Stepper motors can be configured for unipolar or bipolar drive; each approach has different performance attributes and tradeoffs. Despite their usefulness and suitability of stepper motors for precision positioning, especially in back-and-forth motion applications, one of the factors which delayed their widespread adoption was the challenge of providing the needed driver management. However, the introduction […]
FAQ
Unipolar vs. Bipolar drive for stepper motors, Part 2: Tradeoffs
Stepper motors can be configured for unipolar or bipolar drive; each approach has different performance attributes and tradeoffs. The previous part of this article presented the basics of different coil windings and connections for unipolar and bipolar stepper-motor configurations. As in most engineering situations, the next questions are: what is the impact of these differences? […]
Unipolar vs. Bipolar drive for stepper motors, Part 1: principles
Stepper motors can be configured for unipolar or bipolar drive; each approach has different performance attributes and tradeoffs. Stepper motors are widely used, and, as with so many basic components, they are simple in some ways but also have multiple configurations and operating subtleties. For steppers (the “motor” part of the two-word term is often […]
Voltage rail splitters and virtual grounds for batteries and PFCs
Rail splitters are usually associated with battery-powered devices, but that’s not always the case. There are several definitions of a “rail splitter,” sometimes referred to as a “virtual ground” or “pseudo ground.” The most common meaning is creating a new “0V” reference point, usually the mid-point Vin/2 of a single supply voltage such as a […]
Power supply regulations, requirements, and standards
Regulatory standards cover safety and electromagnetic compatibility (EMC) and efficiency. Safety and EMC standards are relatively straightforward, and their numbers are limited. Efficiency is a different matter: Society’s drive to reduce greenhouse gas emissions results in increasingly sophisticated energy efficiency standards for all types of power converters. It started with relatively simple ENERGY STAR standards […]
Power supply control techniques
Power supply control has evolved from primitive ferroresonant regulation and linear power supplies to simple hysteretic control, analog voltage-mode control, analog current-mode control, and now various approaches to digital control. Compared with switched-mode power supplies, the output of ferroresonant designs is not as precisely regulated, while linear regulation can produce very tightly regulated and very […]
Two- and four-switch power conversion topologies
Compared with one-switch topologies, two- and four-switch power conversion topologies have several benefits in addition to the ability to process higher power levels. This FAQ will review some of the basic two-, and four-switch topologies. It will look at where they are used and their performance tradeoffs. This article does not consider various switched capacitor […]
What is one-switch power conversion?
DC/DC conversion is the basic building block for many power converter designs including AC/DC power supplies, battery chargers, and uninterruptible power systems. This FAQ reviews some of the most common one-switch topologies. Specialty topologies such as the Joule Thief are not included. This article also does not consider various switched capacitor topologies, a review of […]
Don’t rush to choose rechargeable batteries…at least, not yet
Using energy harvesting and a rechargeable battery to power a remote wireless IoT node seems like an obvious and straightforward solution, but there are some unique aspects to consider. Don’t get me wrong: I really like rechargeable batteries; in fact, I like them a lot. Whether based on lead-acid, nickel-cadmium, lithium-ion, or other chemistry, our […]
Power factor correction topologies
With the rise of green energy and transportation technologies, power factor correction (PFC) is growing in importance. PFC is an integral aspect of green energy designs since it can improve energy efficiency. PFC topologies can be passive, partial switching, or active, depending on system requirements. The appearance of wide bandgap power semiconductors combined with advanced […]
