Require help with building H-bridge

Hi guys

I recently purchased a Kysan NEMA 17 stepper motor (4 wire - Bipolar) - I'm currently waiting on the driver module but thought it would be beneficial for me to learn how to control one without using the driver.

This means the first step is to make an H-bridge - I'm aware I need to make it using transistors but I don't really know how. I have googled some things but I would like a different take on it and get some extra info. A lot of circuit I'm finding is just using a chip for an H bridge.

Could someone perhaps indicate to me a circuit with transistors, resistors, and connections with the 4 wires from the motor to the arduino. I don't really need push buttons - I just want to see the motor spin :D

Thanks in advance

It helps here are some specifications of my motor

Nema Motor Specifications

Nema Motor Specifications

  • Model number: 1124090
  • Holding Torque:
  • Rated Voltage: 4.2V
  • NO.of Phase: 2
  • Step Angle: 1.8° ± 5%
  • Resistance Per Phase: 2.8Ω± 10%
  • Inductance Per Phase: 4.8mH± 20%
  • Current Per Phase: 1.5A
  • Shaft: 5mm diameter w/ one flat
  • Insulation Class: Class B
  • Dielectric Strength: 100MOhm
  • Operation Temp Range: -20 ~ +40° C
  • Lead Wire: 22AWG / 750mm
  • 4 pin 2.54mm connector

Well that sort of bipolar motor really wants a chopper drive, not H-bridge (it would be dual-H-bridges BTW, one for each winding).

If you have a 4.2V power supply you could use H-bridges, but you'd not get the motor to turn very fast at all.

Bipolars with low resistance windings like this are meant for constant-current chopper drivers.

An H-bridge for low voltage high current can be done two ways - either a proper MOSFET H-bridge setup with all n-channel devices and some driver such as HIP4081 to drive them and generate bootstrapped gate drive. Or you can use complementary darlingtons, and 6V supply (the darlingtons will waste 2V at least, so still nominally 4V to the windings).

Thanks Mark, im waiting on a Pololu A4988 driver

I was not aware that i needed a constant - current chopper driver - i would to look into what that actually is and how to do one.

If you have some time, could you perhaps provide some guidance for a circuit I could do,

Thanks in advance, ill be sure to do some extra research.

The Pololu A4988 -is- a chopper driver, so you are set.

Basically, it is a dual H-bridge that is connected as a constant current switch mode regulator, and the stepper windings are the inductor in the circuit -and- the load.


Can you perhaps provide a circuit i could build for learning purposes just to get the motor working without using the driver - id like to actually learn whats going on

It is not a trivial circuit. That's why there are a bunch of chips designed just to accomplish this.

The page on the A4988 chip on the Pololu A4988 driver board, from Allegro Micro: