1.7 System components

System components

The term “system components” covers a broad universe of semiconductor devices, ranging from the simply functional to the extremely complex. Given the variety in this class of components, there is one common denominator in that all of them provide solutions to specific problems. In this chapter, we will provide examples of three categories of components: integrated solutions, line drivers and basic functions.

In previous chapters, you learned how to use the device data sheet to evaluate performance and use conditions, so we will not provide a detailed technical discussion here.

Integrated solutions

Figure 1's depiction of a general system block diagram could probably represent your senior project as well. Previous chapters have described how to evaluate devices that make up such a general system: op amps for the creation of filters, control systems or input and output signal-conditioning systems, microcontrollers or DSPs that process data captured by the system, power-management solutions, wireless solutions, and interface options.

By necessity, most of the information in this book is based on basic circuit elements – an op amp, a low-dropout (LDO) regulator or a specific microcontroller – that represent the system building block under discussion. But what about real-world applications, which hopefully your senior projects are tackling? Since the invention of the integrated circuit by Jack Kilby in 1958, the semiconductor industry has continually integrated more and more into its products. From Bell Lab’s single transistor to Kilby’s integrated circuit, from Texas Instruments' single-chip DSP to today’s embedded system engines (powering smartphones, automobiles, washing machines and practically everything else), the inexorable technological march to more complex integrated solutions continues.

You might be asking yourself, “Why shouldn’t my senior project benefit from more complex solutions?” The question can also be reworded as, “What if I took advantage of application-specific solutions used by industry design teams?” The answer to both questions is that it depends. It depends on the application you are addressing and the maturity of the solution you are looking for. If a device you are interested in provides available samples on its www.ti.com page, the technology is mature enough for your senior project.

It also depends on your team’s ability to understand and manage the functionality so that it can be used properly in your system. You should also consider the trade-offs in time and effort to use an integrated solution. A simple example would be in power management. The "Power" chapter in this book introduces the various components for power management separately, yet the application of these elements to a real-world application can be complex.

Consider the challenge of creating a lithium-ion battery charger for your project. The physics of the Li-ion battery charging under load are complex and require a detailed solution. While the creation of such a charger would have once been a suitable senior project, the bq24040 is a single-input, single-cell Li-ion battery charger that provides the solution in a single device. The bq24040 charges the battery while it is powering a system load. The battery is charged in three phases: conditioning, constant current and constant voltage. Clearly, this is a sophisticated solution, which when used in your project frees team resources to address other basic elements.