At the 2007 Minos micromouse conference, Martin Barratt gave a talk about his stepper motor driving scheme. For best performance, steppers really need to be driven by a high voltage. However, the current will need to be limited to prevent the motor overheating. Normally this is done with dropper resistors which waste all the energy or with chopper drives that can be relatively complex. Martin has an alternative approach that provides the high voltage needed to produce fast step rates and the low current needed to reduce dissipation and keep the battery size under control.