AN2317
Application Note
STPM01 Programmable, Single-Phase
Energy Metering IC External Circuits
Introduction
The STPM01 is implemented in an advanced 0.35µm BCD6 technology. It is designed for
active, reactive, and apparent energy measurement, including Root Mean Square (V
RMS
and I
RMS
), instantaneous, and harmonic voltage and current.
This application note describes the STPM01 external circuits which are comprised of:
●
●
●
●
a crystal oscillator,
a power supply circuit,
a voltage sensing circuit, and
two current sensing circuits.
Note:
This document should be used in conjunction with the STPM01 datasheet.
April 2006
Rev 1
1/27
www.st.com
Contents
AN2317 - Application
Contents
1
External Circuit Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1
Current Sensing Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.1
1.1.2
Primary Current Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Secondary current sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.2
1.3
1.4
1.5
Anti-aliasing Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Voltage Sensing Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Crosstalk Cancellation Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Capacitive Power Supply Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.5.1
1.5.2
1.5.3
Varistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Capacitive Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
EMC Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
1.6
Clock Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2/27
AN2317 - Application
List of Figures
List of Figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
STPM01 External Circuit Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Primary Current Sensing Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Current Sense Transformer-to-Power Line Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Shunt Module-to-Power Line Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Anti-aliasing Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Anti-aliasing Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Anti-aliasing Filter Magnitude Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Anti-aliasing Filter Phase Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Voltage Sensing Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Crosstalk Network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Capacitive power supply (with EMC Filter) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Capacitive Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Internal RC Recommended Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Quartz Recommended Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
External Clock Source Recommended Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3/27
External Circuit Design
AN2317 - Application
1
External Circuit Design
Figure 1 on page 5
shows an implementation example of the STPM01 in a simple Stepper
Counter Connector design. The main external circuits include:
●
●
●
●
●
a
Current Sensing Circuit,
an
Anti-aliasing Filter on page 11,
a
Voltage Sensing Circuit on page 15,
a
Capacitive Power Supply Circuit on page 18,
and
a
Clock Generation on page 24
(RC oscillator, quartz, or external clock).
4/27
AN2317 - Application
Figure 1.
1
33.0R
R21
R22
External Circuit Design
STPM01 External Circuit Schematics
2
1
C16
1K
1
1MY
W6
VODNIK
1
W5
VODNIK
1
VDD
D6
SRD 200mcd
D7 SRD 200mcd
D8 SRD 200mcd
1
2
2
D9 SRD 200mcd
2
D2
1N4148
C17
1
2
D3
1
2
D4
1
2
D5
1
1
1N4148
C18
10N
1
1N4148
C19
10N
1
1N4148
10N
2
1
3
5
2
1
2
Q3
BC8578
3
2
2
1
Q4
BC8578
31
R23
2
47K
2
2
2
PI
G08 10-2V
2
4
6
8
10
VDDA
7
9
1
1.0N
C3
C2
1
1.0N
C6
2
1MY
C7
2
1MY
C4
1
1.0N
C5
2
1MY
2
1
2.4K
1
1
R19
1
1
R18
1
1
2.4K
2
R17
2.4K
2
2
1N4148
1
2
1
2
1
2
20
U1
STPM01E
1
2
4
5
6
LED
MON
MOP
VDD
VCC
VDDA
VOIP
IIP1
IIN1
SDA
SCL
SCS
SYN
CLKIN
VIN
VIP
IIN2
IIP2
19
18
3
15
17
16
14
13
12
11
2
2
2.4K
R20
1
VDD
SBG
SDA
SCL
SCS
SYN
D1
VSS CLKOUT
VDDA
8
7
9
10
1
R15
2
1M
Y1
1
E4622/X503
4
TR1
1
R5
1
30.1R
R2
1.0k
2
1
10N
C8
2
1
1
4194.304kHz
1
C12
15P
1
2M
15P
2
R13
2
C13
21
R1
1.0k
2
2
2
ANTI-ALIASING FILTER
1
E4622/X503
4
TR2
1
R6
1
30.1R
R3
1.0k
C9
2
1
10N
1
R14
2
2M
CRYSTAL OR RTC
OSCILLATOR
21
R4
1.0k
2
2
C11
4.7my
C10
10N
2
1
R12
2
2.21k
CURRENT SENSING
1
2
1
2
VOLTAGE SENSING
1
R8
261K
2
1
R9
261K
2
1
R10
2
261K
1
R7
475R
1
R11
2
150K
C20
220N
C1
470N
D10
1
W3
VODNIK
1
2
VDD
1
1
1000M
D12
C15
+
1
5.6V
W2
VODNIK
1
1
W1
VODNIK
F
1
510V
1
L6
2
1
1
R24
2
82R
1.0N
1
2
2
1
DIF60
D11
DIF60
CAPACITIVE POWER SUPPLY
220MYH
C14
L3
W4
VODNIK
1
V4
2
N
1
2
2
2
2
2
220MYH
AI12296
5/27