1. Host PCB Description

The host PCB receives power input from a 3-phase line and control signals provided by the user. In conjuntion with

the power module the result is a flexible power conversion system, primarily designed for interface with a 3HP

Motor, however other 3-phase loads may also be applied. The host PCB supports soft-start function which reduces

inrush current by using an NTC thermistor. Surge suppression is implemented using MOV’s as a further degree of

protection. Also on-board is a regulated low voltage power supply to provide bias for the IR2233J and other low

voltage components. When connected to the power module, the unit is fully protected against overcurrent and

ground faults through DC bus voltage and current feedback. Over-temperature is guarded against through feedback

from a thermistor embedded within the power module. A 16-pin single in line header connector is provided to

interface control signals and two terminal blocks connect 3-phase AC inlet and output to the load. The user

provides 5V CMOS / TTL level signals which are then processed by the IR2233J Control IC and delivered to the

power module.

Signals Available to User

In addition to availability of bias supplies derived for the host PCB, signals from the power module circuits and those

derived and processed on the host PCB such as fault status are available to the user. Current feedback signal from

the low side shunt is available on the IFB pin at 0.025V/A. If filtering of this signal is required to remove noise, a high

impedance buffer stage should be inserted between signal and filter. DC bus voltage feedback is provided on the

VFB pin. This reference is been scaled down by a factor of 100 and should be protected with a high impedance

buffer stage.

Fault Behavior.

The system is designed to tolerate overload conditions for one minute. The user should prevent such conditions

persisting beyond this period. In the event of shutdown initiated by ground-fault, overcurrent or over-temperature, the

inverter outputs are terminated and an LED will light to signal this condition. For more information on fault response

for IR2233J, please consult the data sheet.

IRMDAC3 Kit Overview and System Benefits

·

When furnished with user-provided logic level control signals, the IRMDAC3 forms a complete reference design

for a 3HP AC motor. Unlike outdated circuits based upon transformer drive or opto-couplers, the system uses

International Rectifier proprietary level-shifting gate drive circuits integrated within the IR2233J Control IC.

Separation of gate drive / control and low-voltage circuits from the power module included in the kit results in a

compact, effecient system. The user benfits from immediate hands-on experience and may customize at will

using shematics and circuit ideas as the basis for production designs.

·

Gate drive, control and protection circuits are designed to closely match the operating characteristics of the

power semiconductors. This allows power losses to be minimized and power rating to be enhanced to a greater

extent than is possible by designing with individual components.

IRMDAC3

Reference Design Data Sheet (October 1998)