for a phase shift of
0.18 degrees.
C = 1 / (2 x x Mains frequency x R8 x tan(Phase shift angle))
C = 1 / (2 x x 50 x 1M x tan(0.18 degrees))
C = 1.013µF
CTs with a low phase is recommended.
REFERENCE VOLTAGE
The on chip reference current is determined from a biasing
resistor R4 connected between pin 3 of the device and V
This is 47k for the SA2102D and SA4102A, and 24k for the
rest of the devices compatible with this module.
ANALOG GROUND (GND)
The GND pin of the device is connected to the analog ground
plane, which is halfway between V
DD
and V
SS
.
sames
sames
SS
.