IRMCS1071

Crystal

A 4 MHz crystal is used to generate the system clock. Actual system frequency is adjustable by changing

Phase Locked Loop configuration through Special Function Registers. For more information regarding the

clock, please refer to the IRMCK171/IRMCK143 Reference Manual.

Reset Circuit

IRMCK171 doesn’t require external RC circuit for reset. The reset switch can be used to initialize the JTAG

debugger. For more information regarding reset, please refer to the IRMCK171/IRMCK143 Reference

Manual.

EEPROM

The board is equipped by an EEPROM. With the provided setup the EEPROM is not used but it provides

the user with the option of storing drive parameters etc.

Digital I/O

Only some of the digital I/O’s are used in IRMCS1071. However, all general purpose I/O’s are connected to

a header (J2). In addition, a number of test points have been added for easy debug of the system.

Analog Input

Analog channels are connected to test points for ease of use.

Single Shunt Current Feedback

IRMCK171 contains an high speed Operational Amplifier for single shunt current reconstruction. Resistors

and capacitors for amplifier circuit are placed very close to the pins. Note that there is a separate trace from

shunt resistor instead of sharing a plane with negative DC bus ground to get better current feedback.

Socket

The control IC is mounted in a 48 pin socket to make replacement easy. If the user wishes to update the

IC’s software, e.g. when updating the 8051 program, replacement can be done without soldering.

IRAM

IRAM336-025SB in mounted on a heat sink. Voltage across a 500 mΩ shunt is fed to ‘Itrip’ pin of IR2136

high voltage gate driver IC through low pass filter with 400 nsec time constant to initiate the over-current

shutdown (Gatekill). For more information regarding IRAM, please refer to IRAM datasheet.

Power Supply

Switch mode power supply operates at about 80 kHz and generates 15V(VCC), 3.3V and isolated 5V. 6.5V

(VPP) is generated from 15V by a linear regulator.

EMI Filter

Passive EMI filter on the board consists of two 0.1 µF X-caps and two 2.2 nF Y-caps and a 1 mH common

mode inductor.

DC Bus Capacitor

A 100 µF, 400 V, 85

°C electrolytic capacitor is used to supply instantaneous power to the IRAM.

IRMCS1071 does not have a dynamic braking unit. In case of field weakening operation, it is recommended

to use an external regenerative unit or a braking unit for safety. GND and DCP can be used for connecting

an external unit.

This document is the property of International Rectifier and may not be copied or distributed without expressed consent.

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