sames
SA9605A
THREE PHASE POWER/ENERGY METERING
IC WITH INSTANTANEOUS PULSE OUTPUT
FEATURES
n
Functionally similar to the SA9105E
and SA9105F, with reduced number of
external components
n
Output frequency represents the absolute sum of energy on all three phases
n
Performs one, two or three phase power
and energy measurement
n
Meets the IEC 521/1036 Specification
requirements for Class 1 AC Watt hour
meters
n
n
n
n
n
n
n
Operates over a wide temperature
range
Current transformers for sensing
Excellent long term stability
Easily adaptable to different signal
levels
Precision voltage reference on-chip
Pin selectable pulse rates
Supports tamper detection
PIN CONNECTIONS
DESCRIPTION
The SAMES SA9605A is an enhancement
of the SA9105E and SA9105F, as no external
capacitors are needed for the A/D converters.
The SAMES SA9605A Three Phase Power/
Energy metering integrated circuit generates
a pulse rate output, the frequency of which
1
20
IIP2
is proportional to the absolute power con2
19
IIN2
sumption. The SA9605A performs the
18
3
IVN3
calculation for active power.
17
4
IIP3
The method of calculation takes the power
16
5
IIN3
factor into account.
VDD
6
15
Energy consumption is determined by the
14
FOUT1 7
power measurement being integrated over
13
8
time.
FOUT2
12
9
DIR
The output of this innovative universal three
phase power/energy metering integrated
11
10
OSC1
circuit, is ideally suited for applications such
DR-01109
as residential and industrial energy metering
and control.
The SA9605A integrated circuit is available
Package: DIP-20
in both 20-pin dual-in-line plastic (DIP-20),
SOIC-20
as well as 20-pin plastic small outline (SOIC20) package types.
IVP2
IIN1
IIP1
IVN1
GND
VREF
VSS
PGM1
PGM0
OSC2
1/14
4452
PDS039-SA9605A-001
Rev. B
14-03-97
SA9605A
BLOCK DIAGRAM
VD D VS S
PGM0 PGM1
IVN1
IVN2
ANALOG
IVN3
POWER
INTEG.
SIGNAL
IIP1
IIN1
PRO-
IIP2
IIN2
CESSING
FOUT1
TO
FOUT2
&
PULSE
DIR
AVERAGE
RATE
IIP3
IIN3
GND
OSC1
VREF
REF
TIMING & CONTROL
OSC
OSC2
DR-01110
ABSOLUTE MAXIMUM RATINGS *
Parameter
Symbol
Supply Voltage
VDD-VSS
Current on any Pin
IPIN
Storage Temperature
TSTG
Operating Temperature
TO
Current at any pin
IP
Min
Max
Unit
-0.3
-150
-40
-40
-100
6.0
+150
+125
+85
+100
V
mA
°C
°C
mA
* 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 conditions above those indicated in the operation sections of this
specification, is not implied. Exposure to Absolute Maximum Ratings for extended
periods may affect device reliability.
2/14
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SA9605A
ELECTRICAL CHARACTERISTICS
(VDD = 2.5V, VSS = -2.5V, over the temperature range -10°C to +70°C#, unless otherwise
specified.)
Parameter
Operating Temperature
Range #
Symbol
Min Typ
Max Unit Condition
TO
-25
+85
°C
Supply Voltage
Supply Current
Nonlinearity of
Power Calculation
VDD-VSS
IDD
4.5
5.5
15
V
mA
-0.3
+0.3
%
1% - 100% of
rated power
-25
+25
µA
Peak value
-25
+25
µA
Peak value
V SS+1
V
V
IOL = 5mA
IOH = -2mA
1160
3000
Hz
Hz
Current Sensor Inputs (Differential)
Input Current Range
III
Voltage Sensor Inputs (Asymmetric)
Input Current Range
IIV
Pins FOUT1, FOUT2, DIR
Output Low Voltage
VOL
Output High Voltage
VOH
Pulse Rate:
FOUT1
fp
VDD-1
10
FOUT2
Oscillator
Ref. Current
Recommended crystal:
TV colour burst crystal, f = 3.5795 MHz
With R = 24 kΩ
-IR
45
50
55
µA connected to VSS
Ref. Voltage
VR
Pin VREF
#
Specified linearity
Min and max limits
User selectable
1.1
1.3
V
Referred to VSS
Extended Operating Temperature Range available on request.
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SA9605A
PIN DESCRIPTION
Pin
Designation
Description
16
6
GND
VDD
Positive Supply Voltage
Ground
14
V SS
Negative Suply Voltage
17
20
3
19
18
2
1
5
4
10
11
7
8
9
12
13
15
IVN1
IVN2
IVN3
IIN1
IIP1
IIN2
IIP2
IIN3
IIP3
OSC1
OSC2
FOUT1
FOUT2
DIR
PGM0
PGM1
VREF
Analog input for Voltage : Phase 1
Analog input for Voltage : Phase 2
Analog input for Voltage : Phase 3
Inputs for Current sensor : Phase 1
Inputs for Current sensor : Phase 2
Inputs for Current sensor : Phase 3
Connections for crystal or ceramic resonator
(OSC1 = Input ; OSC2 = Output)
Pulse rate outputs
Direction indicator
FOUT2 Frequency select pins
Connection for current setting resistor
FUNCTIONAL DESCRIPTION
The SAMES SA9605A is a CMOS mixed signal Analog/Digital integrated circuit, which
performs three phase power/energy calculations over a range of 1000:1, to an overall
accuracy of better than Class 1.
The SA9605A in both DIP-20 and SOIC-20 package options is functionally similar to the
SA9105E and SA9105F with the advantage of no external loop capacitors.
The integrated circuit includes all the required functions for 3-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.
The SA9605A generates pulses, the frequency of which is proportional to the power
consumption. Two frequency outputs (FOUT1 and FOUT2) are available. The pulse rate
follows the instantaneous power measured.
4/14
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SA9605A
1.
Power Calculation
In the Application Circuit (Figure 1), the mains voltages from Line 1, Line 2 and Line
3, are converted to currents and applied to the voltage sense inputs IVN1, IVN2 and
IVN3.
The current levels on the voltage sense inputs are derived from the mains voltage
(3 x 230 VAC) being divided down through voltage dividers to 14V. The resulting
input currents into the A/D converters are 14µA through the resistors R15, R16 and
R17.
For the current sense inputs the voltage drop across the current transformers
terminating resistors are converted to currents of 16µA for rated conditions, by
means of resistors R8, R9 (Phase 1); R10, R11 (Phase 2); and R 12, R13 (Phase 3).
The signals providing the current information are applied to the current sensor
inputs: IIN1, IIP1; IIN2, IIP2; and IIN3, IIP3.
In this configuration, with the mains voltage of 3 x 230 V and rated currents of 80A,
the output frequency of the SA9605A energy metering integrated circuit at FOUT1
is 1.16kHz. In this case 1 pulse will correspond to an energy consumption of 3 x 18.4
kW/1160Hz = 47.6 Ws.
The output frequency at FOUT1 and FOUT2 represents the absolute sum of the
energy measured on all three phases, regardless of the direction of energy flow
through the current sensors. This measurement method will assist meter
manufacturers to circumvent meter tampering by reversal of the phases.
2.
Analog Input Configuration
The current and voltage sensor inputs are illustrated below.
These inputs are protected against electrostatic discharge through clamping
diodes, in conjunction with the amplifiers input configuration.
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 processing circuitry.
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5/14
SA9605A
VD D
IIP
CURRENT
SENSOR
INPUTS
VSS
A
I
VD D
IIN
VSS
VD D
IVN
VOLTAGE
SENSOR
INPUT
VSS
AV
GND
DR-01111
3.
4.
5.
6/14
Electrostatic Discharge (ESD) Protection
The SA9605A integrated circuit's inputs/outputs are protected against ESD.
Power Consumption
The overall power consumption rating of the SA9605A integrated circuit is less than
75mW with a 5V supply.
Pulse Output Signals
Waveforms displaying the DIR and FOUT1 signal information for each of the
three phases are shown below.
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SA9605A
8.94 µ s
DIR
71.55 µ s
8.94 µ s
PHASE 1,
POSITIVE
FOUT1
PHASE 1,
NEGATIVE
DIR
FOUT1
DIR
PHASE 2,
POSITIVE
FOUT1
DIR
PHASE 2,
NEGATIVE
FOUT1
DIR
PHASE 3,
POSITIVE
FOUT1
DIR
PHASE 3,
NEGATIVE
FOUT1
DR-01145
These waveforms demonstrate how to establish the direction of energy flow as well
as the phase from which the energy is measured. The direction of energy indicated
on pin DIR is HIGH for POSITIVE energy flow and LOW for NEGATIVE energy flow,
for the entire LOW period of the FOUT1 pulse. The phase to which the direction
indication on the DIR pin refers can be ascertained by counting the number of falling
edges on the DIR pin prior to the falling edge of the FOUT1 pulse. The supervision
of the DIR pin can be accomplished with a µController.
Although FOUT1 has a fixed frequency output, the table below shows the various
frequencies selectable for rated conditions on FOUT2.
User Selectable Output Frequency
FOUT2
PGM1
PGM0
(Hz)
0
0
5.11
0
1
3.83
1
0
2.55
1
1
N/A
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SA9605A
The frequencies shown in the above table were chosen to allow a 4 - 3 - 2 scaling ratio
for rated conditions. This facility provides ease of interface with applications which use
the same post divider with mechanical counter or unchanged microcontroller software
for different current rated kWh meters.
For example, a meter manufacturer may wish to build meters for 3 system configurations
with rated current loading of 80ARMS, 60ARMS and 40ARMS. The rated line voltage is
230VRMS.
FOUT1 Frequency
Consider the case where FOUT1 is the output of the energy counting block. For each
of the three rated conditions, the input current sensing resistors are chosen to ensure that
16µARMS flows into the current sensing pins.
Case 1
IL = 80A RMS
1 pulse on FOUT1 =
Case 2
IL = 60A RMS
1 pulse on FOUT1 =
Case 3
80 * 230 * 3
= 47.6Ws
1160
60 * 230 * 3
= 35.7Ws
1160
IL = 40A RMS
1 pulse on FOUT1 =
40 * 230 * 3
= 23.8Ws
1160
The amount of energy represented by one pulse for each of the three cases is different.
In addition to changing the current sensing resistor network, the energy counting block
must also be altered.
FOUT2 Frequency
Now consider the advantage of the user selectable frequency available on FOUT2.
Again the input current sensing resistors must be chosen to ensure that 16µARMS flows
into the current sensing pins.
Case 1
PGM1 = 0 PGM0 = 0
80 * 230 * 3
1 pulse on FOUT2 =
= 10.8kWs
5.11
Case 2
IL = 60ARMS,
Case 3
IL = 40ARMS,
8/14
IL = 80ARMS,
PGM1 = 0 PGM0 = 1
60 * 230 * 3
1 pulse on FOUT2 =
= 10.8kWs
3.83
PGM1 = 1 PGM0 = 0
40 * 230 * 3
1 pulse on FOUT2 =
= 10.8kWs
2.55
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SA9605A
The only changes which now have to be implemented to interface the device to different
rated systems are: change the current sense resistors; and select the required PGM0
and PGM1.
No change to the post divider or micro-controller software is required if the FOUT2 pin
is used as described.
TYPICAL APPLICATION
In the Application Circuit (Figure 1), the components required for a three phase power
metering application are shown.
Terminated current sensors (current transformers) are connected to the current sensor
inputs of the SA9605A through current setting resistors (R 8 ..R 13).
The resistor values for standard operation are selected for an input current of 16µA into
the SA9605A, at the rated line current.
The values of these resistors are calculated as follows:
Phase 1:
R8 = R9 = (IL1/16µA) * R18/2
Phase 2:
R10 = R11 = (IL2/16µA) * R19/2
Phase 3:
R12 = R13 = (IL3/16µA) * R20/2
Where ILX
= Secondary CT current at rated conditions.
R18, R19 and R20
= Current transformer termination resistors for the three phases.
R1 + R1A, R4 and R15 set the current for the phase 1 voltage sense input. R2 + R2A, R5 +
P5 and R16 set the current for phase 2 and R 3 + R3A, R6 + P6 and R17 set the current for phase
3. The values should be selected so that the input currents into the voltage sense inputs
(virtual ground) are set to 14µA for rated line voltage. Capacitors C1, C2 and C3 are for
decoupling and phase compensation.
R14 + P14 defines all on-chip bias and reference currents. With R14+ P14 = 24kΩ, optimum
conditions are set. R14 + P14 may be varied within ± 10% for calibration purposes. Any
changes to R14 + P14 will affect the output quadratically (i.e: ∆R = +5%, ∆f = +10%).
The formula for calculating the Output Frequency (f) is given below:
FOSC
(II1 I V1) + (II2 IV2) + (I I3 I V3)
f = 11.16 * FOUTX *
*
3.5795MHz
3 * IR 2
Where FOUTX = Nominal rated frequency (1160Hz)
FOSC
= Oscillator frequency (2MHz ...... 4MHz)
II1, II2, II3 = Input currents for current inputs (16µA at rated)
IV1, IV2 , IV3 = Input currents for voltage inputs (14µA at rated)
IR
= Reference current (typically 50µA)
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9/14
SA9605A
XTAL is a colour burst TV crystal (f = 3.5795 MHz) for the oscillator. The oscillator
frequency is divided down to 1.78975 MHz on-chip, to supply the digital circuitry and the
A/D converters.
Figure 1: Application Circuit for Three Phase Power/Energy Measurement.
MAINS VOLTAGES
LINE 1
LINE 2
LINE 3
R1
R1A
R2
R2A
R3
R3A
R11
R19
R10
VI2P
C3
VI2N
R17
1
20
2
19
3
R13 4
R12
R20
VI3P
5
VI3N
SA9605A
DIP - 20
FOUT1
FOUT2
R6
C2
R18
R8
VI1P
R9
18
6
7
R16
R15
17
C1
R4
15
IC-1
R5
R14
14
8
13
PGM1
9
12
PGM0
10
11
DIR
VI1N
16
P5
5V
R7
P14
0V
P6
XTAL
0V
C13
C12
0V
DR-01112
10/14
sames
0V
R21
C14
0V
SA9605A
Parts List for Application Circuit: Figure 1
Item
Symbol
Description
1
IC-1
Integrated SA9605A
2
XTAL
Crystal, 3.5795 MHz
3
R1
Resistor, 200k, 1%, ¼W
4
R1A
Resistor, 180k, 1%, ¼W
5
R2
Resistor, 200k, 1%, ¼W
6
R2A
Resistor, 200k, 1%, ¼W
7
R3
Resistor, 200k, 1% , ¼W
8
R3A
Resistor, 180k, 1%, ¼W
9
R4
Resistor, 24k, 1%, ¼W
10
R5
Resistor, 22k, 1%, ¼W
11
R6
Resistor, 22k, 1%, ¼W
12
R7
Resistor, 820Ω, 1%, ¼W
13
R8
Resistor
14
R9
Resistor
15
R10
Resistor
16
R11
Resistor
17
R12
Resistor
18
R13
Resistor
19
R14
Resistor, 22k, 1%, ¼W
20
R15
Resistor, 1M, 1%, ¼W
21
R16
Resistor, 1M, 1%, ¼W
22
R17
Resistor, 1M, 1%, ¼W
23
R18
Resistor
24
R19
Resistor
25
R20
Resistor
26
R21
Resistor, 820Ω, 1%, ¼W
27
P5
Potentiometer, 4.7k
28
P6
Potentiometer, 4.7k
29
P14
Potentiometer, 4.7k
30
C1
Capacitor, electrolytic, 1µF, 6V
31
C2
Capacitor, electrolytic, 1µF, 6V
32
C3
Capacitor, electrolytic, 1µF, 6V
33
C12
Capacitor, 820nF
34
C13
Capacitor, 100nF
35
C14
Capacitor, 100nF
sames
Detail
DIP-20, SOIC-20
Colour burst TV
Note 1
Note 1
Note 1
Note 1
Note 1
Note 1
Note 1
Note 1
Note 1
Multi turn
Multi turn
Multi turn
Note 2
Note 2
Note 2
Note 3
11/14
SA9605A
Note 1: Resistor (R8, R9, R10, R11, R12 and R13) values are dependant upon the selected
values of the current transformer termination resistors R18, R19 and R20.
Note 2:
Capacitor values may be selected to compensate for phase errors caused by
the current transformers.
Note 3: Capacitor (C12) to be positioned as close to Supply Pins (VDD & VSS ) of IC-1,
as possible.
ORDERING INFORMATION
Part Number
Package
SA9605APA
DIP-20
SA9605ASA
SOIC-20
12/14
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SA9605A
NOTES:
sames
13/14
SA9605A
Disclaimer:
The information contained in this document is confidential and proprietary to South African MicroElectronic 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 (Pty) Ltd
P O Box 15888,
33 Eland Street,
Lynn East,
Koedoespoort Industrial Area,
0039
Pretoria,
Republic of South Africa,
Republic of South Africa
Tel:
Fax:
14/14
012 333-6021
012 333-8071
sames
Tel:
Fax:
Int +27 12 333-6021
Int +27 12 333-8071