AN4121 Datasheet, PDF (1/26 Pages) Fairchild Semiconductor – Design of Power Factor Correction Circuit

AN4121
Application note
Poly-phase demonstration kit with the STPMC1 and STPMS2
Introduction
This application note describes the poly-phase demonstration kit with the STPMC1 and
STPMS2.
The STPMC1 is a metering ASSP implemented in an advanced 0.35 µm BCD6 technology.
The STPMC1 device works as an energy calculator in power line systems utilizing a
Rogowski coil, current transformer, shunt or Hall current sensors. Used in combination with
one or more STPMS2 ICs, it implements all the functions needed in a 1-, 2- or 3-phase
energy meter, providing effective measurement of active and reactive energies, V_RMS, I_RMS,
instantaneous voltage and current per phase in 1-, 2- or 3-phase wye and delta services,
from 2 to 4 wires.
In a standalone configuration, the STPMC1 outputs a pulse train signal having a frequency
proportional to the cumulative active power, and it can directly drive a stepper motor,
therefore implementing a simple active energy meter.
This device can also be coupled with a microprocessor for multifunction energy meters. In
this case, measured data are read at a fixed time interval from the device internal registers
by the microcontroller through an SPI interface.
The STPMS2 is an ASSP designed to be the building block for single or multiphase energy
meters. It consists of a preamplifier and two 2^nd order Δ∑ modulators, band-gap voltage
reference, a low-drop voltage regulator and DC buffers in its analog section and clock
generator and output multiplexer in its digital section.
The demonstration kit is made up of a main board with the STPMC1 onboard (STEVAL-
IPE0010V1), and it can be coupled with up to 5 daughterboards, each having an STPMS2
onboard to sense the voltage and current of each phase (STEVAL-IPE0014V1).
Figure 1. Demonstration kit block diagram
N RST
Cur r ent
Sens or
Vol t age
Sens or
S T P MS 2
S T PMS 2
S T PMS 2
AM12798v1
VOT P MON MOP L E D
S CS
VCC
DAR
S YN- NP
DAS
DAT
S T PMC1 ^{SCL- NC}
P1
S DA- T D
DAN
DAH
CL K
XTAL 1
VDD
XTAL 2 VS S VS S A
S T PMS 2
November 2012
Doc ID 023243 Rev 1
1/26
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