SA2002 Sames, SA2002 Datasheet - Page 6

• Manufacturer Part Number: SA2002
• Description: Single Phase Bi-directional Power / Energy Metering IC with Instantaneous Pulse Output
• Manufacturer: Sames

ELECTROSTATIC DISCHARGE (ESD)
PROTECTION
The SA2002H integrated circuit's inputs/outputs are protected
against ESD.
POWER CONSUMPTION
The power consumption rating of the SA2002H integrated
circuit is less than 25mW.
INPUT SIGNALS
VREF
A bias resistor of 24k
Calibration of the SA2002H should be done on the voltage
input as described in Typical Applications.
Current sense input (IIP and IIN)
Figure 6 shows the typical connections for the current sensor
input. The resistor R1 and R2 define the current level into the
current sense inputs of the SA2002H. At maximum rated
current the resistor values should be selected for input currents
of 16µA
Values for resistors R1 and R2 can be calculated as follows:
R1 = R2 = (I /16µA) x RSH/2
Where I = Line current
RSH = Shunt resistor or termination resistor if a CT is used as
the current sensor.
The value of RSH, if used as the CT's termination resistor,
should be less than the DC resistance of the CT's secondary
winding. The voltage drop across RSH should not be less than
16mV
Voltage Sense Input (IVP)
The current into the A/D converter should be set at 14µA
nominal mains voltage. The voltage sense input saturates at
an input current of ±25µA peak. Referring to figure 6 the typical
connections for the voltage sense input is illustrated. Resistors
R3, R4 and R5 set the current for the voltage sense input. The
mains voltage is divided down to 14V
A/D converter input is set at 14µA
http://www.sames.co.za
SA2002H
RMS
RMS
L
at rated currents.
.
L
set optimum bias conditions on chip.
RMS
via resistor R5.
RMS
. The current into the
RMS
at
6/12
OUTPUT SIGNALS
Pulse output (FOUT)
The output on FOUT is a pulse density signal representing the
instantaneous power/energy measurement as shown in figure
8. The pulse width on FOUT changes with the direction of
energy measurement by the device. The width of t is 71,5µs
for positive energy and doubles if negative energy is
measured. The output frequency may be calculated using the
following formula:
f = 11.16 x FOUT x ( I x I ) / I
Where:
FOUT = Typical rated output frequency (1360Hz)
I = Input current on current sense input (16µA at rated
conditions)
I = Input current on voltage sense input (16µA at rated
conditions)
I = Reference current on VREF typically 50µA
An integrated anti-creep function does not allow output pulses
on FOUT if no power is measured by the device.
I
V
R
v
POWER
V x I
FOUT
MAINS
DR-01282
Figure 8: FOUT instantaneous pulse output
I
V
R
2
t
P
sames
sames
p
t
t
t