When it comes to MOSFET datasheets, you have to know what you’re looking for. While certain parameters are obvious and explicit (BVDSS, RDS(ON), gate charge), others can be ambiguous at best (ID, SOA curves), while others can be downright useless at times (see: switching times).
In complicated power designs, metal-oxide semiconductor field-effect transistor (MOSFET) selection has a tendency to be somewhat of an afterthought. While it’s just a three-pin device, appearances can be deceiving and trying to select the correct MOSFET or “FET” can be a task more complicated than you might think. In this 7-part blog series, we analyze a variety of typical FET applications, from power supply to motor control, and address the various concerns and trade-offs that dictate the FET selection process.
For anti-tampering, it is common to try to detect the presence of a strong magnet. In this section, we will cover the use of hall sensors for low-power detection of strong magnetic fields in three dimensions. Details on our magnetic tamper detection reference design, TIDA-00839, will be provided as well as some of the design considerations that were kept in mind when creating this reference design.
In this section, we will cover how to harden a meter against these magnetic tamper attacks by using shunts for current sensors. For poly-phase implementations, I will go over how to use isolated delta sigma modulators to add the necessary isolation to use shunt current sensors and create magnetically immune poly-phase energy measurement systems. The TIDA-00601 and TIDA-01094 reference designs, which show how to implement a poly-phase isolated shunt measurement system, will be discussed as well as the associated AMC1304 high-side power supplies used in these designs.
The below introductory section features a video briefly discussing what exactly multi-phase buck regulators are, what applications they're suited for, and some of the challenges associated with implementing them. Additionally, the listed resources dive a little deeper into the topics covered in the video, providing further instruction in the beginning of your multiphase journey.
In designing with multiphase, Carmen works through a six-phase design for powering the core voltage of a networking ASIC, Marketing Manager George Lakkas explains why multiphase converters are ideal for high currents, and TI engineers blog about common concerns and use contexts.
In testing in the lab, Carmen takes a six phase buck regulator through basic validation testing in the lab with plenty of tips and waveforms shared. Let Carmen show you how to test transient response, input and output ripple, phase stability, and thermal performance. Additionally, TI engineers blog about various lab tricks related to multiphase devices.
PCB layout tips to manage heat dissipation with your switching regulator
Another way to manage thermals is through IC packaging. Smaller and smaller packages continue to be introduced as output currents trend upward. Learn more about the packaging technologies that aid heat dissipation under these challenging conditions and enable high power density.