BL0921
FEATURES
High accuracy, less than 0.1% error over a
dynamic range of 500: 1
On-chip oscillator as clock source
Exactly measure the real power in the positive
orientation and negative orientation, calculate the
energy in the same orientation
Two current monitors continuously monitor the
phase and neutral currents in two-wire distribution
systems. Uses the larger of two currents to bill, even
during a Fault condition
A PGA in the current channel allows using small
value shunt and burden resistance
The low frequency outputs F1 and F2 can
directly drive electromechanical counters and two
phase stepper motors and the high frequency output
CF, supplies instantaneous real power, is intended for
calibration and communications
Two logic outputs REVP and FAULT can be used
to indicate a potential orientation or Fault condition
On-Chip power supply detector
On-Chip anti-creep protection
On-Chip voltage reference of 2.5V±8%
Single 5V supply
Low static power (typical value of 25mW).
The technology of SLiM (Smart–Low–current–
Management) is used.
Credible work, working time is more than twenty
years
Single Phase Energy Meter IC
with Integrated Oscillator
DESCRIPTION
The BL0921 is a low cost, high accuracy, high
stability, simple peripheral circuit electrical energy
meter IC. The meter based on the BL0921 is intended
for using in single-phase, two-wire distribution
systems. It can exactly measure the real power in the
positive orientation and negative orientation and
calculate the energy in the same orientation.
The BL0921 incorporates a novel fault detection
scheme that both warns of fault conditions and allows
the BL0921 to continue accurate billing during a fault
event. The BL0921 does this by continuously
monitoring both the phase and neutral (return)
currents. PIN12 (FAULT) indicates Fault condition,
when these currents differ by more than 12.5%.
Billing is continued using the larger of the two
currents when the difference is greater than 14%.
The BL0921 supplies average real power
information on the low frequency outputs F1 (Pin16)
and F2 (Pin15). These logic outputs may be used to
directly drive an electromechanical counter and
two-phase stepper motors. The CF (Pin14) logic
output gives instantaneous real power information.
This output is intended to be used for calibration
purposes or interface to an MCU.
BL0921 thinks over the stability of reading
error in the process of calibration. Bulk test data
indicate that in the condition of small signal 5%Ib
(Ib=5A), the error of CF is less than 0.1%. An internal
no-load threshold ensures that the BL0921 does not
Interrelated patents are pending
exhibit any creep when there is no load.
BLOCK DIAGRAM
VREF
VDD
V1A
V1B
V1N
V2N
V2P
VREF
GND
1
16
VDD
input contron
internal
oscillator
power
detector
F1
F2
CF
REVP
voltage
reference
2
15
3
14
4
BL0921
13
V1A
V1B
V1N
V2P
V2N
BL0921
high
pass
filter
high
pass
filter
digital
multiplic
ation
low
pass
filter
digital
to
frequency
and
output
current
sampling
analog
to
digital
analog
to
digital
5
12
FAULT
6
11
G
S0
S1
voltage
sampling
FAULT
REVP
CF
F1
F2
7
10
logic contron
8
9
G
S0
S1
SOP 16
http://www.belling.com.cn
-1-
Total
13 Pages
3/15/2007
BELLING [ SHANGHAI BELLING CO., LTD. ]
