This article is the second part of a two-part series exploring how to design a secondary-side synchronous rectifier for ultra-small, fast charge adapters. Part I discussed the topology designs and power supplies for synchronous rectifiers. Part II will review how a synchronous rectifier opens and shuts down, and how new devices utilize quick shutdown technology. A self-powered circuit provides ...

Mobile devices — such as mobile phones and laptops — are integral to the modern world. The development of mobile devices has accompanied a demand for small, lightweight, and fast-to-charge adapters. Major manufacturers are rushing to introduce ultra-small, fast charge adapters (see Figure 1). This article is the first part of a two-part series exploring how to design a secondary-side synchr...

Due to the rapid development of mobile devices in the last decade, cell phone applications have expanded into every aspect of society. In day-to-day life, few people leave their cell phone, even for a few minutes. As a result, high battery capacity and fast charging speed has become one of the most critical features for cell phones, and the demand for adapters with higher power ratings and higher ...

Because optical encoders are functionally similar, “resolution” is often used as a main characteristic for magnetic encoders (a device providing the angle of a magnet attached to a mechanical shaft, under a digital form). Resolution is a key parameter since it indicates the smallest angle that the sensor is capable of resolving. Unfortunately, when comparing products, users may often be misled, as...

Modern life has become more convenient due to battery-powered applications for electric tools, vacuum cleaners, electric bikes, and outdoor power supplies for camping. As wireless charging continues to be more widely used in applications, lithium battery safety is a growing concern, so designers are looking to develop battery monitoring and protection solutions. A battery pack is made up of multi...

In Part I of this series, we covered the bipolar stepper motor’s three control modes as well as its mechanical structure, including dual full-bridge drive. In Part II, we will discuss microstepping and how it controls the dual full-bridge drive. Previously, half-step stepping mode was introduced as a combination of single-phase stepping and full-step stepping to obtain more electrical angle pos...

When designing a motor control circuit, it is vital to determine how to deliver the high current required to drive the motor. Designers must choose whether to use monolithic integrated circuits that have internal power devices, or gate driver ICs and discrete external power MOSFETs. This article discusses the advantages and disadvantages of each approach and provides guidance on when to choose eit...

In the intelligent era, stepper motors are widely used due to their unique open-loop position control performance. Each device has specific requirements that ensure there is a smooth output torque while the stepper motor rotates. Rotation stability is closely related to the motor’s physical construction as well as its control mode. This article introduces the bipolar stepper motor and discusses i...

This article is the second part of a two-part series covering power supply design for car infotainment systems. Part I discussed the performance requirements for primary and secondary power supplies in car infotainment systems. Part II addresses challenges regarding camera power supplies and USB charging in car infotainment systems. Figure 1 shows the car machine’s power architecture, including t...

A car’s infotainment system is an on-board, integrated information processing system based on the car’s bus body and internet. Vehicles have become more integrated and modular as consumers continue to raise expectations for driving, car information resources, entertainment, and safety. This trend has introduced new challenges to the research and development of car infotainment systems, particularl...

MPS recently released an integrated, compact gate driver circuit with six power MOSFETs. This article discusses the MP6540 series, including the MP6540A, MP6540H, and the MP6540HA. The MP6540 is a 3-phase, brushless DC (BLDC) motor driver that integrates three half-bridges consisting of six N-channel power MOSFETs. Conventional motor driver architecture combines a motor driver chip and the power ...