November 2012

Doc ID 023243 Rev 1

1/26

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

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

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

AM12798v1

Current

Sens or

Vol t age

Sens or

STPMS2

STPMS2

STPMS2

STPMS2

STPMC1

DAR

DAS

DAH

CL K

XTAL 1

XTAL 2

VSS VSS A

MOP

MON

VOT P

VCC

DAN

DAT

VDD

SDA- TD

SCL - NC

SYN- NP

SCS

LED

STPMS

M

M 2

STPMS

M

M 2

STPMS

M

M 2

P1

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