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.
Once you understand unidirectional PWM of an inductive motor load, we can expand the concept to a bidirectional h-bridge PWM circuit. Read the rest of this entry »
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.
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.
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. Read the rest of this entry »