sames
SA9103E
SINGLE PHASE BIDIRECTIONAL POWER/ENERGY
METERING IC WITH SERIAL INTERFACE
FEATURES
n
Performs bidirectional active power/
energy measurement
n
Operates over a wide temperature
range
n
Meets the IEC 521/1036 Specification
requirements for Class 1 AC Watt hour
meters
n
Serial interface having a RS232
protocol
n
n
Protected against ESD
n
Power consumption rating below 25mW
Precision voltage reference on-chip
Tri-state output to allow parallel
connection of devices.
n
Adaptable to different current sensor
technologies
DESCRIPTION
The SAMES SA9103E Single Phase
bidirectional Power/Energy metering
integrated circuit has a serial interface with
a RS232 protocol, ideal for use with a µController. The SA9103E performs the
calculation for active power.
The integrated value for active energy is
accessable through the RS232-Interface
as a 16 bit value.
This innovative universal single phase
power/energy metering integrated circuit
is ideally suited for energy calculations in
applications such as electricitydispensing
systems (ED's), residential municipal
metering and factory energy metering and
control.
The SA9103E integrated circuit is available
in both 20 pin dual-in-line plastic (DIP-20),
as well as 20 pin small outline (SOIC-20)
package types.
n
PIN CONNECTIONS
IIN
1
20 GND
IIP
2
19 IVP
VREF
3
18 CON
CPON
4
17 COP
CPOP
5
16 CIN
CPIN
6
15 CIP
CPIP
V DD
7
14
8
13 SIN
TP9
9
12 SOUT
OSC2
10
11 OSC1
V SS
DR-00917
Package: DIP-20
SOIC-20
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4353
PDS039-SA9103E-001
REV. B
14-11-1996
SA9103E
BLOCK DIAGRAM
V DD
IIP
IIN
SIN
SOUT
ACTIVE
ENERGY
ANALOG
V SS
SERIAL
INTERFACE
SIGNAL
PROCEVOLTAGE
REF.
SSING
IVP
GND
OSC
DR-00918
VREF
OSC1
TIMING
OSC2
ABSOLUTE MAXIMUM RATINGS*
Parameter
Supply Voltage
Symbol
VDD -VSS
Min
Max
Unit
-0.3
6.0
V
Current on any pin
IPIN
-150
+150
Storage Temperature
TSTG
-40
+125
°C
TO
-40
+85
°C
Operating Temperature
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 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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SA9103E
ELECTRICAL CHARACTERISTICS
(VDD = 2.5V, VSS = -2.5V, over the temperature range -10°C to +70°C#, unless otherwise
specified.)
Parameter
Symbol
Min
Supply Voltage: Positive
VDD
Supply Voltage: Negative
VSS
Supply Current: Positive
IDD
Supply Current: Negative
ISS
Typ
Max
Unit
Condition
2.25
2.75
V
-2.75
-2.25
V
5
6
mA
5
6
mA
-25
+25
µA
Peak value
+25
µA
Peak value
VSS+1
V
V
IOL = 5mA
IOH = -2mA
V
V
µA
VIN = V SS
Current Sensor Inputs (Differential)
Input Current Range
I II
Voltage Sensor Input (Asymetrical)
Input Current Range
I IV
-25
Pin SOUT
Output Low Voltage
Output High Voltage
V OL
VOH
VDD-1
Pin SIN
High Voltage
Low Voltage
Pull-up Current
VIH
VIL
-II
Oscillator
VSS+1
150
50
Recommended crystal:
TV colour burst crystal f = 3.5795 MHz
Pin VREF
Ref. Current
Ref. Voltage
#
VDD-1
-I R
VR
45
1.1
50
55
1.3
µA
V
With R = 24kΩ
connected to VSS
Referred to V SS
Extended Operating Temperature Range available on request.
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SA9103E
PIN DESCRIPTION
Pin
Designation
Description
20
8
GND
VDD
Ground
Positive Supply Voltage
14
VSS
Negative Supply Voltage
19
IVP
Analog input for Voltage
1
IIN
Inputs for current sensor
2
IIP
11
OSC1
Connections for crystal or ceramic resonator
10
OSC2
(OSC1 = Input ; OSC2 = Output)
12
SOUT
Serial Interface Out
13
SIN
Serial Interface In
4
CPON
Connections for outer loop capacitors of
5
CPOP
A/D converter (Voltage)
6
CPIN
Connections for inner loop capacitors of
7
CPIP
A/D converter (Voltage)
15
CIP
Connections for inner loop capacitors of
16
CIN
A/D converter (Current)
17
COP
Connections for outer loop capacitors of
18
CON
A/D converter (Current)
3
VREF
Connection for current setting resistor
9
TP9
Test Pin. Connect to VSS
FUNCTIONAL DESCRIPTION
The SA9103E is a CMOS mixed signal Analog/Digital integrated circuit, which performs
power/energy calculations across a power range of 1000:1, to an overall accurancy of
better than Class 1.
The integrated circuit includes of all the required functions for 1-phase 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 SA9103E integrates the measured
active power consumption into a 22 bit integrator, which is accessable via a serial port
having a RS232 protocol.
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SA9103E
1.
Power calculation
In the Application Circuit (Figure 1), the voltage drop across the shunt will be
between 0 and 16mV (0 to 80A through a shunt resistor of 200µΩ). This voltage is
converted to a current of between 0 and 16µA, by means of resistors R1 and R2.
The current sense input saturates at an input current of ±25µA peak.
For the voltage sense input, the mains voltage (230VAC) is divided down through
a divider to 14V. The resulting current into the A/D converter input is set at 14µA
at nominal mains voltage,via resistor R4 (1MΩ).
In this configuration, with a mains voltage of 230V and a current of 80A, the SA9103E
functions at its optimum conditions, having a margin of 3dB for overload available.
2.
Analog Input Configuration
The input circuitry of the current and voltage sensor inputs are illustrated below.
These inputs are protected against electrostatic discharge through clamping
diodes.
The feedback loops from the outputs of the amplifiers A I 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
V SS
AI
V DD
IIN
V SS
V DD
IVP
VOLTAGE
SENSOR
INPUT
DR-00919
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V SS
A
V
GND
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SA9103E
3.
Electrostatic Discharge (ESD) Protection
The SA9103E integrated circuit's inputs/outputs are protected against ESD.
4.
Power Consumption
The power consumption rating of the SA9103E integrated circuit is less than
25mW.
5.
Serial Interface
Reading and resetting of the SA9103E's on-chip integrator, is performed via the
serial interface.
The settings are:
19 200 Baud
1 Start bit (S)
1 Stop bit (E)
No parity bits
The Serial Interface allows for the following operations:
Read Integrator: The SA9103E integrated circuit transmits the integrator status
to the controller, after the current measurement cycle has been completed (8 mains
periods maximum).
Reset Integrator: The SA9103E integrator is reset, without transmitting the
integrator status.
Read/Reset Integrator): The SA9103E transmits the integrator status and resets
the integrator after the current measurement cycle has been completed.
In a typical application, the system controller monitors the status of the SA9103E's
integrator using the "Read" command. At rated load conditions, the capacity of the
22 bit integrator allows for an integration time of 2 seconds prior to integrator
overflow.
If after a "Read" command, the integrator value is sufficently high, a "Read/Reset"
command from the controller causes the SA9103E integrated circuit to complete
the existing measurement cycle, transmit the 16 most significant bits of the 22 bit
integrator via the Serial Output (SOUT) to the controller and restart the integrator.
In order to ensure correct measurements, the integrator commands ("Read" and
"Read/Reset") are only executed after completion of the internal offset calibration
cycle. The cycle length is 8 mains periods.
Thus, for power calculations, the time value should be taken from the difference in
time from the previously received energy value to the currently received value.
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SA9103E
By adapting the "Read/Reset" rate to the line current the accuracy of the measurement
can be achieved down to lowest signal levels.
Read, Reset and Read/Reset of integrator for active energy
RD
RD
RE S
RE S
RD
RD /
RE S
RE S
S T OP
BI T
ST AR T
BI T
D R -0 0 9 2 0
The register access codes which can be written to the SA9103E via the serial
communications port are shown in the table below:
REGISTER
Active
READ
$01
RESET
$02
READ-RESET
$03
From the two bytes of data output by the device, the value for the register may be
derived as shown:
Register value = (first byte * 256) + second byte
The most significant bit of the 16 bit energy register is an indication fo the direction
of the energy flow (0 = positive, 1 = negative)
Data on SOUT
8
9
10
11
12
FIRST BYTE
13
14
15
0
1
2
3
4
5
6
7
SECOND BYTE
DR-00923
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SA9103E
6.
Register Values
The active energy measured per count, may be calculated by applying the following
formula:
VI
K
Energy per Count =
When
V
I
K
=
=
=
Rated Voltage
Rated Current
9281 for Active Energy
TYPICAL APPLICATIONS
In the Application Circuits (Figures 1 and 2) the components required for power metering
applications, are shown.
In Figure 1, a shunt resistor is used for current sensing. In this application, the circuitry
requires a +2.5V, 0V, -2.5V DC supply.
In the case of Figure 2, when using a current transformer for current sensing, a +5V, 0V
DC supply is sufficient for the circuit.
The most important external components for the SA9103E integrated circuit are:
C1 and C2 are the outer loop capacitors for the two integrated oversampling A/D
converters. The value of these capacitors is 560pF. The actual values determine the
signal to noise and stability performance. The tolerances should be within ±10%.
C3 and C4 are the inner loop capacitors of the A/D converters. The optimum value is 3.3nF.
The actual values are uncritical. Values smaller than 0.5nF and larger than 5nF should
be avoided.
R1, R2 and RSH are the resistors defining the current level into the current sense input.
The values should be selected for an input current of 16µA into the SA9103E at maximum
line current.
Values for RSH of less than 200µΩ should be avoided.
R1 = R2 = (IL/16µA) * RSH/2
Where IL = Line current
RSH = Shunt resistor/termination resistor
R3, R6 and R4 set the current for the voltage sense input. The values should be selected
so that the input current into the voltage sense input (virtual ground) is set to 14µA.
R7 defines all on-chip bias and reference currents. With R7 = 24kΩ, optimum conditions
are set.
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SA9103E
XTAL is a colour burst TV crystal (f = 3.5795MHz) for the oscillator. The oscillator
frequency is divided down to 1.7897MHz on-chip, to supply the A/D converters and digital
circuitry.
Figure 1: Application Circuit using a Shunt Resistor for Current Sensing, having
a PC (Personal Computer) Interface.
Note: The Serial Interface having a RS232 protocol, has been designed to operate
directly with a PC (Personal Computer).
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SA9103E
Part List for Application Circuit: Figure 1
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
32
33
34
35
36
Symbol
IC-1
IC-2
IC-3
D1
D2
D3
ZD1
ZD2
XTAL
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
C1
C2
C3
C4
C9
C10
C11
C12
C13
C14
C15
RSH
Description
SA9103E
Opto Coupler 4N35
Opto Coupler 4N35
Diode, Silicon, 1N4148
Diode, Silicon, 1N4148
Diode, Silicon, 1N4148
Diode, Zener, 2.4V, 200mW
Diode, Zener, 2.4V, 200mW
Crystal, 3.5795MHz
Resistor, 1% metal
Resistor, 1% metal
Resistor, 390k, (230VAC), 1% metal
Resistor, 1M, 1/4W, 1% metal
Resitor, 470Ω, 2W, 5%, carbon
Resistor, 24k, 1/4W, 1%, metal
Resistor, 24k, 1/4W, 1%, metal
Resistor, 680Ω, 1/4W, 5%
Resistor, 680Ω, 1/4W, 5%
Resistor, 680Ω, 1/4W, 5%
Resistor, 100k, 1/4W, 5%
Resistor, 120Ω, 1/4W, 5%
Resistor, 120k, 1/4W, 5%
Resistor, 3.9k, 1/4W, 5%
Resistor, 120Ω, 1/4W, 5%
Capacitor, 560pF
Capacitor, 560pF
Capacitor, 3.3nF
Capacitor, 3.3nF
Capacitor, 100nF
Capacitor, 100nF
Capacitor, 0.47µF, 250VAC, polyester
Capacitor, 100nF
Capacitor, 100µF
Capacitor, 100µF
Capacitor, 820nF
Shunt Resistor
Detail
DIP-20/SOIC-20
DIP-6
DIP-6
Colour burst TV
Note 1
Note 1
Note 2
Note 1: Resistor (R1 and R2) values are dependant upon the selected value of RSH.
Note 2: See TYPICAL APPLICATIONS when selecting the value for RSH.
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SA9103E
Figure 2: Application Circuit using a Current Transformer for Current Sensing.
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SA9103E
Parts List for Application Circuit: Figure 2
Item
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Symbol
IC-1
XTAL
RSH
R1
R2
R3
R4
R6
R7
R8
R9
C1
C2
C3
C4
C9
C10
C11
CT
Description
SA9103E
Crystal, 3.5795MHz
Resistor
Resistor, 1%, metal
Resistor, 1%, metal
Resistor, 390k, (230VAC) 1%, metal
Resistor, 1M, 1/4W, metal
Resistor, 24k, 1/4W, metal
Resistor, 24k, 1/4W, metal
Resistor, 2.2k, 1/4W, 5%
Resistor, 2.2k, 1/4W, 5%
Capacitor, 560pF
Capacitor, 560pF
Capacitor, 3.3nF
Capacitor, 3.3nF,
Capacitor, 820nF
Capacitor, 100nF
Capacitor
Current transformer
Detail
DIP-20/SOIC-20
Colour burst TV
Note 1
Note 2
Note 2
Note 3
Note 4
Note 1: See TYPICAL APPLICATIONS when selecting the value of RSH.
Note 2: Resistor (R1and R2) values are dependant upon the selected value of
RSH.
Note 3: Capacitor (C9) to be positioned as close to IC-1, as possible.
Note 4: Capacitor (C11) selected for DC blocking and to minimize phase error
introduced by the current transformer.
ORDERING INFORMATION
Part Number
Package
SA9103EPA
SA9103ESA
DIP-20
SOIC-20
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SA9103E
NOTES:
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SA9103E
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 out 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
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Tel:
Fax:
Int +27 12 333-6021
Int +27 12 333-8071