Single Phase Bidirectional Dual Element
Power/Energy Metering IC with Pulse Output
sames
SA2007H
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
+
+
+
+
+
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
hour meters
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.
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.
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.
IIP1
CURRENT
IIN1
CHANNEL 1
X POWER 1
POWER TO
PULSE RATE
P1
D1
OMODE
IVP
OUTPUT
VOLTAGE
CONTROL
AGND
RP
INT
IIP2
CURRENT
IIN2
CHANNEL 2
X POWER 2
POWER TO
PULSE RATE
P2
D2
FMO
VOLTAGE
REF.
OSC
TIMING
dr-01623
VDD
VSS
VREF
TCLK
TEST
Figure 1: Block diagram
SPEC-0116 (REV. 1)
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PRELIMINARY
15-01-01
sames
SA2007H
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
5
6
mA
Supply Current: Negative
ISS
5
6
mA
Parameter
Condition
Current Sensor Inputs (Differential)
Input Current Range
III
-25
+25
µA
Peak value
IIV
-25
+25
µA
Peak value
-IR
VR
45
1.1
55
1.3
µA
V
With R = 24kW
connected to VSS
Reference to VSS
Pins P1, P2, D1, D2, FMO, INT
Output High Voltage
Output Low Voltage
VOH
VOL
VDD-1
VSS+1
V
V
Pins TCLK, TEST, OMODE, RP
Input High Voltage
Input Low Voltage
VIH
VIL
VDD-1
VSS+1
V
V
Pulse Rate P1, P2
fp
Voltage Sensor Input (Asymmetrical)
Input Current Range
Pin VREF
Ref. Current
Ref. Voltage
50
Digital I/O
Pulse Width P1, P2
tpp
tpn
Pins TCLK, TEST, RP, OMODE
Pull down current
IIL
1360
5
0
1600
3000
71.55
143.1
48
110
IOH = -2mA
IOL = 5mA
Hz
Hz
Hz
µs
µs
At rated input conditions
Specified linearity
Min and Max frequency
µA
V1 = VDD
Positive energy flow
Negative energy
#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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PRELIMINARY
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SA2007H
PIN DESCRIPTION
PIN
Designation
Description
20
AGND
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.
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.
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,
3, 4
IIN1, IIP1
IIN2, IIP2
5
VREF
This pin provides the connection for the reference current setting resistor. A 24kW resistor
connected to VSS sets the optimum operating condition.
6
OMODE
This logic input is used to select between latched or unlatched condition for the pulse and
direction outputs.
7
RP
A logic input is used to reset the latched outputs which is required after an interrupt has
occurred.
9
FMO
10, 15
TCLK, TEST
12
INT
17, 13
P1, P2
Analog Ground. The voltage to this pin should be mid-way between VDD and VSS.
Inputs for current sensor - Channel 1 and Channel 2. 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.
The zero crossover of the voltage sense input is signaled on this pin.
Configure / Test inputs. For normal operations these pins must be connected to VSS.
This logic output will indicate a change in status of the pulse or direction outputs.
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 71.5µs for positive energy
and doubles for reverse energy.
18, 16
D1, D2
11
NC
Direction output. These outputs indicate the energy flow direction of each channel.
No Connection.
ORDERING INFORMATION
IIN1
1
20
AGND
IIP1
2
19
IVP
IIN2
3
18 D1
IIP2
4
17
P1
VREF
5
16
D2
OMODE
6
15
TEST
RP
7
14 VSS
VDD
8
13
P2
FMO
9
12
INT
TCLK
10
11
NC
Part Number
Package
SA2007HPA
DIP-20
SA2007HSA
SOIC-20
DR-01620
Figure 2: Pin connections: Package: DIP-20, SOIC-20
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SA2007H
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.
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 R10 and R11 (channel
1) as well as R12 and R13. (channel 2). The current sense input
saturates at an input current of ±25µA peak.
The integrated circuit includes all the required functions for 1phase 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.
The mains voltage (230VAC) is divided down through a divider
to 14VRMS. The current into the A/D converter input is set at
14µARMS at nominal mains voltage, via resistor R7 (1MW).
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.
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 AI and AV
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.
V DD
IIP
CURRENT
SENSOR
INPUTS
VSS
AI
VDD
IIN
VSS
VDD
IVP
VOLTAGE
SENSOR
INPUT
V SS
AV
GND
DR-01288
Figure 3: Analog input internal configuration
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PRELIMINARY
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SA2007H
INPUT SIGNALS
OUTPUT SIGNALS
Voltage reference (VREF)
A bias resistor of 24kW sets optimum bias conditions on chip.
Calibration of the SA2007H should be done in the microcontrollers software.
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 tp on P1 and P2 change with the
direction of energy measurement tp is 71.5µs for positive
energy and doubles (143µS) if negative energy is measured.
The output frequency may be calculated using the following
formula:
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.
OMODE
f = 11.16 x FOUT x ( II x I V ) / IR2
Where:
FOUT=
II
=
Description
0
Fixed width mode
1
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.
IV
=
IR
=
Typical rated output frequency (1360Hz)
Input current on current sense input (16µA at rated
conditions)
Input current on voltage sense input (14µA at rated
conditions)
Reference current on VREF typically 50µA
An integrated anti-creep function does not allow output pulses
on P1 or P2 if no power is measured by the device.
vMAINS
t
Test Inputs (TEST, TCLK)
For normal operations these pins must be connected to VSS.
POWER
VxI
t
FOUT
t
DR-01282
tP
Figure 4: FOUT instantaneous pulse output
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).
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PRELIMINARY
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SA2007H
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.
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, tDIR, is the time it takes for the internal integrator
to count (down) from its present value to zero. Thus the energy
consumption rate determines the speed of change on the
direction outputs.
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).
I
t
V
t
FMO
D1, D2
t
DR-01283
P1
t DIR
Figure 5: Measured energy direction on D1 or D2
P2
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.
INT
RP
dr-01621
Figure 7: Output signals in latched mode
V
t
FMO
t
t MAINS
DR-01284
Figure 6: Mains zero crossing on FMO
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PRELIMINARY
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SA2007H
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 (Imax for the meter).
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 16µA at rated
conditions. For a 60A meter and a CT Ratio of 2500:1 the
resistor values are calculated as follows:
R10 = R11 = ( I / 16µA ) x RSH / 2
= 60A / 2500 / 16µA x 3.6W / 2
= 2.7kW
IL = Line current
RSH = CT Termination resistor
2500 = CT ratio
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 = 1.013µF
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.
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 14µA at nominal mains voltage. This voltage input saturates
at approximately 17µA. At a nominal voltage current of 14µA
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.
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PRELIMINARY
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SA2007H
NEUTRAL
VDD
U1
LIVE
D1
D3
3
Vout
R4
R14
C2
2
L
Vin
GND
1
T1
TZ1
p
GND
+ C5
s
+ C6
R15
D2
D4
C3
GND
R5
VSS
R1
R2
R3
14V
C1
CT2
R7
R8
CT1
GND
R9
U2
R10
1
R11
2
R12
3
R13
4
5
VDD
6
GND
7
8
R6
9
C4
10
IIN1
GND
IIP1
IVP
IIN2
D1
IIP2
P1
VREF
OMODE
RP
D2
TEST
VSS
VDD
P2
FMO
INT
TCLK
20
19
18
Energy Dir CH1
17
Energy Pulse CH1
16
Energy Dir CH1
15
14
13
12
VSS
Energy Pulse CH2
Inrerrupt
11
SA2007H
LIVE
VSS
VSS
Zero Crossings
RST Interrupt
NEUTRAL
Figure 8: Application circuit showing metering section
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PRELIMINARY
Micro
Controller
sames
SA2007H
Parts List for Application Circuit: Figure 8
Item
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
Symbol
U2
D1
D2
D3
D4
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
C1
C2
C3
C4
C5
C6
CT1
CT2
T1
U1
TZ1
Detail
DIP-20/SOIC-20
or Similar
or Similar
or Similar
or Similar
Description
SA2007H
Diode, Silicon 1N4148
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, 820nF
Capacitor, 2200µF, 25V, electrolytic
Capacitor, 100µF, 16V, electrolytic
Current Transformer
Note 2
Note 2
Note 1
Note 1
Note 1
Note 1
Note 4
Note 3
Current Transformer
Transformer, 230V/9V
78LC05, Voltage regulator
400V, Metal oxide varistor
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 (VDD & VSS) of U-1, as possible.
Note 4: Capacitor (C1) selected to minimize phase error introduced by current transformer (typically 1.5µF for normal CTs)
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PM9607AP
SA2007H
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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