Single Phase Bi-directional Power / Energy
Metering IC with Instantaneous Pulse Output
SA2002H
FEATURES
+ Functionally compatible with the SA9602H with reduced
external components
+ Bi-directional power and energy measurement
+ Meets the IEC 521/1036 Specification requirements for
Class 1 AC Watt hour meters
+ Protected against ESD
DESCRIPTION
The SAMES SA2002H is an enhancement of the SA9602H, as
the circuit contains the oscillator on chip.
The SAMES SA2002H single phase bi-directional
power/energy metering integrated circuit generates a pulse
rate output with a frequency proportional to the power
consumption.
The SA2002H performs a calculation for active power. The
method of calculation takes the power factor into account.
Energy consumption can be determined by the power
measurement being integrated over time.
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+ Total power consumption rating below 25mW
+ Adaptable to different types of current sensors
+ Operates over a wide temperature range
+ Precision voltage reference on-chip
+ Precision oscillator on-chip
This innovative universal single-phase power/energy metering
integrated circuit is ideally suited for energy calculations in
applications such as residential municipal metering and factory
energy metering and control.
The SA2002H integrated circuit is available in 8, 14 and 20 pin
dual-in-line plastic (DIP) as well as 16 and 20 pin small outline
(SOIC) package types.
V
V
DD
SS
IIP
IIN
ANALOG
SIGNAL
PROCESSING
IVP
GND
DR-01147
*FMO and DIR not availble in DIP-8 package type
POWER
INTEGRATOR
VOLTAGE
REF.
VREF
Figure 1: Block diagram
POWER
TO
FREQUENCY
TIMINGOSC
FOUT
DIR*
FMO*
SA2002H (REV. 5)
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17-08-00
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SA2002H
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ELECTRICAL CHARACTERISTICS
(V = 2.5V, V = -2.5V, over the temperature range -10°C to +70°C , unless otherwise specified.)
DDSS
Parameter
Operating temp. Range
Supply Voltage: Positive
Supply Voltage: Negative
Supply Current: Positive
Supply Current: Negative
Symbol
T
O
V
DD
V
SS
I
DD
I
SS
Min
-25
2.25
-2.75-2.25
#
Typ
Max
+85
2.75
3
3
5
5
Current Sensor Inputs (Diffferential)
Input Current Range
I
II
-25
+25
Voltage Sensor Input (Asymmetrical)
Input Current Range
Pin FOUT, FMO, DIR
Output High Voltage
Output Low Voltage
Pulse Rate FOUT
Pulse Width FOUT
Pin VREF
Ref. Current
Ref. Voltage
I
IV
V
OL
V
OH
f
p
t
pp
t
pn
-I
R
V
R
-25
V-1
DD
5
0
45
1.1
1360
71.55
143.1
50
+25
V+1
SS
1600
3000
55
1.3
# Extended Operating Temperature Range available on request.
Unit
°C
V
V
mA
mA
µA
µA
V
V
Hz
Hz
Hz
µs
µs
µA
V
Condition
Peak value
Peak value
At rated input conditions
Specified linearity
Min and Max frequency
Positive energy flow
Negative energy flow
With R = 24kW
connected to V
Reference to V
SS
SS
ABSOLUTE MAXIMUM RATINGS*
ParameterSymbolMinMaxUnit
Supply Voltage V -V-0.36.0V
Current on any pinI-150+150mA
Storage TemperatureT-40+125°C
Operating Temperature T-25+85°C
*Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress
rating only. Functional operation of the device at these or any other condition above those indicated in the operational sections of
this specification, is not implied. Exposure to Absolute Maximum Ratings for extended periods may affect device reliability.
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DDSS
PIN
STG
O
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3
Page 3
SA2002H
PIN DESCRIPTION
8
Pin
8
4
14
Pin
Pin
141620GND
558
16
20
Pin
DesignationDescription
Analog Ground. The voltage to this pin should be mid-way
between V and V .
Positive supply voltage. The voltage to this pin is typically +2.5V
V
DD
if a shunt resistor is used for current sensing or in the case of a
current transformer a +5V supply can be applied.
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DDSS
6
7
1, 2
10
9
131519
1, 21, 21, 2
3333
5
N.A.
N.A.
86
97
1111
444
685
7106
12127
13
1410
14
12
13
15
11
16
17
18
Negative supply voltage. The voltage to this pin is typically -2.5V
V
SS
if a shunt resistor is used for current sensing or in the case of a
current transformer a 0V supply can be applied.
Analog Input for Voltage. The current into the A/D converter
IVP
should be set at 14µA at nominal mains voltage. The
RMS
voltage sense input saturates at an input current of ±25µA peak.
Inputs for current sensor. The shunt resistor voltage from each
IIN, IIP
channel is converted to a current of 16µA at rated conditions.
The current sense input saturates at an input current of ±25µA
RMS
peak.
This pin provides the connection for the reference current setting
VREF
resistor. A 24kW resistor connected to V set the optimum
SS
operating condition.
FOUT
DIR
FMO
TP1
Pulse rate output. Refer to pulse output format for a description
of the pulse rate.
Direction output. The direction of the energy flow is indicated on
this output.
Voltage sense zero crossover. The FMO output generates pulses
on energy rising edge of the mains voltage.
The SA2002H is a CMOS mixed signal Analog/Digital
integrated circuit, which performs power/energy calculations
across a power range of 1000:1, to an overall accuracy of
better than Class 1.
The integrated circuit includes all the required functions for 1phase power and energy measurement such as two
oversampling A/D converters for the voltage and current sense
inputs, power calculation and energy integration. Internal
offsets are eliminated through the use of cancellation
procedures. The SA2002H generates pulses, the frequency of
which is proportional to the measured power consumption.
One frequency output (FOUT) is available. The pulse rate
follows the instantaneous power consumption measured.
POWER CALCULATION
In the application circuit (figure 6), the voltage drop across the
shunt will be between 0 and 16mV (0 to 80A through a shunt
resistor of 200µW) The voltage is converted to a current of
between 0 and 16uA, by means of resistors R1 and R2. The
RMS
current sense inputs saturates at an input current of ±25µA
peak.
RMS
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For the voltage sensor input, the mains voltage (230VAC) is
divided down through a divider (R3, R4 and P1) to 14V. The
current into the A/D converter input is set at 14µA at nominal
mains voltage, via resistor R5 (1MW). P1 may be varied for
calibration purposes.
In this configuration, with a mains voltage of 230V and a
current of 80A, the output frequency measured on the FOUT
pin is 1360Hz. In this case one pulse on FOUT correspond to
an energy consumption of 18.4kW/1360Hz = 13.53Ws.
ANALOG INPUT CONFIGURATION
The input circuitry of the current and voltage sensor inputs is
illustrated in figure 7. These inputs are protected against
electrostatic discharge through clamping diodes. The
feedback loops from the outputs of the amplifiers A and A
generate virtual shorts on the signal inputs. Exact duplications
of the input currents are generated for the analog signal
processing circuitry.
RMS
RMS
IV
VDD
N
Supply
L
GND
R3
GND
R1
R2
R5
R4
GND
P1
RSH
N
L
Figure 6: Application circuit
R6
DR-01587
U1
IIN
IIP
IVP
GND
VREF
VSS
VDD
FOUT
FMO
VSS
SA2002H
VSS
DIR
VDD
Pulse output
Fwd/Rev. Energy
Zero crossing
Figure 7: Internal analog input configuration
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Page 6
SA2002H
POWER
DR-01282
FOUT
V x I
v
MAINS
P
t
t
t
t
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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 24kW set optimum bias conditions on chip.
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.
RMS
L
L
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
IV R
2
Where:
FOUT = Typical rated output frequency (1360Hz)
I = Input current on current sense input (16µA at rated
I
conditions)
I = Input current on voltage sense input (16µA at rated
V
conditions)
I = Reference current on VREF typically 50µA
R
An integrated anti-creep function does not allow output pulses
on FOUT if no power is measured by the device.
p
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 at rated currents.
RMS
Voltage Sense Input (IVP)
The current into the A/D converter should be set at 14µA at
RMS
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. The current into the
A/D converter input is set at 14µA via resistor R5.
RMS
RMS
Figure 8: FOUT instantaneous pulse output
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Page 7
SA2002H
DR-01283
DIR
V
I
DIR
t
t
t
t
DR-01284
FMO
MAINS
t
V
t
t
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Direction indication (DIRO)
Note that the DIR output is not available in the DIP-8 package
type. Figure 9 shows the behavior of DIR, when energy
reversal takes place. The time period for the DIR signal to
change state, t , is the time it takes for the internal integrator
DIR
to count (down) from its present value to zero. Thus the energy
consumption rate determines the speed of change on DIR.
Figure 9: Measured energy direction on DIR
Mains zero crossing indication (FMO)
Note that the FMO output is not available in the DIP-8 package
type. The square wave signal of FMO indicates the polarity of
the mains voltage. Due to comparator offsets, the FMO low to
high transition can occur within a range as shown in figure 10.
The time between successive low to high transitions will be
equal to the mains voltage period.
Figure 10: Mains zero crossings on FMO
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Page 8
SA2002H
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TYPICAL APPLICATION
In figure 11, the components required for stand alone power
metering application, is shown. The application uses a shunt
resistor for the mains current sensing. The meter is designed
for 220V/40A I operation. The most important external
components for the SA2002H integrated circuit are the current
sense resistors, the voltage sense resistors as well as the bias
setting resistor.
BIAS RESISTOR
R13 defines all on-chip and reference currents. With
R13=24kW, optimum conditions are set. Device calibration is
done on the voltage input of the device.
SHUNT RESISTOR
The voltage drop across the shunt resistor at rated current
should be at least 20mV. A shunt resistor with a value of 625µW
is chosen. The voltage drop across the shunt resistor is 25mV
at rated conditions (Imax). The power dissipation in the current
sensor is:
P=(40A)² x 625µW = 1W.
CURRENT SENSE RESISTORS
The resistors R6 and R7 define the current level into the
current sense inputs of the device. The resistor values are
selected for an input current of 16µA on the current inputs of
the SA2002H at rated conditions. According to equation
described in the Current Sense inputs section:
MAX
VOLTAGE DIVIDER
The voltage divider is calculated for a voltage drop of 14V +
5%(14.7V). Equations for the voltage divider in figure 9 are:
RA = R1 + R2 + R3
RB = R12 || (R11+P1)
Combining the two equations gives:
(RA + RB) / 220V = RB / 14.7V
A 5k trimpot will be used in the voltage channel for meter
calibration. The center position on the pot is used in the
calculations. P1 = 2.5kW and values for resistors R11 = 22kW
and R12 =1MW is chosen.
Substituting the values will result in:
RB = 23.91kW
RA = RB x (230V/14.7V - 1) = 333kW so the resistor values of
R1, R2 and R3 are chosen to be 110kW.
R6 = R7 = ( I / 16µA ) x RSH / 2
= 40A / 16µA x 625µW / 2
= 781.2W
A resistor with value of 820W is chosen, the 5% deviation from
the calculated value will be compensated for when calculating
resistor values for the voltage path.
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L
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Page 9
SA2002H
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P1
C2
+2V5
D3
R4
+C3
D1
C5
C1
D4
+C4
D2
R11
DIR
FMO
R12
-2V5
14
13
12
IVP
GND
R5
R3
R2
R1
IIP
IIN
U1
3
2
1
R6
R7
10
11
TP4
FMO
VREF
TP14VDD5TP26TP3
+2V5
R13
VSS
FOUT
8
9
DIR
7
dr-01588
FOUT
SA2002H
C6
-2V5
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R8
LIVE
NEUTRAL
R10
Figure 11: Application circuit using a shunt resistor for current sensing.
9/12
LIVE
NEUTRAL
Page 10
SA2002H
Parts List for Application Circuit: Figure 10
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Symbol
U1
D1
D2
D3
D4
R1
R2
R3
R4
R5
R6
R7
R8
R10
R11
R12
R13
P1
C1
C2
C3
C4
C5
C6
Note 1: Resistor (R6 and R7) values are dependant on the selected shunt resistor (R14) value.
Note 2: Capacitor C6 to be positioned as close as possible to supply pins.
Description
SA2002H
Diode, Silicon, 1N4002
Diode, Silicon, 1N4002
Diode, Zener, 2.4V
Diode, Zener, 2.4V
Resistor, 110k, 1/4W, 1% metal
Resistor, 110k, 1/4W, 1% metal
Resistor, 110k, 1/4W, 1%, metal
Resistor, 680, 1/4W, 1%, metal
Resistor, 680, 1/4W, 1%, metal
Resistor, 820, 1/4W, 1%, metal
Resistor, 820, 1/4W, 1%, metal
Resistor, 47R, 2W, 5%, wire wound
Shunt resistor
Resistor, 22k 1/4W, 1%, metal
Resistor, 1M, 1/4W, 1%, metal
Resistor, 24k, 1/4W, 1%, metal
Trim pot, 5k, Multi turn
Capacitor, 220nF
Capacitor, 220nF
Capacitor, 100uF, 16V, electrolytic
Capacitor, 100uF, 16V, electrolytic
Capacitor, 330nF, 250VAC
Capacitor, 820nF
Detail
DIP-14
Note 1
Note 1
Note 2
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Page 11
SA2002H
NOTES:
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Page 12
PM9607AP
SA2002H
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DISCLAIMER:
The information contained in this document is confidential and proprietary to South African Micro-Electronic Systems (Pty) Ltd
("SAMES") and may not be copied or disclosed to a third party, in whole or in part, without the express written consent of SAMES.
The information contained herein is current as of the date of publication; however, delivery of this document shall not under any
circumstances create any implication that the information contained herein is correct as of any time subsequent to such date.
SAMES does not undertake to inform any recipient of this document of any changes in the information contained herein, and
SAMES expressly reserves the right to make changes in such information, without notification, even if such changes would render
information contained herein inaccurate or incomplete. SAMES makes no representation or warranty that any circuit designed by
reference to the information contained herein, will function without errors and as intended by the designer.
Any sales or technical questions may be posted to our e-mail address below:
For the latest updates on datasheets, please visit our web site:
SOUTH AFRICAN MICRO-ELECTRONIC SYSTEMS
DIVISION OF LABAT TECHNOLOGIES (PTY) LTD
P O BOX 15888
33 ELAND STREET
LYNN EAST 0039
REPUBLIC OF SOUTH AFRICA
energy@sames.co.za
http://www.sames.co.za.
Tel : (012) 333-6021
Tel: Int +27 12 333-6021
Fax: (012) 333-8071
Fax: Int +27 12 333-8071
33 ELAND STREET
KOEDOESPOORT INDUSTRIAL AREA
PRETORIA
REPUBLIC OF SOUTH AFRICA
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