Single Phase Uni-directional Power / Energy
Metering IC with Instantaneous Pulse Output
sames
SA2002E
+ FEATURES
+ Functionally compatible with the SA9602E with reduced
+
+
+
+
+
external components
+
+
Uni-directional power and energy measurement
Meets the IEC 521/1036 Specification requirements for
Class 1 AC Watt hour meters
+
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
Protected against ESD
DESCRIPTION
The SAMES SA2002E is an enhancement of the SA9602E, as
the circuit contains the 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 SAMES SA2002E single phase uni-directional
power/energy metering integrated circuit generates a pulse
rate output with a frequency proportional to the power
consumption.
The SA2002E 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.
The SA2002E 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.
VDD
IIP
VSS
FOUT
POWER
IIN
POWER
INTEGRATOR
TO
ANALOG
FREQUENCY
SIGNAL
VOLTAGE
PROCESSING
REF.
IVP
OSC
GND
TIMING
DR-01586
VREF
Figure 1: Block diagram
SA2002E (REV. 5)
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SA2002E
ELECTRICAL CHARACTERISTICS
(VDD = 2.5V, VSS = -2.5V, over the temperature range -10°C to +70°C#, unless otherwise specified.)
Symbol
Min
Operating temp. Range
TO
Supply Voltage: Positive
Typ
Max
Unit
-25
+85
°C
VDD
2.25
2.75
V
Supply Voltage: Negative
VSS
-2.75
-2.25
V
Supply Current: Positive
IDD
3
5
mA
Supply Current: Negative
ISS
3
5
mA
Parameter
Condition
Current Sensor Inputs (Diffferential)
Input Current Range
III
-25
+25
µA
Peak value
IIV
-25
+25
µA
Peak value
VOL
VOH
fp
VDD-1
Voltage Sensor Input (Asymmetrical)
Input Current Range
Pin FOUT
Output High Voltage
Output Low Voltage
Pulse Rate FOUT
-IR
VR
55
1.3
µA
V
1360
5
0
Pin VREF
Ref. Current
Ref. Voltage
1600
3000
V
V
Hz
Hz
Hz
VSS+1
45
1.1
50
At rated input conditions
Specified linearity
Min and Max frequency
With R = 24kW
connected to VSS
Reference to VSS
# Extended Operating Temperature Range available on request.
ABSOLUTE MAXIMUM RATINGS*
Parameter
Symbol
Min
Max
Unit
Supply Voltage
VDD -VSS
-0.3
6.0
V
Current on any pin
IPIN
-150
+150
mA
Storage Temperature
TSTG
-40
+125
°C
Operating Temperature
TO
-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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SA2002E
PIN DESCRIPTION
8
Pin
14
Pin
16
Pin
20
Pin
Designation
8
14
16
20
GND
4
5
5
8
VDD
Positive supply voltage. The voltage to this pin is typically +2.5V
if a shunt resistor is used for current sensing or in the case of a
current transformer a +5V supply can be applied.
6
10
12
14
VSS
Negative supply voltage. The voltage to this pin is typically -2.5V
if a shunt resistor is used for current sensing or in the case of a
current transformer a 0V supply can be applied.
7
13
15
19
IVP
Analog Input for Voltage. 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.
1, 2
1, 2
1, 2
1, 2
IIN, IIP
3
3
3
3
VREF
5
8
6
12
FOUT
4
4
4
TP1
6
7
5
TP2
7
8
6
TP3
9
9
7
TP4
11
10
9
TP5
12
11
10
TP6
13
11
TP7
14
13
TP8
15
TP9
16
TP10
17
TP11
18
TP12
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Description
Analog Ground. The voltage to this pin should be mid-way
between VDD and VSS.
Inputs for current sensor. The shunt resistor voltage from each
channel is converted to a current of 16µARMS at rated conditions.
The current sense input saturates at an input current of ±25µA
peak.
This pin provides the connection for the reference current setting
resistor. A 24kW resistor connected to VSS set the optimum
operating condition.
Pulse rate output. Refer to pulse output format for a description
of the pulse rate.
Leave pins unconnected.
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SA2002E
IIN
1
14
GND
IIP
2
13
IVP
VREF
3
12
TP6
TP1
4
11
TP5
IIN
1
8
GND
IIP
2
7
IVP
VDD
5
10
VSS
VREF
3
6
VSS
TP2
6
9
TP4
VDD
4
5
FOUT
TP3
7
8
FOUT
dr-01484
dr-01485
Figure 2: Pin connections: Package: DIP-8
IIN
1
16
GND
IIP
2
15
IVP
VREF
3
14
TP8
TP1
4
13
TP7
VDD
5
12
VSS
FOUT
6
11
TP6
TP2
7
10
TP5
TP3
8
9
TP4
Figure 3: Pin connections: Package: DIP-14
1
20
GND
IIP
2
19
IVP
VREF
3
18
TP12
TP1
4
17
TP11
TP2
5
16
TP10
TP3
6
15
TP9
TP4
7
14
VSS
VDD
8
13
TP8
TP5
9
12
FOUT
TP6
10
11
TP7
DR-01483
DR-01486
Figure 4: Pin connections: Package: SOIC-16
Figure 5: Pin connections: Package: DIP-20, SOIC-20
ORDERING INFORMATION
Part Number
Package
SA2002EPA
DIP-8
SA2002EPA
DIP-14
SA2002EPA
DIP-20
SA2002ESA
SOIC-16
SA2002ESA
SOIC-20
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IIN
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SA2002E
FUNCTIONAL DESCRIPTION
The SA2002E 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 SA2002E 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 16mVRMS (0 to 80A through a shunt
resistor of 200µW) The voltage is converted to a current of
between 0 and 16uARMS, by means of resistors R1 and R2. The
current sense inputs saturates at an input current of ±25µA
peak.
For the voltage sensor input, the mains voltage (230VAC) is
divided down through a divider (R3, R4 and P1) to 14VRMS. The
current into the A/D converter input is set at 14µARMS 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 AI and AV
generate virtual shorts on the signal inputs. Exact duplications
of the input currents are generated for the analog signal
processing circuitry.
V DD
IIP
CURRENT
SENSOR
INPUTS
VDD
N
VSS
AI
VDD
Supply
IIN
L
GND
VSS
VSS
RSH
U1
R1
VDD
IIN
VDD
VDD
R2
IIP
IVP
R3
R5
IVP
FOUT
Pulse output
VOLTA GE
SENSOR
INPUT
GND
R4
V SS
AV
GND
VREF
N
P1
R6
VSS
SA2002E
GND
L
DR-01584
GND
DR-01148
VSS
Figure 7: Internal analog input configuration
Figure 6: Application circuit
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SA2002E
ELECTROSTATIC DISCHARGE (ESD)
PROTECTION
The SA2002E integrated circuit's inputs/outputs are protected
against ESD.
POWER CONSUMPTION
The power consumption rating of the SA2002E integrated
circuit is less than 25mW.
INPUT SIGNALS
VREF
A bias resistor of 24kW set optimum bias conditions on chip.
Calibration of the SA2002E 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 SA2002E. At maximum rated
current the resistor values should be selected for input currents
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.
OUTPUT SIGNAL
Pulse output (FOUT)
The output on FOUT is a pulse density signal representing the
instantaneous power/energy measurement as shown in figure
8. The minimum timing characteristics are shown in the figure
9. The output frequency may be calculated using the following
formula:
f = 11.16 x FOUT x ( II x I V ) / IR2
Where:
FOUT = Typical rated output frequency (1360Hz)
II = Input current on current sense input (16µA at rated
conditions)
IV = Input current on voltage sense input (16µA at rated
conditions)
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.
vMAINS
t
POWER
VxI
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.
t
FOUT
t
DR-01282
tP
Voltage Sense Input (IVP)
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.
Figure 8: FOUT instantaneous pulse output
71µs
71µs min.
DR-01151
Figure 9: FOUT pulse width
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SA2002E
TYPICAL APPLICATION
VOLTAGE DIVIDER
In figure 10, 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 IMAX operation. The most important external
components for the SA2002E integrated circuit are the current
sense resistors, the voltage sense resistors as well as the bias
setting resistor.
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
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.
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.
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:
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.
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 SA2002E at rated conditions. According to equation
described in the Current Sense inputs section:
R6 = R7 = ( IL / 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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Figure 10: Application circuit using a shunt resistor for current sensing.
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LIVE
NEUTRAL
LIVE
NEUTRAL
R10
R8
R1
C5
R7
R6
R13
-2V5
+2V5
R2
D2
D1
C6
4
3
2
1
SA2002E
VDD
VREF
IIP
IIN
U1
R3
R5
+ C4
+ C3
R4
FOUT
VSS
IVP
GND
5
6
7
8
-2V5
DR-01585
D4
D3
C1
C2
R9
U2
+2V5
R12
+2V5
R11
P1
OC
OE
SA2002E
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SA2002E
Parts List for Application Circuit: Figure 10
Symbol
Description
U1
D1
D2
D3
D4
R1
R2
R3
R4
R5
R6
R7
R8
R9
SA2002E
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
Resistor, 680, 1/4W, 5%, carbon
R10
R11
R12
R13
Shunt resistor
Resistor, 22k 1/4W, 1%, metal
Resistor, 1M, 1/4W, 1%, metal
P1
C1
C2
C3
C4
C5
C6
U2
Note 1
Note 1
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
4N35, Opto Coupler
Note 2
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.
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Detail
DIP-8
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PM9607AP
SA2002E
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:
[email protected]
For the latest updates on datasheets, please visit our web site:
http://www.sames.co.za.
SOUTH AFRICAN MICRO-ELECTRONIC SYSTEMS
DIVISION OF LABAT TECHNOLOGIES (PTY) LTD
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
P O BOX 15888
33 ELAND STREET
LYNN EAST 0039
REPUBLIC OF SOUTH AFRICA
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