DG-IRMCK203 Datasheet, PDF (5/67 Pages) International Rectifier – Application Developer’s Guide

IRMCK203 Application Developer’s Guide
1 Introduction
This document is provided as a supplement to the datasheet for the IRMCK203. It provides detailed information
about the internal design and external interfaces of the product and describes how to configure the operation to
conform to the requirements of a custom application. This document is intended for engineers who are developing
an application using the IRMCK203 digital control IC.
The document is divided into three main sections. In the Concepts section, system design concepts are presented and
theory of operation is described in detail. This section provides the background needed to begin IRMCK203
application development. The Techniques section provides practical “how-to” information, tips and examples to
assist with the development process. The Reference section provides a complete definition of the host register map
with a short description of each register and field. The registers are listed in sequential order for easy reference.
1.1 Constraints
The following are constraints for use of the IRMCK203 with a custom hardware system.
Analog Interface
The IRMCK203 has a built-in interface to the ADS7818 (BurrBrown) serial A/D converter (12 bit). Dc bus
voltage feedback, external speed reference and Leg Shunt current can be obtained via ADS7818 in conjunction
with MUX circuitry. An analog feedback application example is given in Section 2.4.2.
Current Feedback Interface
The IRMCK203 has a built-in interface circuit for two IR2175 motor current sensing high voltage ICs. With two
IR2175 and two shunt resistors, the motor phase currents can be obtained for motor control purposes. A 10-bit
resolution of current feedback data can be obtained. The practical power level limit for using shunt resistors is
up to 3.7 kW. For a higher horsepower application, a resistor shunt becomes impractical due to power dissipation
of shunt resistors (insert in series between motor and drive).
The IRMCK203 provides other means of current feedback through the use of an ADS7818 (BurrBrown) serial
A/D converter and Inverter Leg Shunt resistor. Inverter Leg Shunt currents can be used (reconstruction of phase
current inside IRMCK203) instead of IR2175 current feedback. However, the Leg Shunt option is recommended
only for an Inverter switching frequency less than 10KHz.
1.2 Application Connections
Figure 1 shows a typical application connection block diagram. In order to complete a Sensorless drive control, all
necessary components are shown in connection to IRMCK203. A fully self-contained drive evaluation board
(IRMCS2031) based on the IRMCK203 Digital Control IC is available for drive performance evaluation.
The figure shows a typical hardware configuration. Users can customize the design without the effort of modifying
code.
This document is the property of International Rectifier and may not be copied or distributed without expressed consent.
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