Li-ion battery charger ICs are devices that regulate battery charging current and voltage, and are commonly used for portable devices, such as cellphones, laptops, and tablets. Compared to other battery chemistries, Li-ion batteries have one of the highest energy densities, provide a higher voltage per cell, can tolerate higher currents, and do not have to be trickle charged when the battery is fu...

Electrical equipment such as industrial medical equipment, robot vacuums, drones, and high-power speakers need multi-cell battery chargers for power. The traditional solution for multi-cell battery chargers is composed of several discrete power MOSFETs and multiple auxiliary components. Figure 1 shows that in a traditional solution, designers need at least two power MOSFETs for a power converter,...

The MP2639A is a fully integrated and flexible battery charge management IC that can charge two cells in series from a 5V power supply. USB ports are widely used by portable devices due to their universal compatibility and reduced e-waste of in-box power supplies. Furthermore, with the increased proliferation of USB Type-C, it is now possible to draw up to 15W of power from a standard USB power su...

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...

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...

When starting a DC motor, large currents can be required that place a burden on the motor driver and power supply. This article will discuss using the current regulation function integrated into many motor driver ICs, while using examples from Monolithic Power Systems (MPS) to address high-current conditions. In many cases, using current regulation can allow designers to use a smaller motor drive...