Unlike components that strive to solve a wide range of problems, or parts that have achieved astonishingly widespread use and lifespan (think of the basic LDO or the ubiquitous 2N2222 transistor), most power-related ICs I see are meticulously targeted at well-defined application domains. They typically add a few small but important features and functions that make them ideal for solving tricky problems for circuit/system designers. (Marketers often call these parts "ideal," but none of them are ideal; I prefer to think of them as "perfectly suited.")
Therefore, we actually have thousands of power control ICs to choose from—sometimes, having so many to look at can be overwhelming. However, if you carefully read through the various selection guides and parameter/specification tables, you'll find that almost every one has a valid reason. Some recent introductions prove this point.
For example, consider Linear Technology's LT3795 110V LED DC/DC converter and dimming controller. It's certainly efficient, but that's not exactly newsworthy on its own right now. What makes this IC particularly suitable for the application is that it adds features you need in this situation, such as robust short-circuit protection and user-selectable spread-spectrum modulation to propagate radiated energy and reduce EMI compliance issues and complaints (I have some household LED and CFL lights that are high-performance broadband EMI sources).
The LT®3795 is a DC/DC controller for regulating constant current or constant voltage, ideal for driving LEDs. It drives a low-side external N-channel power MOSFET from an internally regulated 7.7V supply. Its fixed-frequency and current-mode architecture ensures stable operation over a wide range of supply and output voltages. Spread-spectrum frequency modulation (SSFM) can be activated to improve electromagnetic compatibility (EMC) performance. The ground reference voltage FB pin serves as an input for several LED protection functions and also allows the converter to operate as a constant voltage source. The maximum output current is set by an external resistor, and the output current amplifier has rail-to-rail common-mode range. The LT3795 also includes a separate input current sensing amplifier for limiting input current. The TG pin inverts and level-shifts the PWM signal to drive the gate of an external PMO. The PWM input provides LED dimming rates up to 3000:1, and the CTRL input provides additional analog dimming capability.
Another IC from Texas Instruments, which at first glance appears similar to the LTC section but is actually quite different, is the TPS92690. This DC/DC LED driver also features an adjustable switching frequency to minimize EMI, but it is designed for automotive headlights and lighting, so it is AC line independent and operates over an input range of 4.5 to 75.0 Vdc. Furthermore, it incorporates low-side current sensing, making it more compatible with some of the dedicated LED power driver topologies used in this application.
For a very different situation, Microchip Technologies has added a new member to its UCS100X series of programmable USB port power controllers. In addition to 12W charging (2.5A), the UCS100X also supports active cables, such as the Apple Lightning connector. The UCS1002 device will automatically charge a wide variety of portable devices, including USB-IF BC1.2, YD/T-1591 (2009), most Apple and RIM devices, and many others. It comes with nine pre-loaded charger emulation profiles to maximize compatibility with these peripherals—a very thoughtful touch.
These are just a few recent examples; there are many more you can find and highlight. In each case, they are all associated with a "power control" function, but their roles are quite different. This diversity presents engineering and selection challenges, but they are worth the effort to address. Ironically, this also makes the work of various research institutions estimating the market size and changes of these types of ICs very vague and ambiguous.
Have you recently seen any power control and management ICs that appear to have truly innovative features and functionalities, and not just better specifications or improved efficiency?
