Archive for the ‘Motor Control’ Category

Understanding Mixed Decay and the Allegro A3977 PFD Percent Fast Decay Feature

Thursday, April 16th, 2009 by Tom Scarince

This article explains why you might want to use mixed decay and how it is implemented in the A3977’s current chopper PWM scheme with the percent fast decay (PFD) pin. 

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Bidirectional PWM Motor Control

Tuesday, April 7th, 2009 by Tom Scarince

Once you understand unidirectional PWM of an inductive motor load, we can expand the concept to a bidirectional h-bridge PWM circuit.  (more…)

Unidirectional PWM Motor Control

Thursday, April 2nd, 2009 by Tom Scarince

This article covers unidirectional Pulse Width Modulation (PWM) and how it can be used to control the power applied to a DC motor or the current in a stepper motor winding, for instance. While we eventually want to talk about doing bidirectional PWM with an h-bridge, we’ll start with a simple, one-direction control circuit.

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Intro to H-Bridge Motor Control Circuits

Thursday, March 26th, 2009 by Tom Scarince

Simplified H-Bridge

An h-bridge is a bipolar driver circuit that is often used to control a load such as a brush type DC motor.  This article covers the most basic concepts of a simplified h-bridge circuit. Later articles dig deeper into the details of practical h-bridge operation and design.

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Stepper Motor Wiring Options

Thursday, March 19th, 2009 by Tom Scarince

Stepper motors may come with four, five, six or eight wires. This article will help you identify the correct way to wire an unknown stepper motor. (more…)