sames
SA9122E
SINGLE PHASE UNIDIRECTIONAL POWER/ENERGY
METERING IC WITH SEPERATE 64 SEGMENT LCD DRIVER
FEATURES
n
Performs unidirectional power and
energy measurement
n
Adaptable to different types of current
sensors
n
On-chip 64 segment LCD driver
Meets the IEC 521/1036 Specification
requirements for Class 1 AC Watt hour
meters
n
Operates over a wide temperature
range
n
Total power consumption rating below
25 mW
n
Different pulse rate options available
for power information
LCD data input via a serial interface
n
n
DESCRIPTION
The SAMES SA9122E Single Phase
unidirectional active Power/Energy metering
integrated circuit includes a seperate onchip 64 segment Liquid Crystal Display driver.
The power/energy metering circuit generates
a pulse rate output, proportional to the power
consumption, while the LCD driver is
programmable via a serial interface.
The method of power calculation takes the
power factor into account. Energy consumption is determined by the power measurement
being integrated over time.
The LCD driver is capable of driving 8 decimal
digits (7 segment) and 8 announciators on a
4 track multiplexed backplane display.
This innovative combination energy metering/
LCD display driver integrated circuit has
been designed to provide meter designers
with flexibility in the choice of the µ-controller
employed, and is ideally suited for applications such as residential municipal metering
and factory energy metering and control.
The SA9122E integrated circuit is available
in both 40 pin dual-in-line plastic (DIP-40), as
well as 44 pin plastic leaded chip carrier
(PLCC-44) package types.
4362
PIN CONNECTIONS
RX
V SS
1
40 FOUT2
2
39 FOUT1
CIP
CIN
3
38 OSC1
4
37 OSC2
COP
5
36 S[15]
CON
IVN
6
35 S[14]
7
34 S[13]
IIP
8
33 S[12]
IIN
GND
VREF
9
32 S[11]
10
31 S[10]
11
30 S[9]
CPON
12
29 S[8]
CPOP
CPIN
13
28 S[7]
14
27 S[6]
CPIP
V DD
15
26 S[5]
16
25 S[4]
R[0]
R[1]
R[2]
17
24 S[3]
18
23 S[2]
19
22 S[1]
R[3]
20
21 S[0]
DR-00932
Package: DIP-40
1/12
PDS039-SA9122E-001
REV. A
19-09-1995
S[14]
S[13]
S[12]
S[11]
S[10]
N.C.
S[9]
S[8]
S[7]
S[6]
S[5]
SA9122E
39
37
36
35
34
33
32
31
30
29
40
28
41
27
42
26
43
25
44
24
1
23
2
22
3
21
4
20
5
19
6
18
DR-00934
8
9
10
11
12
CON
IVN
IIP
IIN
GND
N.C.
7
13
14
15
16
S[4]
S[3]
S[2]
S[1]
S[0]
N.C.
R[3]
R[2]
R[1]
R[0]
VD D
17
VREF
CPON
CPOP
CPIN
CPIP
S[15]
OSC2
OSC1
FOUT1
FOUT2
N.C.
RX
VS S
CIP
CIN
COP
38
Package: PLCC-44
BLOCK DIAGRAM
V DD
V SS
IIP
POWER
IIN
POWER
TO
FREQUENCY
INTEG-
ANALOG
FOUT1
FOUT2
RATOR
SIGNAL
S[15]
SRAM
PROCE-
SEGMENT
DRIVERS
S[0]
VOLTAGE
REF.
SSING
IVP
R[3]
GND
OSC
DR-00933
2/12
SERIAL
INTERFACE
VREF
sames
OSC1
OSC2
RX
BACKPLANE
DRIVERS
R[0]
SA9122E
ABSOLUTE MAXIMUM RATINGS*
Parameter
Symbol
Supply Voltage
VDD -VSS
Current on any pin
IPIN
Storage Temperature
TSTG
Operating Temperature
TO
Min
-0.3
-150
-40
-40
Max
6.0
+150
+125
+85
Unit
V
mA
°C
°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.
ELECTRICAL CHARACTERISTICS
(VDD = 2.5V, VSS = -2.5V, over the temperature range -10°C to +70°C#, unless otherwise
specified.)
Parameter
Symbol Min
Typ
Max
Unit Condition
Supply Voltage: Positive
VDD
2.25
2.75
V
Supply Voltage: Negative
VSS
-2.75
-2.25
V
Supply Current: Positive
IDD
5
7
mA
Supply Current: Negative
ISS
5
7
mA
-25
+25
µA
Peak value
IIV
-25
+25
µA
Peak value
VOL
VOH
VSS+1
VDD-1
V
V
IOL = 5mA
IOH = -2mA
1160
3000
Hz
Hz
Specified linearity
Min and max limits
Current Sensor Inputs (Differential)
Input Current Range
III
Voltage Sensor Input (Asymmetrical)
Input Current Range
Pins FOUT1, FOUT2
Output Low Voltage
Output High Voltage
Pulse Rate FOUT1
FOUT21
sames
fP
fP2
10
0.5
fP/290
3/12
SA9122E
ELECTRICAL CHARACTERISTICS (Continued)
Parameter
Symbol Min
Typ
Max Unit Condition
Oscillator
Recommended crystal:
TV colour burst crystal f = 3.5795 MHz
Pin VREF
Ref. Current
Ref. Voltage
-IR
VR
LCD backplane Voltage
VB
LCD segment Voltage
Note1:
#
Vs
45
1.1
50
55
1.3
VDD &
VSS
1/3 VDD
2/3 VDD
µA
V
V
V
With R = 24kΩ
connected to VSS
Referred to VSS
R[0] ... R[3]
S[0] ... S[15]
Two additional bondout options at FOUT2 are available on request: fp/4 and
fp/16.
Extended Operating Temperature Range available on request.
PIN DESCRIPTION
PLCC-44
11
18
3
8
10
9
42
41
14
15
16
17
4
5
6
7
13
2
44
43
4/12
DIP-40 Designation
10
GND
16
VDD
2
VSS
7
IVN
9
IIN
8
IIP
38
OSC1
37
OSC2
12
CPON
13
CPOP
14
CPIN
15
CPIP
3
CIP
4
CIN
5
COP
6
CON
11
VREF
1
RX
40
FOUT2
39
FOUT1
sames
Description
Ground
Positive Supply Voltage
Negative Supply Voltage
Analog input for Voltage
Inputs for current sensor
Connections for crystal or ceramic resonator
(OSC1 = Input ; OSC2 = Output)
Connections for outer loop capacitor of
A/D converter (Voltage)
Connections for inner loop capacitor of
A/D converter (Voltage)
Connections for inner loop capacitor of
A/D converter (Current)
Connections for outer loop capacitor of
A/D converter (Current)
Connection for current setting resistor
Serial data input
Pulse rate outputs
SA9122E
PIN DESCRIPTION (Continued)
PLCC-44
19
20
21
22
24
25
26
27
28
29
30
31
32
33
35
36
37
38
39
40
1
12
23
34
DIP-40 Designation
17
R[0]
18
R[1]
19
R[2]
20
R[3]
21
S[0]
22
S[1]
23
S[2]
24
S[3]
25
S[4]
26
S[5]
27
S[6]
28
S[7]
29
S[8]
30
S[9]
31
S[10]
32
S[11]
33
S[12]
34
S[13]
35
S[14]
36
S[15]
NC
NC
NC
NC
Description
Output drivers for LCD back planes
Output drivers for LCD segments
Not connected
FUNCTIONAL DESCRIPTION
The SA9122E 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, and includes a seperate 64 segment LCD display driver function.
The integrated circuit includes 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 SA9122E generates pulses, the
frequency of which is proportional to the power consumption. Two frequency outputs
(FOUT1 and FOUT2) are available, with additional frequency options available on
request. The pulse rate follows the instantaneous power measured.
The separate Liquid Crystal Display driver function included on-chip, drives up to 64
segments on a 4 track muliplexed backplane display, programmable via a serial interface
having a RS232 protocol.
sames
5/12
SA9122E
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 sensor input, the mains voltage (230VAC) is divided down through
a divider to 14V. The current into the A/D converter input is set at 14µARMS at nominal
mains voltage, via resistor R4 (1MΩ).
In this configuration, with a mains voltage of 230V and a current of 80A, the output
frequency of the SA9122E power meter chip at FOUT1 is 1.16kHz. In this case, 1
pulse will correspond to an energy consumption of 18.4kW/1160Hz = 15.9Ws.
The output frequency at FOUT2 is FOUT1 /290 (i.e. The frequency ouput at FOUT1
divided by 290).
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 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
IIN
CURRENT
SENSOR
INPUTS
V SS
AI
V DD
IIP
V SS
VDD
IVN
VOLTAGE
SENSOR
INPUT
DR-00935
6/12
sames
V SS
A
GND
V
SA9122E
3.
LCD Programming Protocol
Programming of the SA9122E's on-chip Liquid Crystal Display memory is performed
via a serial interface having a RS232 data format. The data for display is transferred
on RX at 19 200 baud.
The format of the data as well as the data memory map, is given below:
Data format on RX
START
A0
A1
A2
A3
D0
D1
D2
D3
STOP
DR-00937
LCD memory map
Inserting a '1' into a memory location turns the segment on and a '0' turns the
segment off.
A3
A2
A1
A0
D3
D2
D1
D0
Pin
0
0
0
0
S[0]
0
0
0
1
S[1]
0
0
1
0
S[2]
0
0
1
1
S[3]
0
1
0
0
S[4]
0
1
0
1
S[5]
0
1
1
0
S[6]
0
1
1
1
S[7]
1
0
0
0
S[8]
1
0
0
1
S[9]
1
0
1
0
S[10]
1
0
1
1
S[11]
1
1
0
0
S[12]
1
1
0
1
S[13]
1
1
1
0
S[14]
1
1
1
1
S[15]
R[3]
R[2]
R[1]
R[0]
sames
7/12
SA9122E
4.
5.
Electrostatic Discharge (ESD) Protection
The SA9122E integrated circuit's inputs/outputs are protected against ESD according
to Mil-Std 883C, method 3015.
Power Consumption
The power consumption rating of the SA9122E integrated circuit is less than 25mW.
TYPICAL APPLICATIONS
In the Application Circuit (Figure 1), the components required for this power metering
application, 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.
The most important external components for the SA9122E 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.
R2, R1 and RSH are the resistors defining the current level into the current sense input.
The values should be selected for an input current of 16µARMS into the SA9122E at
maximum line current.
Values for RSH of less than 200µΩ should be avoided.
R1 = R2 = (IL/16µARMS) * RSH/2
= Line current
Where IL
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 14µARMS.
R7 defines the reference current (IR). With R7 = 24kΩ, optimum conditions are set. R7
may be varied within ±10% for calibration purposes. Any change to R7 will affect the
output quadratically (i.e.: R7 = +5%, fP = +10%).
8/12
sames
SA9122E
The formula for calculating the output frequency is given below:
f = 11.16 * FOUTX *
Where FOUTX
FOSC
3.58MHz
*
II .IV
IR2
= Normal rated frequency (4Hz or 1160Hz)
FOSC
= Oscillator frequency (2MHz ...... 4MHz)
II
= Input current for current sensor input (16µA at rated line current)
IV
= Input current for voltage sensor input (14µA at rated line voltage)
IR
= Reference current (typically 50µA)
XTAL is a colour burst TV crystal (f = 3.5795 MHz) for the oscillator. The oscillator
frequency is divided down to 1.7897 MHz on-chip, to supply the digital circuitry and the
A/D converters.
sames
9/12
sames
RSH
SUPPLY
-2.5V
+2.5
R8
R9
10/12
R3
C6
C5
C7
R6
R2
R1
R4
R7
LOAD
C3
C1
C2
C4
36
35
34
33
5
6
7
8
27
26
14
15
22
19
21
23
18
20
24
17
25
28
13
16
29
30
31
12
11
10
IC-1
37
4
32
38
3
SA9122E
39
2
9
40
1
DR-00936
V DD
V SS
XTAL
FOUT1
FOUT2
RX
.
.
.
.
.
.
TO MICROCONTROLLER
.
FROM MICROCONTROLLER
.
.
.
.
.
.
.
.
.
LCD
R0
R1
R2
R3
SA9122E
Figure 1: Application Circuit using a Shunt Resistor for Current Sensing.
SA9122E
Parts List for Application Circuit: Figure 1
Item Symbol
Description
1
2
3
4
5
6
7
8
9
10
11
12
IC-1
XTAL
R1
R2
R3
R4
R6
R7
R8
R9
C1
C2
SA9122E
Crystal, 3.5795MHz
Resistor, 1% metal
Resistor, 1% metal
Resistor, 390k, (230VAC) 1%, metal
Resistor, 1M, 1/4W, 1%, metal
Resistor, 24k, 1/4W, 1%, metal
Resistor, 24k, 1/4W, 1%, metal
Resistor, 820Ω, 1/4W, 1%
Resistor, 820Ω, 1/4W, 1%
Capacitor, 560pF
Capacitor, 560pF
13
14
15
16
17
18
19
C3
C4
C5
C6
C7
LCD
RSH
Capacitor, 3.3nF
Capacitor, 3.3nF
Capacitor, 100nF
Capacitor, 100nF
Capacitor, 820nF
LCD 64 Segment, 4 back plane
Shunt Resistor
Detail
DIP-40/PLCC-44
Colour burst TV
Note 1
Note 1
Note 2
Note 3
Note 1: Resistor (R1 and R2) values are dependant upon the selected value of RSH.
Note 2: Capacitor (C7) to be positioned as close to Supply Pins (VDD & VSS) of IC-1 as
possible.
Note 3: See TYPICAL APPLICATIONS when selecting the value of RSH.
ORDERING INFORMATION
Part Number
Package
SA9122EPA
DIP-40
SA9122EFA
PLCC-44
sames
11/12
SA9122E
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, 0039
Koedoespoort Industrial Area,
Republic of South Africa,
Pretoria,
Republic of South Africa
Tel:
Fax:
12/12
012 333-6021
012 333-8071
sames
Tel:
Fax:
Int +27 12 333-6021
Int +27 12 333-8071