Article

Flexible Stepper Motor Driver

With electrically isolated interface

To enable the control of a stepper motor from, say, a parallel port of a PC, Elektor Labs has designed a compact driver PCB using the A3979 chip made by Allegro Microsystems. This chip has been specifically designed to control bipolar stepper motors in full-, half-, quarter- and sixteenth-step modes at currents of up to 2.5 A. The circuit is provided with optocouplers for electrical separation between the control inputs and the driver module.

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Materials

110018-PCB.pdf

Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits or AISLER as the best services for its own prototypes and volume production.

The use of our Gerber files is provided under a modified Creative Commons license. Creative Commons offers authors, scientists, educators and other creatives the freedom to handle their copyright in a more free way without losing their ownership.

PCB

Download Gerber file: 110018-1.zip

Extra info / Update

* Suitable for most small bipolar stepper motors
* Integrated DMOS-bridges, maximum voltage/current: 30 V / 2.5 A
* default current limit: 1.5 A
* Electrically isolated control lines using optocouplers
* Full-, half-, quarter- and sixteenth-step mode settable using solder bridges
* PWM control for minimal dissipation
* Built-in translator for controlling the motor
* Built-in blanking function for the DMOS bridges
* Various protection features built in (current and temperature, among others)

Components

The BOM (Bill of Materials) is the technically exhaustive listing of parts and other hardware items used to produce the working and tested prototype of any Elektor Labs project. The BOM file contains deeper information than the Component List published for the same project in Elektor Magazine. If required the BOM gets updated directly by our lab engineers. As a reader, you can download the list here.
Want to learn more about our BOM list? Read the BOM list article for extra information.

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Component list

Resistors (SMD 0603)
R1,R12 = 12kOhm
R2,R3,R4,R6,R7,R8,R14 = 1kOhm
R5 = 3.3kOhm
R9 = 22kOhm
R10,R11 = 0.100Ohm (SMD2512, e.g. Bourns CRA2512-FZ-R100ELF; Farnell # 1435952)
R13 = 2.2kOhm
P1 = 10kOhm trimpot (e.g. Vishay TS53YJ103MR10; Farnell # 1141485)
Capacitors
C1,C13 = 220nF (SMD0603)
C3 = 220nF (SMD0805)
C4 = 100µF (case F, e.g. Panasonic EEEFK1H101P; Farnell # 9695958)
C5,C6,C7 = 100nF (SMD0805)
C8,C9 = 470pF (SMD0603)
C10,C14 = 100nF (SMD0603)
C12 = 47µF (SMD 6032, e.g. Vishay 593D476X9010C2TE3; Farnell # 6844626)
Inductor
L1 = 100µH (SMD5750, e.g. Epcos B82442H1104K, Farnell # 158896)
Semiconductors
D1,D2,D3 = LL4148 (SOD80; Farnell #9843710)
D4 = LED, green, 20 mA (SMD 0603)
D5,D6 = PMEG6030EP Schottky diode (SOD128; Farnell #1829207)
IC1 = ACPL-847-30GE (SOP16; Farnell #1339045)
IC2 = A3979SLP-T (Farnell #1521716)
IC3 = LM2594M-5.0 (SO8, Farnell #9779841)
Miscellaneous
K1,K2 = solder jumper on board
K3 = 4-pin plug, right angled, 8A, 3.5mm pitch (e.g. Phoenix Contact 1844236 MC1.5/4-G-3.5; Farnell #1843622)
Mating 4-way socket with screw terminals
K4 = 6-pin plug, right angled, 8A, 3.5mm pitch (e.g. Phoenix Contact 1844252 MC1.5/6-G-3.5, Farnell #1843648)
Mating 6-way socket with screw terminals
Heatsink for IC2 (Fischer ICK SMD A 13 SA; Farnell #4302199)
Matching double-side adhesive tape 6x10 mm
PCB # 110018-1