71M6511 Datasheet, PDF (76/95 Pages) Teridian Semiconductor Corporation – Single-Phase Energy Meter IC

71M6511/71M6511H
Single-Phase Energy Meter IC
DATA SHEET
AUGUST 2007
APPLICATION INFORMATION
Connection of Sensors (CT, Resistive Shunt, Rogowski Coil)
Figure 29 and Figure 30 show how resistive dividers, current transformers, restive shunts, and Rogowski coils are connected
to the voltage and current inputs of the 71M6511.
VA = Vin * R_out/(R_out + R_in)
core
Vout = R * I_out = R * I_in/N
VA
I_in
I_out
I_in
IA
V_in
R_in
R_out
R
V_out
V3P3
1/N
Filter
I_out
Figure 29: Resistive Voltage Divider (left), Current Transformer (right)
Vout = R * I_in
I_in
IA
R
V_out
V3P3
I_{in 1/N} ^{Vout = dI}in ^/dt
R
V_out
IA
V_C
V3P3
I_in
Figure 30: Resistive Shunt (left), Rogowski Coil (right)
Distinction between 71M6511 and 71M6511H Parts
71M6511H parts go through a process of trimming and characterization during production that make them suitable to high-
accuracy applications.
The first process applied to the 71M6511H is the trimming of the reference voltage, which is guaranteed to have accuracy over
temperature of better that ±10PPM/°C.
The second process applied to the 71M6511H is the characterization of the reference voltage over temperature. The
coefficients for the reference voltage are stored in so-called trim fuses (I/O RAM registers TRIMBGA, TRIMBGB, TRIMM[2:0].
The MPU program can read these trim fuses and calculate the correction coefficients PPM1 and PPM2 per the formulae given
in the Performance Specifications section (VREF, VBIAS). See the Temperature Compensation section for details.
The fuse TRIMBGB is non-zero for the 71M6511H part and zero for the 71M6511 part.
Trim fuse information is not available for non-H parts. Thus, the standard are to be applied. These settings are:
• PPMC = TC1 * 22.46 = –149
• PPMC2 = TC2 * 1150.1 = –392
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© 2005-2007 TERIDIAN Semiconductor Corporation
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