November 2012

Doc ID 023542 Rev 1

1/13

UM1559

User manual

STEVAL-IHM041V1: hardware description

Introduction

The STEVAL-IHM041V1 is a Triac based phase angle control for universal motor speed

control using an STM8S103F3, 8-bit microcontroller, to set the conduction angle of the Triac.

The board may be operated in either open loop mode or in closed loop speed control mode,

with an AC tach, hall sensor or opto sensor feedback. The open loop mode may also be

used as a lamp dimmer.

The board is designed to operate from a 120 V/60 Hz mains, but may be easily modified to

operate on other mains voltages by changing components in the power supply and motor

voltage sensing circuits. Suggested component values for other mains voltages are shown

in the alternate bill of materials.

On power-up, the firmware determines if jumper J4 is installed or not. The board operates in

open loop mode if J4 is not installed and in closed loop mode if J4 is installed. When

operating in closed loop mode, an AC tach or a hall effect device is connected to J3 to

provide speed feedback.

Figure 1.

Board image

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