Design considerations for portable medical electronic devices

- Aug 14, 2017-

With the onset of diabetes and heart disease and other serious diseases surge, accompanied by the accurate portable patient monitoring system, which including cholesterol, blood, blood pressure monitoring, and other portable medical devices. And, more importantly, device users are able to follow up the results of individual tests. Technological advances in the mobile phone industry have created fairly uniform standards and dimensions that make the product more accessible and easier to use for consumers. For patient monitoring devices, many simplifications are needed to achieve this stage of simplification.

According to the evolution of mobile phones, there are a number of clear trends that all portable devices should take into account. The following topics will be discussed: the advantages of the I/O standard, the USB port, the durability of ESD protection, and the use of analog switches to improve the functionality of FPGA and ASIC in medical devices.

With the increasing popularity of ASIC and FPGA, it seems natural to use them as the core of the device. The initial cost advantage of this decision can be easily calculated, but it is important to consider the various devices needed to integrate the device into an integrated device. The core operating voltage of a portable design is often 2.5V or less, which is very useful when working off batteries, allowing a boost power management device to maintain efficiency with minimal voltage differences. However, to achieve this low core voltage and rich gate number in ASIC technology is not without shortcomings, instead of these devices are easily influenced by the high voltage peak, the peak is called electrostatic discharge.

For such a case, analog switches are ideal choices. From video to data, I/O ports, and even audio headsets and other connector interfaces, analog switches are suitable for applications. Fairchild is the leader in the switch market, which can easily support 8kV HBM protection, even more than 10kV; bandwidth from several thousand to more than 1GHz of the latest video switch series. Not only can they protect ASIC, they can also add functionality to a chip level package. Their functional language is the term standard switch, that is, the SPST corresponds to a monopole single throw switch, and the SPDT is a double throw. The number of switches in a single package can be 1~4, supporting single ended and differential interfaces. Adding analog switches can bring about a variety of ASIC changes. For example, if there are two separate sensors in a medical device, a SPDT switch can be used to switch between the ASIC and each sensor. Headset port can use special switch to switch between two sound generator, or provide undershoot protection, to avoid minor explosions in will hear the headset into jack.

An important feature of all portable devices is the ability to add storage. There are many standards for memory cards, and some of the most common standards are SD, MicroSD, and XD. To avoid restricting the design to the use of a memory card, the use of analog switches enables the addition of more than two memory card slots. Because you only have access to a memory card each time, you do not need to use the dynamic hub type switch. SD card development to be able to integrate applications into the actual memory card. Applications include Bluetooth, Wi-Fi, fingerprint scanners, and GPS, which continues. Increasing the SD card functionality in portable designs can benefit from the development of these cards.

Because the composite video output allows the user to review all records in full, or to playback video in full size. Graphics processing is often an option offered by ASIC vendors, but a driver cable for video drives is also required. Fairchild's latest FMS6501 is an ultra small integrated video filter and line driver that provides ESD protection.

Whether or not there is a video port, this device must have input and output external data. If this port is also the main port of the battery charge, it will be more ideal. The universal serial bus standard of the I/O port, which is widely available, is just right to do so, and has almost replaced the previous serial connection. Please refer to the USB standard to ensure compatibility with the power technical specifications. It is possible to set up a current limiting device on the port, such as Fairchild's Intellimax device.

Medical consumer products are easy to use, durable and accurate. The portable technology potential has emerged, and in today's mobile phone industry has been verified, that portable device only needs to maintain as little as possible. The medical profession must follow a similar path of development, such as an integrated hematology analyzer, a thermometer, and a blood pressure device. When a medical device is combined with the PC's analytical power over the USB port, the patient is able to perform precise tests and track the entire process. Understanding these small signal areas, cutting-edge IC, will be able to develop better end - of - the - line medical products.

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