The trend toward miniaturizing medical electronics devices also brings with it a number of challenges. In this month's edition of Brainstorm, we ask industry experts in the medical electronics market what they believe to be the most critical of these challenges and what current and developing technology is available to help the designer meet those challenges.
What do you consider to be the most important factors that will further the development of power management in portable systems? What do you think are some of the customer misconceptions about power management that must overcome to move the industry forward?
As I kid, I sometimes got frustrated with what I saw as my Dad not giving me a straight answer. For instance, I would say, “Dad, I need a hammer”. “What are you using it for?” he would say. “There’s a finishing nail sticking out the wooden floor in my room and I need to pound it back in.” (I grew up in an very old farm house.) “Then you need a rubber mallet, not a hammer.
Designers are always on the lookout for semiconductors and algorithms that help to boost the efficiency of appliances with a minimum addition to the overall system cost. Motor-control systems need to compensate for system input changes and can use control algorithms to ensure the efficient operation of the motor. Using advanced algorithms, such as a field oriented control (FOC), motor torque can be controlled dynamically, keeping it constant within the rated speed range (see Figure 1). Toward this, the most commonly used motor-control loop is the Proportional Integral Derivative (PID) controller, which comprises error calculation (reference minus measured variable), compensator (controller), and output generation to the system.
Consumer electronics manufacturers must develop completely different television receiver product designs for different countries or regions. The standards and technologies for television reception vary considerably so it has been impractical to consider a single flexible design covering multiple standards or regions. However, new technologies are emerging which will make it possible to have a single product design address multiple countries or regions.
Years ago I ditched my 9600 bps modem, but I still rely on dial-up modems. Those modems exist in automated teller machines, gasoline pumps, traffic controllers, medical instruments, security systems, point-of-sale (POS) equipment, and other devices. According to several sources, dial-up modems still provide the largest number of access points to the Internet. Fortunately, several OEM vendors supply dial-up modem modules that offer drop-in communications in small packages.
Backplanes serve as the central nervous system in a great many electronic products from industrial controls to telephone exchanges. In a typical backplane, front-side connectors hold boards in place and conduct signals from board to board and to I/O connectors. Without carefully designed backplanes, engineers could not extend the state of the art in computer and communication equipment. Engineers can buy off-the-shelf backplanes for a variety of standard buses such as VME, VME64, VME64x, CompactPCI (cPCI), PCI Express and even for an older bus such as STD-32. If necessary, they can customize a standard backplane or create one of their own.
Put simply, to create a succesful interface for any complex product, you have to go beyond skin deep. You must be concerned not only with the layer that the user sees, hears, or touches, but also with the underlying software that ensures the interface is constantly available and quick to respond. Because, after all, nobody likes wimpy response times.
Thermocouples provide the key components of thermoelectric cooling modules. A thermocouple comprises a p-type and an n-type semiconductor element connected by a metal plate. Electrical connections at each end of the p- and n-type material complete an electric circuit. When a source supplies a current, thermoelectric cooling occurs. The thermocouple then "pumps" heat by cooling one side and heating the other by what is known as the Peltier effect.
I think is has finally happened. I have reached the tipping point in my purchasing of battery-powered portable electronic devices. That said, I should clarify that alongside many of my peers I am gadget-challenged. Still, I just can’t get that excited about applications like on-the-go streaming video and audio because the not-so-supercharged cloud hanging over all those cool devices...
Miniature solid-state inertial sensors are now in widespread use in passenger cars and SUVs with electronic stability control (ESC) being one of the primary high-volume applications. Tens of millions of gyros and accelerometers have been installed in vehicles since ESC first appeared in 1995. The primary ESC inertial sensors are a yaw sensor that measures vehicle turn rate and an accelerometer that measures side-to-side acceleration. The success of these sensors can beattributed to the use of extremely stable micromachined structures made from crystalline quartz and silicon with no moving parts and corresponding fatigue failure.
When compared to one time programmable (OTP) or read only memory (ROM) microcontrollers (MCUs), a flash memory-based MCU is distinguished by its ability to be reprogrammed. Many applications today need memory not only for storing the application program but also for storing data, which may need to be updated from time to time and must be retained in the application system, even after power off. For example, with a remote control, the user does not want to lose the preferred settings every time the battery is changed. External serial EEPROM can serve this purpose well, but adding another component to the system means higher system cost, a larger board footprint and degraded system reliability. An MCU with reprogrammable flash memory is a good choice for such an application, particularly if the application program needs a periodic upgrade to a newer version with enhanced features.
The Connect ME JumpStart development kit from Digi International includes a Comment ME module and development board. Software provides a 90-day evaluation version of Microsoft's Visual Studio 2005 Professional and the Microsoft .NET Micro Framework SDK plug-in for Visual Studio. This kit provides a quick and easy way to investigate .NET Micro Framework and its related tools and to build an embedded product that requires an Ethernet connection.
Liquid cooling provides a convenient way to remove heat from electronic components, boards, and systems. Its efficiency exceeds that of moving air, and liquid-cooling equipment does not require air channels throughout an enclosure. Some engineers may think of liquid cooling and picture leaking pipes and damaged electronics. Fortunately, liquid cooling has moved from the prove-it-to-me stage to routine use in high-end computers and military-and-aerospace equipment. So, just think of liquid cooling as a reliable and efficient way to move heat from one place to another. The removed heat can travel some distance to a radiator that dissipates the heat into outdoor air, municipal water, seawater or even another cooling system.
On a recent flight I talked with a software-engineering manager about the challenges of finding good embedded-system developers. She told me she has a team of 12 developers, but only three had proficiency with drivers, board-support packages, and boot-loaders. The other nine -- all good application developers -- lacked low-level coding experience. I asked if she had heard of the Microsoft .NET Micro Framework.