Posted: October 1st, 2010 | Author: Tom Scarince | Filed under: Motor Control, Stepper Motors | Tags: A3977, Neat Components, Stepper Motor | No Comments »
Configuration: Dual H-Bridge w/ microstepping translator
Applications: Stepper Motor
Current (peak): 2.5 amps
Voltage (max): 35V
Short circuit protection: No
Built-in chopper current limitation: Yes, Full and half stepping, 4 and 8 microsteps
Interface: Step and Direction
A3977 PCB
With dual h-bridges and a built-in translator, DAC and chopper circuits, the A3977 is a nearly complete microstepping stepper motor controller on a single chip. With the addition of a handful of external passive components, this IC is ready to accept step & direction signals from a pulse generator, microcontroller, indexer or CNC controller. Each pulse applied to the Step input rotates the motor one microstep forward or reverse, depending on the state of the Direction input.
Posted: September 17th, 2010 | Author: Tom Scarince | Filed under: Motor Control, Stepper Motors | Tags: Neat Components, Servo Motor, Stepper Motor | No Comments »
Configuration: Single H-Bridge
Applications: PM DC, Servo, Stepper
Current (continuous): 3 amps
Current (peak): 6 amps
Voltage (max): 60V
Short circuit protection: Yes
Built-in chopper current limitation: Yes, 4-bit linear DAC
Interface: Parallel
Datasheet: LMD18245
Thanks to its voltage and current capability, the LMD18245 is suitable for driving small PMDC servo motors or a medium size stepper motor winding. It incorporates a unique lossless current sense output. This chip also includes a 4-bit linear DAC to generate a reference voltage for the internal chopper circuit. When used in pairs, these chips can run a stepper motor at up to 8 microsteps per full step with reasonable accuracy. The LMD18200 is a similar IC that lacks the DAC and chopper circuit.
Posted: April 16th, 2009 | Author: Tom Scarince | Filed under: Stepper Motors | Tags: A3977 | No Comments »
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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Posted: March 19th, 2009 | Author: Tom Scarince | Filed under: Stepper Motors | No Comments »
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 »