FEATURES DESCRIPTION BLOCK DIAGRAM

BL6503 Single Phase Energy Meter IC
FEATURES
DESCRIPTION
High accuracy, less than 0.1% error over a
dynamic range of 500 : 1
The BL6503 is a low cost, high accuracy, high
stability, simple peripheral circuit electrical energy
Exactly measure the real power in the positive
meter IC. The meter based on the BL6503 is intended
orientation and negative orientation, calculate the
for using in single-phase, two-wire distribution
energy in the same orientation
systems.
A PGA in the current channel allows using small
value shunt and burden resistance
The BL6503 adopts the oversample technology
and digital signal processing technology. It can
The low frequency outputs F1 and F2 can
exactly measure the real power in the positive
directly drive electromechanical counters and two
orientation and negative orientation and calculate the
phase stepper motors and the high frequency output
energy in the same orientation. Moreover, BL6503
CF, supplies instantaneous real power, is intended for
supplies the negative orientation indication on Pin20
calibration and communications
(REVP). Therefore, the meter using the BL6503 has
The logic outputs REVP can be used to indicate a
great capability to avoid fault condition.
potential orientation
The BL6503 supplies average real power
Low static power (typical value of 15mW).
information on the low frequency outputs F1 (Pin23)
The technology of SLiM (Smart–Low–current–
and F2 (Pin24). These logic outputs may be used to
Management )
is used.
directly drive an electromechanical counter and
On-Chip power supply detector
two-phase stepper motors. The CF (Pin22) logic
On-Chip anti-creep protection
output gives instantaneous real power information.
On-Chip voltage reference of 2.42V ± 8%
This output is intended to be used for calibration
(typical temperature coefficient of 30ppm/℃),with
purposes or interface to an MCU.
external overdrive capability
The BL6503 adopts the technology of SLiM and
Single 5V supply
decreases greatly the static power. This technology
Credible work, working time is more than twenty
also decreases the request for power supply.
years
BL6503 thinks over the stability of reading
error in the process of calibration.. An internal no-load
Interrelated patents are pending
threshold ensures that the BL6503 does not exhibit
any creep when there is no load.
BLOCK DIAGRAM
DVDD
1
24
F1
AC/DC
2
23
F2
AVDD
3
22
CF
VREF
power detector
voltage
reference
NC
4
21
DGND
V1P
5
20
REVP
V1P
V1N
6
19
NC
V1N
V2N
7
V2P
RESET
BL6503
18
CLKOUT
8
17
CLKIN
9
16
G0
VREF 10
15
G1
AGND 11
14
S0
SCF 12
13
S1
AVDD
V2P
V2N
current
sampling
voltage
sampling
analog to
digital
analog to
digital
BL6503
high
pass
filter
digital
multiplication
high
pass
filter
digital to
frequency
and
output
low
pass
filter
REVP
CF
F1
F2
logical control
G0
G1
AC/DC
RESET
SCF
S0
S1
DIP/SSOP 24
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BL6503 Single Phase Energy Meter IC
PIN DESCRIPTIONS
Pin
Symbol
DESCRIPTIONS
Digital Power Supply (+5V). Provides the supply voltage for the digital circuitry. It
should be maintained at 5 V±5% for specified operation.
1
DVDD
2
AC/ DC
High-Pass Filter Select. This logic input is used to enable the high pass filter in the
current channel. Logic high on this pin enables the HPF.
3
AVDD
Analog Power Supply (+5V). Provides the supply voltage for the analog circuitry. It
should be maintained at 5 V±5% for specified operation.
4
NC
5,6
V1P,V1N
Inputs for Current Channel. These inputs are fully differential voltage inputs with a
maximum signal level of ±660 mV
7,8
V2N,V2P
Negative and Positive Inputs for Voltage Channel. These inputs provide a fully
differential input pair. The maximum differential input voltage is ±660 mV for
specified operation.
9
RESET
Reset Pin. Logic low on this pin will hold the ADCs and digital circuitry in a reset
condition and clear internal registers.
10
VREF
On-Chip Voltage Reference. The on-chip reference has a nominal value of 2.5V ±
8% and a typical temperature coefficient of 30ppm/℃. An external reference source
may also be connected at this pin.
11
AGND
Analog Ground Reference. Provides the ground reference for the analog circuitry.
12
SCF
Calibration Frequency Select. This logic input is used to select the frequency on the
calibration output CF.
13,14
S1,S0
Output Frequency Select. These logic inputs are used to select one of four possible
frequencies for the digital-to-frequency conversion. This offers the designer greater
flexibility when designing the energy meter.
15,16
G1,G0
Gain Select. These logic inputs are used to select one of four possible gains for current
channel. The possible gains are 1, 2, 8, and 16.
17
CLKIN
Clock In. An external clock can be provided at this logic input. Alternatively, a crystal
can be connected across this pin and pin18 (CLKOUT) to provide a clock source
18
CLKOUT
Clock Out. A crystal can be connected across this pin and pin17 (CLKIN) as described
above to provide a clock source.
19
NC
Reserved.
Reserved.
Negative Indication. Logic high indicates negative power, i.e., when the phase angle
20
REVP
between the voltage and current signals is greater that 90°. This output is not latched
and will be reset when positive power is once again detected.
21
DGND
Digital Ground Reference. Provides the ground reference for the digital circuitry.
22
CF
Calibration Frequency. The CF logic output gives instantaneous real power
information. This output is intended to use for calibration purposes.
23,24
F1,F2
Low-Frequency. F1 and F2 supply average real power information. The logic outputs
can be used to directly drive electromechanical counters and 2-phase stepper motors.
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BL6503 Single Phase Energy Meter IC
ABSOLUTE MAXIMUM RATINGS
( T = 25 ℃ )
Symbol
Value
Unit
Analog Power Voltage AVDD
AVDD
-0.3~+7(max)
V
Digital power Voltage DVDD
DVDD
-0.3~+7(max)
V
-0.3~+0.3
V
Parameter
DVDD to AVDD
Analog Input Voltage of Channel 2 to AGND
V (V)
VSS+0.5≤V(v)≤VDD-0.5
V
Analog Input Voltage of Channel 1 to AGND
V (I)
VSS+0.5≤V(i)≤VDD-0.5
V
Operating Temperature Range
Topr
-40~+85
℃
Storage Temperature Range
Tstr
-55~+150
℃
400
mW
Power Dissipation(DIP24)
Electronic Characteristic Parameter
(T=25℃, AVDD=5V, DVDD= 5V, CLKIN=3.58MHz
Parameter
Symbol
Test Condition
)
Measure
Pin
Min
Value
Typical
Value
Max
Value
Unit
1 Analog Power Current
IAVDD
Pin1
2
3
mA
2 Digital Power Current
IDVDD
Pin3
1
2
mA
3 Logic Input Pins
G0, G1, SCF,S0,S1,
ACDC, /RESET
Pin2,
9,12,
13,14,
15,16
Input High Voltage
VIH
Input Low Voltage
VIL
Input Capacitance
CIN
AVDD=5V
DVDD=5V
4 Logic Output Pins
F1, F2
VOH1
IH=10mA
Output Low Voltage
VOL1
IL=10mA
V
10
pF
V
0.5
10
V
mA
Pin22,
20,19
Output High Voltage
VOH2
IH=10mA
Output Low Voltage
VOL2
IL=10mA
6 On-chip Reference
Vref
AVDD=5V
7 Analog Input Pins
V1P, V1N
V2N, V2P
4
Pin10
2.3
V
2.6
0.5
V
2.8
V
±1
V
Pin 5,6,
7,8
VAIN
DC Input Impedance
330
Input Capacitance
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1
4.4
IO1
5 Logic Output Pins
CF, REVP,
Maximum Input Voltage
V
Pin23,
24
Output High Voltage
Output Current
2
Kohm
10
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BL6503 Single Phase Energy Meter IC
8 Accuracy
Measurement Error on
Channel 1 and 2
Gain=1
ENL1
Pin22
0.1
0.4
%
Gain=2
ENL2
Pin22
0.1
0.4
%
Pin22
0.1
0.4
%
Pin22
0.1
0.4
%
Channel 1 Lead 37°
(PF=0.8Capacitive)
Pin22
0.1
0.3
%
Channel 1 Lags
(PF=0.5Inductive)
Pin22
0.1
0.3
%
Gain=8
ENL8
Gain=16
ENL16
Phase Error
Channels
Both Channels with
Full-Scale Signal
±660mV
Over a Dynamic
Range500 to 1
between
9 Start Current
ISTART
Ib=5A C=3200,
Pin5
cosϕ=1
Voltage Channel
0.2%I
b
A
Inputs ±110mV
Gain of Current
Channel 16
10 Positive and Negative
Real Power Error (%)
ENP
Vv=±110mV,V(I)=
2mV, cosϕ=1
Vv=±110mV,V(I)=
2mV, cosϕ=-1
Pin22
0.4
%
11 Gain Error
Gain
error
External 2.5V
Reference,Gain=1,
V1=V2=500mV
DC
Pin22
±10
%
1
%
4.1
V
12 Gain Error Match
13Power Supply
Monitor Voltage
Vdown
Power Supply vary
from 3.5V to
5V,and Current
Channel with
Full-Scale Signal
Pin22
0.2
Pin22
3.9
4
TERMINOLOGY
1) Measurement Error
The error associated with the energy measurement made by the BL6503 is defined by the
following formula:
Pencentage Error =
Energy Re gistered by the BL6501 − True Energy
× 100%
True Energy
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BL6503 Single Phase Energy Meter IC
2) Nonlinear Error
The Nonlinear Error is defined by the following formula:
eNL%=[(Error at X-Error at Ib) / (1+Error at Ib )]*100%
When V(v)= ±110mV, cosϕ=1, over the arrange of 5%Ib to 800%Ib, the nonlinear error should be
less than 0.1%.
3) Positive and Negative Real Power Error
When the positive real power and the negative real power is equal, and V(v) =±110mV, the test
current is Ib, then the positive and negative real power error can be achieved by the following
formula:
eNP%=|[(eN%-eP%)/(1+eP%)]*100%|
Where: eP% is the Positive Real Power Error, eN% is the Negative Real Power Error.
4) Gain Error
The gain error of the BL6503 is defined as the difference between the measured output frequency
(minus the offset) and the ideal output frequency. It is measured with a gain of 1 in channel V1.
The difference is expressed as a percentage of the ideal frequency. The ideal frequency is obtained
from the BL6503 transfer function.
5) Gain Error Match
The gain error match is defined as the gain error (minus the offset) obtained when switching
between a gain of 1 and a gain of 2, 8, or 16. It is expressed as a percentage of the output
frequency obtained under a gain of 1. This gives the gain error observed when the gain selection is
changed from 1 to 2, 8 or 16.
6) Power Supply Monitor
BL6503 has the on-chip Power Supply monitoring The BL6503 will remain in a reset
condition until the supply voltage on AVDD reaches 4 V. If the supply falls below 4 V, the BL6503
will also be reset and no pulses will be issued on F1, F2 and CF.
TIMING CHARACTERISTIC
(AVDD=DVDD=5V, AGND=DGND=0V, On-Chip Reference, CLKIN=3.58MHz, Temperature
range: -40~+85°C)
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BL6503 Single Phase Energy Meter IC
Parameter
t1
Value
275ms
t2
Comments
F1 and F2 pulse-width (Logic Low). When the power is low, the
t1 is equal to 275ms; when the power is high, and the output
period exceeds 550ms, t1 equals to half of the output period.
F1 or F2 output pulse period.
t3
½ t2
Time between F1 falling edge and F2 falling edge.
t4
90ms
CF pulse-width (Logic high). When the power is low, the t4 is
equal to 90ms; when the power is high, and the output period
exceeds 180ms, t4 equals to half of the output period.
t5
CF Pulse Period. See Transfer Function section.
t6
CLKIN/4
Minimum Time Between F1 and F2.
Notes:
1) CF is not synchronous to F1 or F2 frequency outputs.
2) Sample tested during initial release and after any redesign or process changes that may affect
this parameter.
THEORY OF OPERATION
Principle of Energy Measure
In energy measure, the power information varying with time is calculated by a direct
multiplication of the voltage signal and the current signal. Assume that the current signal and the
voltage signal are cosine functions; Umax, Imax are the peak values of the voltage signal and the
current signal; ωis the angle frequency of the input signals; the phase difference between the
current signal and the voltage signal is expressed asφ. Then the power is given as follows:
p (t ) = U max cos( wt ) × I max cos( wt + ϕ )
If φ=0:
p (t ) =
U max I max
[1 + cos(2 wt )]
2
If φ≠0:
p (t ) = U max cos(ωt ) × I max cos(ωt + Φ )
= U max cos(ωt ) × [I max cos(ωt ) cos(Φ ) + I max sin(ωt ) sin(Φ )]
U max I max
[1 + cos(2ωt )] cos(Φ ) + U max I max cos(ωt ) sin(ωt ) sin(Φ )
2
U I
U I
= max max [1 + cos(2ωt )] cos(Φ ) + max max sin( 2ωt ) sin(Φ)
2
2
U I
U I
= max max cos(Φ) + max max [cos(2ωt ) cos(Φ ) + sin( 2ωt ) sin(Φ)]
2
2
U I
U I
= max max cos(Φ) + max max cos(2ωt + Φ)
2
2
=
P(t) is called as the instantaneous power signal. The ideal p(t) consists of the dc component and ac
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BL6503 Single Phase Energy Meter IC
component whose frequency is 2ω. The dc component is called as the average active power, that
is:
P=
U max I max
cos(ϕ )
2
The average active power is related to the cosine value of the phase difference between the voltage
signal and the current signal. This cosine value is called as Power Factor (PF) of the two channel
signals.
Figure1.
The Effect of phase
When the signal phase difference between the voltage and current channels is more than 90°, the
average active power is negative. It indicates the user is using the electrical energy reversely.
Operation Process
In BL6503, the two ADCs digitize the voltage signals from the current and voltage transducers.
These ADCs are 16-bit second order sigma-delta with an oversampling rate of 900 kHz. This
analog input structure greatly simplifies transducer interfacing by providing a wide dynamic range
for direct connection to the transducer and also simplifying the antialiasing filter design. A
programmable gain stage in the current channel further facilitates easy transducer interfacing. A
high pass filter in the current channel removes any dc component from the current signal. This
eliminates any inaccuracies in the real power calculation due to offsets in the voltage or current
signals.
The real power calculation is derived from the instantaneous power signal. The instantaneous
power signal is generated by a direct multiplication of the current and voltage signals. In order to
extract the real power component (i.e., the dc component), the instantaneous power signal is
low-pass filtered. Figure 2 illustrates the instantaneous real power signal and shows how the real
power information can be extracted by low-pass filtering the instantaneous power signal. This
scheme correctly calculates real power for nonsinusoidal current and voltage waveforms at all
power factors. All signal processing is carried out in the digital domain for superior stability over
temperature and time.
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BL6503 Single Phase Energy Meter IC
I
V
current
sampling
voltage
sampling
analog to
digital
high pass
filter
analog to
digital
digital
multiplication
high pass
filter
CF
low pass
filter
F1
F2
instantaneous real
power signal
instantaneous
power signal p(t)
V*I
digital to
frequency
integral
p(t)=i(t)*v(t)
v(t)=V*cos(wt)
i(t)=I*cos(wt)
V*I
2
p(t)=
V*I
2
V*I
2
[1+cos(2wt)]
t
t
Figure 2.
Signal Processing Block Diagram
The low frequency output of the BL6503 is generated by accumulatingm this real power
information. This low frequency inherently means a long accumulation time between output
pulses. The output frequency is therefore proportional to the average real power. This average real
power information can, in turn, be accumulated (e.g., by a counter) to generate real energy
information. Because of its high output frequency and hence shorter integration time, the CF
output is proportional to the instantaneous real power. This is useful for system calibration
purposes that would take place under steady load conditions.
VOLTAGE CHANNEL INPUT
The output of the line voltage transducer is connected to the BL6503 at this analog input. As
Figure4 shows that channel V2 is a fully differential voltage input. The maximum peak differential
signal on Channel 2 is ±660mV. Figure4 illustrates the maximum signal levels that can be
connected to the BL6503 Voltage Channel.
V1
+660mV
Maximun input differential voltage
± 660mV
V2P
+
V1
V2N
V2
-
V2
-660mV
Maximun input common-mode voltage
± 100mV
AGND
Figure 4.
Voltage Channels
Voltage Channel 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
BL6503 can be driven with common-mode voltages of up to 100 mV with respect to AGND.
However, best results are achieved using a common mode equal to AGND.
Figure5 shows two typical connections for Channel V2. The first option uses a PT (potential
transformer) to provide complete isolation from the mains voltage. In the second option, the
BL6503 is biased around the neutral wire and a resistor divider is used to provide a voltage signal
that is proportional to the line voltage. Adjusting the ratio of Ra and Rb is also a convenient way
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BL6503 Single Phase Energy Meter IC
of carrying out a gain calibration on the meter.
RF
CT
V2P
CF
± 660mV
RF
AGND
V2N
+
-
CF
AGND
Phase Neutral
AGND
CF
Ra
Rb
AGND
Rv
AGND
± 660mV
V2P
Phase Neutral
RF
AGND
V2N
Ra >> RF
Rb+Rv=RF
Figure 5.
+
-
CF
AGND
AGND
Typical Connections for Voltage Channels
CURRENT CHANNEL INPUT
The voltage outputs from the current transducers are connected to the BL6503 here. The
maximum differential voltage on Current Channel 2 is ±660mV. The maximum common-mode
voltage is ±100mV.
Power Supply Monitor
The BL6503 contains an on-chip power supply monitor. If the supply is less than 4V±5% then
the BL6503 will go in an inactive state, i.e. no energy will be accumulated when the supply
voltage is below 4V. This is useful to ensure correct device operation at power up and during
power down. The power supply monitor has built-in hysteresis and filtering. This gives a high
degree of immunity to false triggering due to noisy supplies.
The trigger level is nominally set at 4V, and the tolerance on this trigger level is about ±5%. The
power supply and decoupling for the part should be such that the ripple at VDD does not exceed
5V±5% as specified for normal operation.
SLiM technology
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BL6503 Single Phase Energy Meter IC
The BL6503 adopts the technology of SLiM (Smart Low current Management) to decrease the
static power greatly. The static power of BL6503 is about 12mW. It is half of the previous product
BL0955 (about 25mW ).This technology also decreases the request for power supply design.
BL65XX series products used 0.35um CMOS process. The reliability and consistency are
advanced.
OPERATION MODE
Transfer Function
The BL6503 calculates the product of two voltage signals (on Channel 1 and Channel 2) and then
low-pass filters this product to extract real power information. This real power information is then
converted to a frequency. The frequency information is output on F1 and F2 in the form of active
low pulses. The pulse rate at these outputs is relatively low. It means that the frequency at these
outputs is generated from real power information accumulated over a relatively long period of
time. The result is an output frequency that is proportional to the average real power. The average
of the real power signal is implicit to the digital-to-frequency conversion. The output frequency or
pulse rate is related to the input voltage signals by the following equation. (use 3.58MHz
oscillator)
Freq =
8.34 × V (v) × V (i ) × gain × FZ
2
VREF
Freq——Output frequency on F1 and F2 (Hz)
V(v)——Differential rms voltage signal on Channel 1 (volts)
V(i)——Differential rms voltage signal on Channel 2 (volts)
Gain——1, 2, 8 or 16, depending on the PGA gain selection, using logic inputs G0 and G1
Vref——The reference voltage (2.42 V±8%) (volts)
Fz——One of four possible frequencies selected by using the logic inputs S0 and S1.
S1
S0
Fz(Hz)
XTAL/CLKIN
0
0
1.7
CLKIN/2^21
0
1
3.4
CLKIN/2^20
1
0
6.8
CLKIN/2^19
1
1
13.6
CLKIN/2^18
Frequency Output CF
The pulse output CF (Calibration Frequency) is intended for use during calibration. The output
pulse rate on CF can be up to 128 times the pulse rate on F1 and F2. The following Table shows
how the two frequencies are related, depending on the states of the logic inputs S0, S1 and SCF.
Mode
SCF
S1
S0
CF/F1 (or F2)
1
1
0
0
128
2
0
0
0
64
3
1
0
1
64
4
0
0
1
32
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BL6503 Single Phase Energy Meter IC
5
1
1
0
32
6
0
1
0
16
7
1
1
1
16
8
0
1
1
2048
Because of its relatively high pulse rate, the frequency at this logic output is proportional to the
instantaneous real power. As is the case with F1 and F2, the frequency is derived from the output
of the low-pass filter after multiplication. However, because the output frequency is high, this real
power information is accumulated over a much shorter time. Hence less averaging is carried out in
the digital-to-frequency conversion. With much less averaging of the real power signal, the CF
output is much more responsive to power fluctuations.
GAIN SELECTION
By select the digital input G0 and G1 voltage (5V or 0V), we can adjust the gain of current
channel. We can see that while increasing the gain, the input dynamic range is decreasing.
G1
G0
Gain
Maximum Differential
Signal
0
0
1
±660mV
0
1
2
±330mV
1
0
8
±82mV
1
1
16
±41mV
ANALOG INPUT RANGE
The maximum peak differential signal on Voltage Channel is ± 660 mV, and the common-mode
voltage is up to 100 mV with respect to AGND.
The analog inputs V1A, V1B, and V1N have the same maximum signal level restrictions as V2P
and V2N. However, The Current Channel has a programmable gain amplifier (PGA) with
user-selectable gains of 1, 2, 8, or 16. These gains facilitate easy transducer interfacing. The
maximum differential voltage is ±660 mV and the maximum common-mode signal is ±100
mV.
The corresponding Max Frequency of CF/F1/F2 is shown in the following table.
SCF
S1
S0
Fz
Max Frequency
of F1, F2 (Hz)
DC
CF Max Frequency (Hz)
AC
DC
AC
1
0
0
1.7
0.72
0.36
128×F1,F2=92.16
128×F1,F2=46.08
0
0
0
1.7
0.72
0.36
64×F1,F2=46.08
64×F1,F2=23.04
1
0
1
3.4
1.44
0.72
64×F1,F2=92.16
64×F1,F2=46.08
0
0
1
3.4
1.44
0.72
32×F1,F2=46.08
32×F1,F2=23.04
1
1
0
6.8
2.88
1.44
32×F1,F2=92.16
32×F1,F2=46.08
0
1
0
6.8
2.88
1.44
16×F1,F2=46.08
16×F1,F2=23.04
1
1
1
13.6
5.76
2.88
16×F1,F2=92.16
16×F1,F2=46.08
0
1
1
13.6
5.76
2.88
2048×F1,F2=11.8K
2048×F1,F2=5.9K
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BL6503 Single Phase Energy Meter IC
Application
Notice:Sample tested during initial release and after any redesign or process changes
that may affect parameter. Specification subject to change without notice. Please ask
for the newest product specification at any moment.
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