STPM11ATR STMicroelectronics, STPM11ATR Datasheet - Page 35

• Manufacturer Part Number: STPM11ATR
• Description: IC ENERGY METER 1 PHASE 20TSSOP
• Manufacturer: STMicroelectronics

Specifications of STPM11ATR

• Input Impedance: 100 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 1.5V
• Voltage - I/o Low: 0.8V
• Current - Supply: 4.7mA
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP
• Meter Type: Single Phase
• Output Voltage: +/- 0.4 V
• Output Current: 150 mA
• Input Voltage: 3 V to 5.5 V
• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-5984-2

STPM11, STPM12, STPM13, STPM14
In the STPM1x, after the pre-conditioning and the A/D conversion, the digital voltage signal
(which is dynamically more stable with respect to the current signal) is processed by a
differentiate stage which transforms:
Equation 9
v(t) → v’(t) = dv/dt = V
The result, together with the pre-processed and digitalized current signal:
Equation 10
i(t) = I
can then be used to calculate. These digital signals are also used in two additional steps for
integration, obtaining:
Equation 11
dv/dt → v(t) = V
Equation 12
(see [8] in
Now four signals are available. Combining (pairing) them by two multiplication steps two
results are obtained:
Equation 13
(see [9] in
Equation 14
(see [10] in
After these two operations, another stage another step involves the subtraction of p1 from
p2 and dividing the result by 2, to obtain the active power:
Equation 15
(see [12] in
In this way, the AC part
p
p
p
/
/
1
2
) t (
) t (
) t (
=
=
=
⋅
p (
sin (tω + ϕ); (see [6] in
dv
dt
v
/
) t (
2
Figure
Figure
) t (
⋅
Figure
Figure
∫
⋅
i
) t (
i
2
−
) t (
⋅
p
/
=
sin tω; (see [7] in
22)
22)
⋅
1
dt
22)
22)
(
V
)) t
=
⋅ ⋅
i(t)
⋅
I
=
−
ω
2
cos
⋅
V
V
⋅
I
cos tω; (see [5] in
) t (
⋅ ⋅
⋅ ⋅
I
I
ϕ
Doc ID 13167 Rev 7
2
Figure
=
cos
2
cos
−
∫
V
i
Figure
) t (
ϕ
ϕ
⋅ ⋅
I
−
22)
⋅
dt
cos(
V
22)
=
⋅ ⋅
2
I
−
2
cos(
Figure
ω
ω
I
t
⋅
2
+
cos(
2
ϕ
ω
)
22);
t
ω
+
t
ϕ
+
)
ϕ
Energy calculation algorithm
)
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