FEATURES
+
Two current sensor inputs
+
Dual pulse and energy direction outputs
+
No external crystal or resonator required
+
Performs bi-directional power and energy measurement
+
Meets the IEC 521/1036 Specification for Class 1 AC Watt
hour meters
sames
sames
Single Phase Bidirectional Dual Element
Power/Energy Metering IC with Pulse Output
SA2007H
1/10
SPEC-0116 (REV. 1)
15-01-01
+
Protected against ESD
+
Total power consumption rating below 25mW
+
Adaptable to different types of sensors
+
Operates over a wide temperature range
+
Precision voltage reference on-chip
DESCRIPTION
The SAMES SA2007H is a single phase bidirectional dual
element energy metering integrated circuit. It provides a
simple analog interface to a micro-controller and is specifically
designed for meter manufacturers to have full control over the
meter functionality.
The SA2007H has two current sensor inputs. The power
consumption on both inputs are continuously measured. A
typical application would be to monitor Live and Neutral lines
for tamper detection.
For each current sensor input the SA2007H integrated circuit
has a corresponding pulse output, each generating a pulse
rate with a frequency proportional to the power consumption
measured on the specific channel.
The SA2007H performs active power measurement and takes
the power factor into account. Energy consumption can be
determined by the power measurement being integrated over
time. The energy flow direction information is also available for
each channel.
Figure 1: Block diagram
OUTPUT
CONTROL
POWER TO
PULSE RATE
POWER TO
PULSE RATE
CURRENT
CHANNEL 1
VOLTAGE
CURRENT
CHANNEL 2
VOLTAGE
REF.
OSC
TIMING
IIP1
IIN1
IVP
AGND
IIP2
IIN2
P1
D1
P2
D2
RP
OMODE
INT
TEST
TCLK
VREF
V
DD
V
SS
X
X
FMO
POWER 2
POWER 1
dr-01623
PRELIMINARY
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ELECTRICAL CHARACTERISTICS
#
(V = 2.5V, V = -2.5V, over the temperature range -10C to +70C , unless otherwise specified.)
DD
SS
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage
V -V
-0.3
6.0
V
DD
SS
Current on any pin
I
-150
+150
mA
PIN
Storage Temperature
T
-40
+125
C
STG
Operating Temperature
T
-25
+85
C
O
*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.
Parameter
Symbol
Min
Max
Unit
#Extended Operating Temperature Range available on request.
C
V
A
A
T
O
V
DD
I
II
I
IV
-25
-25
-25
2.25
+25
+25
+85
2.75
Peak value
Peak value
At rated input conditions
Specified linearity
Min and Max frequency
Condition
Unit
Max
Typ
Min
Symbol
Parameter
V
V
SS
-2.75
-2.25
I
DD
6
5
mA
I
SS
6
5
mA
Pins TCLK, TEST, OMODE, RP
Input High Voltage
Input Low Voltage
V
V
V -1
DD
V +1
SS
Pins P1, P2, D1, D2, FMO, INT
Output High Voltage
Output Low Voltage
V
V
V
OH
V
OL
V -1
DD
V +1
SS
Pulse Width P1, P2
s
s
With R = 24kW
connected to V
SS
Reference to V
SS
Pin VREF
Ref. Current
Ref. Voltage
A
V
45
1.1
55
1.3
-I
R
V
R
50
Hz
Hz
Hz
5
0
Pulse Rate P1, P2
I = -2mA
OH
I = 5mA
OL
Digital I/O
Operating temp. Range
Supply Voltage: Positive
Supply Voltage: Negative
Supply Current: Negative
Supply Current: Positive
Current Sensor Inputs (Differential)
Voltage Sensor Input (Asymmetrical)
Input Current Range
Input Current Range
f
p
Positive energy flow
Negative energy
V
IH
V
IL
1600
3000
1360
t
pp
t
pn
71.55
143.1
PRELIMINARY
Pins TCLK, TEST, RP, OMODE
Pull down current
A
V V
1 =
DD
I
IL
48
110
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Figure 2: Pin connections: Package: DIP-20, SOIC-20
Part Number
SA2007HPA
SA2007HSA
Package
DIP-20
SOIC-20
ORDERING INFORMATION
PIN DESCRIPTION
Analog Ground. The voltage to this pin should be mid-way between V and V .
DD
SS
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.
Description
PIN
20
8
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.
14
Analog Input for Voltage. The current into the A/D converter should be set at 14A
at
RMS
nominal mains voltage. The voltage sense input saturates at an input current of 25A peak.
19
Inputs for current sensor - Channel 1 and Channel 2. The shunt resistor voltage from each
channel is converted to a current of 16A
at rated conditions. The current sense input
RMS
saturates at an input current of 25A peak.
1, 2,
3, 4
This pin provides the connection for the reference current setting resistor. A 24kW resistor
connected to V
sets the optimum operating condition.
SS
5
This logic input is used to select between latched or unlatched condition for the pulse and
direction outputs.
6
A logic input is used to reset the latched outputs which is required after an interrupt has
occurred.
7
The zero crossover of the voltage sense input is signaled on this pin.
9
Configure / Test inputs. For normal operations these pins must be connected to V .
SS
10, 15
This logic output will indicate a change in status of the pulse or direction outputs.
12
Pulse outputs. The P1 and P2 outputs give instantaneous pulse outputs of channel 1 and
channel 2 respectively. The pulse is active low with a pulse width of 71.5s for positive energy
and doubles for reverse energy.
17, 13
Direction output. These outputs indicate the energy flow direction of each channel.
18, 16
No Connection.
11
DR-01620
1
IIN1
AGND
D2
IIP1
IVP
TEST
IIN2
D1
VSS
IIP2
VREF
OMODE
RP
VDD
P1
P2
INT
NC
TCLK
FMO
2
3
4
5
6
15
14
13
12
11
10
9
8
7
16
17
18
19
20
AGND
V
DD
Designation
V
SS
IVP
IIN1, IIP1
IIN2, IIP2
VREF
OMODE
RP
FMO
TCLK, TEST
INT
P1, P2
D1, D2
NC
PRELIMINARY
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SA2007H
Figure 3: Analog input internal configuration
http://www.sames.co.za
FUNCTIONAL DESCRIPTION
The SA2007H 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 1-
phase power and energy measurement such as 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.
Referring to the block diagram (figure 1) the SA2007H has two
current sense channels and a voltage sense channel. The
voltage measured is multiplied with the current measured on
the two channels. The multiplied signals from each current
channel is fed to separate power to pulse rate blocks.
The power to pulse rate blocks generate pulses at a frequency
proportional to the instantaneous active power measured.
Pulses on output P1 represent energy measured on current
channel 1. The pulses on output P2 represent energy
measured on current channel 2. Counting the pulses
generated represents the energy measured.
A typical application would be to simultaneous measure
energy/power consumption in both Live and Neutral lines. A
meter tamper condition could be detected when an imbalance
exists between the live and neutral energy/power measured.
Two modes of operation is available on the SA2007H, in one
mode the device is functionally the same as two SA2002H
devices sharing a common voltage channel. Alternatively the
pulse output is latched and an interrupt is generated on any
change of the pulse outputs.
POWER CALCULATION
In Figure 8, the voltage drops across the current transformers
terminating resistors are converted to currents for each
current sense input, by means of resistors R and R (channel
10
11
1) as well as R and R (channel 2). The current sense input
12
13.
saturates at an input current of 25A peak.
The mains voltage (230VAC) is divided down through a divider
to 14V
. The current into the A/D converter input is set at
RMS
14A
at nominal mains voltage, via resistor R (1MW).
RMS
7
In this configuration, with a mains voltage of 230V and a
current of 80A, the output frequency measured on P1 or P2 pin
is 1360Hz. In this case the energy associated with a single
pulse is 18.4kW/1360Hz = 13.5Ws per pulse.
ANALOG INPUT CONFIGURATION
The input circuitry of the current and voltage sensor inputs are
illustrated in figure 3. These inputs are protected against
electrostatic discharge through clamping diodes.
The feedback loops from the outputs of the amplifiers A and A
I
V
generate virtual shorts on the signal inputs. Exact duplications
of the input currents are generated for the analog signal
processing circuitry.
ELECTROSTATIC DISCHARGE (ESD)
PROTECTION
The SA2007H integrated circuit's input's/outputs are protected
against ESD.
POWER CONSUMPTION
The power consumption rating of the SA2007H integrated
circuit is less than 30mW.
VOLTAGE
SENSOR
INPUT
IVP
DR-01288
SS
V
CURRENT
SENSOR
INPUTS
IIP
IIN
SS
V
VDD
SS
V
VDD
DD
V
GND
A
V
A
I
PRELIMINARY
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SA2007H
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INPUT SIGNALS
Voltage reference (VREF)
A bias resistor of 24kW sets optimum bias conditions on chip.
Calibration of the SA2007H should be done in the micro-
controllers software.
Output Mode (OMODE)
The output behavior of the SA2007H is selectable between
fixed width outputs or latched outputs. In fixed width mode the
P1 and P2 output pulses stay at a fixed width. In latched mode
the status of P1 and P2 are cleared with a logic 1 on the RP pin.
Refer to the "Output signals in latched mode" section (Page 6)
for further information.
OUTPUT SIGNALS
Pulse outputs (P1, P2)
The output on P1 and P2 is a pulse density signal representing
the instantaneous power/energy measurement as shown in
figure 4. The pulse width t on P1 and P2 change with the
p
direction of energy measurement t is 71.5s for positive
p
energy and doubles (143S) if negative energy is measured.
The output frequency may be calculated using the following
formula:
2
f = 11.16 x FOUT x ( I x I ) / I
I
V
R
Where:
FOUT=
Typical rated output frequency (1360Hz)
I
= Input current on current sense input (16A at rated
I
conditions)
I
= Input current on voltage sense input (14A at rated
V
conditions)
I
=
Reference current on VREF typically 50A
R
An integrated anti-creep function does not allow output pulses
on P1 or P2 if no power is measured by the device.
Figure 4: FOUT instantaneous pulse output
POWER
DR-01282
FOUT
V x I
v
MAINS
P
t
t
t
t
OMODE
Description
0
1
Fixed width mode
Latched mode
Clear Interrupt (RP)
A logic 1 on the RP input is used to clear the interrupt
generated by the SA2007H when a pulse is generated on P1
or P2, while operating in latched mode. By clearing the
interrupt in latched mode the status of the pulse outputs will
also be cleared.
Test Inputs (TEST, TCLK)
For normal operations these pins must be connected to V .
SS
Direction indication (D1, D2)
The SA2007H provides information about the energy flow
direction of both current channels separately on pins D1 and
D2.
Logic 0 on pin D1 or D2 indicates reverse energy flow of that
particular channel. Reverse energy flow is defined as the
condition where the voltage sense input and current sense
input are out of phase (greater than 90 degrees).
PRELIMINARY
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SA2007H
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Figure 5: Measured energy direction on D1 or D2
Figure 6: Mains zero crossing on FMO
Figure 7: Output signals in latched mode
P1
P2
INT
RP
FMO
dr-01621
D1, D2
V
I
DR-01283
t DIR
t
t
t
DR-01284
FMO
MAINS
t
V
t
t
Positive energy flow, when voltage sense and both current
sense input are in phase, is indicated on pin D1 or D2 as a logic
1.
Figure 5 shows the behavior of D1 and D2, when energy
reversal takes place. The time period for the direction 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 the
direction outputs.
Mains zero crossing indication (FMO)
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 6. The
time between successive low to high transitions will be equal to
the mains voltage period.
Interrupt (INT)
While the SA2007H is operating in latched mode (see Output
mode description) an interrupt is generated with the falling
edge of the pulse outputs P1 and P2 (see figure 7). INT is
cleared with a logic 1 on the RP input.
OUTPUT SIGNALS IN LATCHED MODE
Latched mode is selected by setting the OMODE input to logic
1. This mode is used with a micro controller to ensure that any
simultaneous pulses on P1 and P2 are not missed. The
functionality of the latched mode is shown in figure 7.
An interrupt is generated with a falling edge on any of the pulse
output signals P1 and P2. The micro controller needs to scan
the status of the pulse outputs as well as the direction signals
D1 and D2 during its interrupt service routine. The micro
controller clears the interrupt by setting the RP input to a logic
1. The pulse outputs P1 and P2 are cleared along with the
interrupt. Note that energy pulses are inhibited when the
interrupt output is set (during latched mode).
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TYPICAL APPLICATION
The analog (metering) interface shown in figure 8, is designed
for measuring 230V/60A with precision better than Class 1.
The most important external components for the SA2007H
integrated circuit are the current sense resistors, the voltage
sense resistors and the bias setting resistor. The resistors
used in the metering section should be of the same type so
temperature effects are minimized.
Current Input IIN1, IIP1, IIN2, IIP2
Two current transformers are used to measure the current in
the live and neutral phases. The output of the current
transformer is terminated with a low impedance resistor. The
voltage drop across the termination resistor is converted to a
current that is fed to the differential current inputs of the
SA2007H.
CT Termination Resistor
The voltage drop across the CT termination resistor at rated
current should be at least 20mV. The CT's have low phase shift
and a ratio of 1:2500. The CT's are terminated with a 3.6W
resistor giving a voltage drop of 86.4mV across each
termination resistor at rated conditions (I for the meter).
max
Current Sensor Input Resistors
The resistors R10, R11 and R12, R13 define the current level
into the current sense inputs of the SA2007H. The resistor
values are selected for an input current of 16A at rated
conditions. For a 60A meter and a CT Ratio of 2500:1 the
resistor values are calculated as follows:
R10 = R11 = ( I / 16A ) x R / 2
SH
= 60A / 2500 / 16A x 3.6W / 2
= 2.7kW
I
= Line current
L
R = CT Termination resistor
SH
2500 = CT ratio
The two current channels are identical so R10 = R11 = R12 =
R13.
Voltage Input IVP
The voltage input of the SA2007H (IVP) is driven with a current
of 14A at nominal mains voltage. This voltage input saturates
at approximately 17A. At a nominal voltage current of 14A
allows for 20% overdriving. The mains voltage is divided with a
voltage divider to 14V that is fed to the voltage input pins via a
1MW resistor.
Voltage Divider
The voltage divider is calculated for a voltage drop of 14V.
Equations for the voltage divider are:
RA = R1 + R2 + R3
RA = R7 || (R5 + P1)
Combining the two equations gives:
(RA + RB) / 230V = RB / 14V
Values for resistors R4 = 10W, R5 - 22kW and R7 - 1MW is
chosen.
Substituting the values result in:
RB = 21.526kW
RA = RB x (230V / 14V -1)
RA = 332.12kW.
Standard resistor values for R1, R2 and R3 are chosen to be
100kW, 100kW and 120kW.
The capacitor C1 is used to compensate for phase shift
between the voltage sense inputs and the current sense inputs
of the device, in cases where CTs with phase errors are used.
The phase shift caused by the CT may be corrected by
inserting a capacitor in the voltage divider circuit. To
compensate for a phase shift of 0.18 degrees the capacitor
value is calculated as follows:
C = 1 / (2 x p x Mains frequency x R5 x tan (Phase shift angle))
C = 1 / ( 2 x p x 50 x 1MW tan (0.18 degrees ))
C = 1.013F
Reference Voltage Bias resistor
R6 defines all on chip and reference currents. With R6 = 24kW
optimum conditions are set. Calibration should be done in the
micro controller software.
PRELIMINARY
Figure 8: Application circuit showing metering section
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SA2007H
C3
C2
R1
R2
R3
R4
R5
R7
R8
R10
R11
VSS
LIVE
NEUTRAL
LIVE
NEUTRAL
CT1
CT2
R12
R13
R9
R6
L
14V
+
C5
p
s
T1
Vin
1
G
N
D
2
Vout
3
U1
R14
R15
D1
D2
D3
D4
+
C6
VDD
VDD
VSS
GND
TZ1
GND
IIP2
4
VREF
5
RP
7
OMODE
6
VDD
8
FMO
9
TCLK
10
IIN2
3
IIP1
2
IIN1
1
GND
20
IVP
19
D1
18
P1
17
D2
16
TEST
15
VSS
14
P2
13
INT
12
11
U2
SA2007H
VSS
VSS
RST Interrupt
Zero Crossings
Inrerrupt
Energy Pulse CH2
Energy Pulse CH1
Energy Dir CH1
Energy Dir CH1
Micro
GND
GND
C4
C1
Controller
PRELIMINARY
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SA2007H
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Item
Description
Detail
SA2007H
DIP-20/SOIC-20
Parts List for Application Circuit: Figure 8
Note 1: Resistor (R10, R11, R12 and R13) values are dependent upon the selected value of R8 and R9
Note 2: See TYPICAL APPLICATION when selected the value of R8 and R9.
Note 3: Capacitor (C4) to be positioned as closed to Supply Pins (V & V ) of U-1, as possible.
DD
SS
Note 4: Capacitor (C1) selected to minimize phase error introduced by current transformer (typically 1.5F for normal CTs)
Symbol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
U2
D1
D2
D3
D4
R1
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
C1
C2
C3
C4
C5
C6
CT1
CT2
T1
U1
R2
Diode, Silicon 1N4148
Diode, Silicon 1N4148
Diode, Silicon 1N4148
Resistor, 100k, 1/4W, 1%, metal
Resistor, 100k, 1/4W, 1%, metal
Resistor, 120k, 1/4W, 1%, metal
Resistor, 10W, 2W, Wire wound
Resistor, 24k, 1/4W, 1%, metal
Resistor, 24k, 1/4W, 1%, metal
Resistor, 1M, 1/4W, 1%, metal
Resistor, 3.6W, 1/4W, 1%, metal
Resistor, 3.6W, 1/4W, 1%, metal
Resistor, 2.7k, 1/4W, 1%, metal
Resistor, 2.7k, 1/4W, 1%, metal
Resistor, 2.7k, 1/4W, 1%, metal
Resistor, 2.7k, 1/4W, 1%, metal
Resistor, 1k, 1/4W
Resistor, 1k, 1/4W
Capacitor
Capacitor, 220nF
Capacitor, 220nF
Capacitor, 2200F, 25V, electrolytic
Capacitor, 820nF
Capacitor, 100F, 16V, electrolytic
Current Transformer
Current Transformer
Transformer, 230V/9V
78LC05, Voltage regulator
400V, Metal oxide varistor
Note 1
Note 1
Note 3
Diode, Silicon 1N4148
TZ1
Note 4
Note 1
Note 1
Note 2
Note 2
or Similar
or Similar
or Similar
or Similar
PRELIMINARY
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PM9607AP
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SA2007H
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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:
energy@sames.co.za
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 12 333-807
1
P O BOX 15888
33 ELAND STREET
LYNN EAST 0039
REPUBLIC OF SOUTH AFRICA
33 ELAND STREET
KOEDOESPOORT INDUSTRIAL AREA
PRETORIA
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