SA2002H
sames
ELECTROSTATIC DISCHARGE (ESD)
PROTECTION
OUTPUT SIGNALS
Pulse output (FOUT)
The SA2002H integrated circuit's inputs/outputs are protected
against ESD.
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 tp is 71,5µs
for positive energy and doubles if negative energy is
measured. The output frequency may be calculated using the
following formula:
POWER CONSUMPTION
The power consumption rating of the SA2002H integrated
circuit is less than 25mW.
2
INPUT SIGNALS
VREF
f = 11.16 x FOUT x ( II x IV ) / IR
A bias resistor of 24kW set optimum bias conditions on chip.
Calibration of the SA2002H should be done on the voltage
input as described in Typical Applications.
Where:
FOUT = Typical rated output frequency (1360Hz)
II = Input current on current sense input (16µA at rated
conditions)
Current sense input (IIP and IIN)
IV = Input current on voltage sense input (16µA at rated
conditions)
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
IR = 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.
of 16µARMS
.
Values for resistors R1 and R2 can be calculated as follows:
R1 = R2 = (IL /16µA) x RSH/2
Where IL = Line current
RSH = Shunt resistor or termination resistor if a CT is used as
the current sensor.
v
MAINS
t
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
16mVRMS at rated currents.
POWER
V
x I
Voltage Sense Input (IVP)
t
t
The current into the A/D converter should be set at 14µARMS at
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 14VRMS. The current into the
A/D converter input is set at 14µARMS via resistor R5.
FOUT
DR-01282
t
P
Figure 8: FOUT instantaneous pulse output
6/12
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