fs6611 Fortune Semiconductor Corporation, fs6611 Datasheet - Page 13

• Manufacturer Part Number: fs6611
• Description: Energy Metering Ic With Impulse Output
• Manufacturer: Fortune Semiconductor Corporation

Rev. 1.1
v(t) = V
Where:
and
i(t) = I
Where:
and
Using Equations (1) and (2), the real power P can be
expressed in terms of its fundamental real power (P
and harmonic real power (P
P = P
Where:
and:
As can be seen from Equation (4) above, a harmonic
real power component is generated for every
harmonic, provided that harmonic is present in both
the voltage and current waveforms. The power factor
calculation has previously been shown to be
accurate in the case of a pure sinusoid; therefore the
harmonic real power must also correctly account for
the power factor since it is made up of a series of
pure sinusoids.
Note:
The input bandwidth of the analog inputs is 14 kHz
with a master clock frequency of 3.579545MHz.
13.4 Analog Inputs
13.4.1
The voltage output from the current transducer is
connected to the FS6611 here. Channel V1 is a fully
differential voltage input. V1P is the positive input
with respect to V1N.
The maximum peak differential signal on Channel 1
should be less than ±470mV (330mV rms for a pure
sinusoidal signal) for specified operation. Note that
β
1
0
v(t) is the instantaneous voltage
V
V
α
i(t) is the instantaneous current
I
I
P
φ
P
Φ
+ P
0
h
h
+
h
0
0
h
1
1
h
h
is the phase angle of the current harmonic
is the dc component
is the rms value of current harmonic h
+
is the phase angle of the voltage harmonic
Channel V1 (Current Channel)
is the average value
is the rms value of voltage harmonic h
= V
=α
=
= α
h
2
∑
2
h
×
1
1
∞
≠1
×I
-β
×
h
∑
h
-β
∞
1
≠
∑
h
cosφ
0
∞
1
≠
V
I
0
h
h
V
h
×I
×sin(hωt +β
1
h
h
cosφ
×sin(hωt +α
h
h
).
h
)
h
)
(2)
(1)
(3)
(4)
1
)
Channel 1 has a programmable gain amplifier (PGA)
with user selectable gain of 1, 2, 8, or 16 (see Table
I). These gains facilitate easy transducer interfacing.
Fig7 illustrates the maximum signal levels on V1P
and V1N. The maximum differential voltage is
±470mV divided by the gain selection. The
differential voltage signal on the inputs must be
referenced to a common mode, e.g., AGND. The
maximum common mode signal is ±100 mV as
shown in Fig7.
Fig7 Maximum Signal Levels (Channel 1, Gain = 1)
13.4.2
The output of the line voltage transducer is
connected to the FS6611 at this analog input.
Channel V2 is a fully differential voltage input. The
maximum peak differential signal on Channel 2 is ±
660mV.
Fig8
Fig8 illustrates the maximum signal levels that can
be connected to the FS6611 Channel 2. Channel 2
must be driven from a common-mode voltage, i.e.,
the differential voltage signal on the input must be
referenced to a common mode (usually AGND). The
analog inputs of the FS6611 can be driven with
common-mode voltages of up to 100mV with respect
to AGND. However, best results are achieved using
a common mode equal to AGND.
+4 70 mV
-4 70 mV
G1 G0 Gain
+660mV
-660mV
0
0
1
1
VCM
VCM
V1
Table I
V2
Maximum Signal Levels (Channel 2)
0
1
0
1
Channel V2 (Voltage Channel)
32
16
1
8
Gain Selection for Channel 1
Diffe re ntial Inp ut
Differential Input
Commo n Mo de
±
±
±
Common Mode
±
4 70 mV Ma x
10 0mV Ma x
660mV Max
100mV Max
Differential Signal (mV)
AG ND
AG ND
Maximum
V1
V2
VCM
VCM
V2P
V2N
V1 P
V1 N
±470
±15
±60
±30
FS6611
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