Embedded technology and application for portable medical monitoring equipment
introduction
Today, with the booming of electronic technology, the government and medical institutions at all levels are working hard to improve the medical system to better serve patients. After the application of embedded technology reaches the medical industry , patients can have more choices, choose the treatment and treatment that suits them, choose to stay at home, or go to the hospital or doctor's office. The medical industry has leveraged the advantages of a portable, remotely connected medical monitoring system. Such monitoring devices include electronic blood glucose meters, portable bedside monitors, portable electrocardiogram (ECG) systems, and even more sophisticated medical monitoring systems.
Since 2008, more and more good news has appeared in the field of medical electronics. Both Germany and Australia have clearly stated that they will increase their investment in the fields of child care and universal health care. Developing countries with large populations such as China and Mexico are also undergoing medical reforms that have attracted worldwide attention. These government-level inputs will increase the demand for medical electronics in society as a whole. In addition, there are some factors that will have an impact on the medical electronics market.
The global population is becoming more and more aging, and these aging populations have a very large demand for medical care.
There is growing recognition of the concept of disease prevention and early detection and early treatment, which will facilitate the need for basic medical instruments such as x-ray, CT, positron emission tomography (PET), MRI and ultrasound.
The upgrade and update of medical instruments will also bring new demands to the market, such as the change of the screen of ultrasonic instruments from black and white to color.
All of the above factors have a great impact on the technical direction of medical electronic devices. Portable medical electronic devices with relatively low cost compared with large-scale devices have shown unprecedented vitality under the demand. For example, a sphygmomanometer or a blood glucose meter that can be carried with you, a ventilator or an electrocardiograph that can be used in a home or a small social hospital will inevitably have an increasing market demand.
"Portable" medical electronic devices are increasingly demanding portability while addressing the flexible transfer of data, and to maintain the quality and real-time nature of the acquired data. There are two main types of portable devices. One is a mobile (handheld) device, such as a product for patient monitoring, such as a product that measures pulse, blood pressure, and other signs, which can be easily carried at any time, and it is necessary to ensure that the battery has sufficient battery life, at least one day for the doctor to visit. No need to charge inside. The other ones are not necessarily portable, but they are low-cost, simple devices that are generally used in hospitals with simple equipment. This of course brings design challenges, not just the size of the equipment, but also the internal electrical parts need to be innovative.
An entire system of portable medical monitoring equipment has five basic parts: data acquisition, data transmission, data processing, human-machine interface, and power supply. The ZTE-MEDiX series focuses on the five components of the monitoring system and uses targeted new technologies to optimize the performance of medical monitoring equipment.
　　 Battery and power management
Display and Human Machine Interface (HMI)
Biosensor interface and bus
Data exchange interface
Central processing unit and data operation efficiency
Reliability design for portable applications
Battery and power management
Power management techniques and low power consumption should not be exactly the same. The ARM product itself has relatively low power consumption, but only with the perfect power management technology, the endurance of the product can be maximized. While limiting power consumption, it is necessary to balance the system's processing data requirements. New power management techniques and power supply topologies implement several power-level and standby modes to help the system achieve high levels of performance with low levels of power consumption.
ZTE-MEDiX manages system standby, sleep, and wake-up transitions to improve overall system performance to create a system that combines both aspects of performance. If the CPU is only active when it needs to be processed, the average system power consumption will remain low, and the peak will only be reached when the CPU wakes up. Improve system usability by implementing multi-level power management.
Example 1: The ZTE-MEDi27 main board has one working state and four levels of sleep state. The power consumption of the main board can be reduced from 1030mW at full speed to less than 20mW in deep sleep. With powerful power management technology, users can not only get the longest battery life, but also reduce maintenance costs (reduce the frequency of maintenance and extend battery life).
Example 2: ZTE-MEDi27 main board with a 10-inch LCD monitor personal monitoring system, powered by two lithium-ion batteries (2000Ma@8V). After 30 seconds of unattended operation, the system enters the power-saving state and any external operation is activated. Can be used continuously for more than 12 hours without charging.
Display and human interface
Whether displaying patient temperature or electrocardiogram (ECG) results or other physical signs, the display is an important performance feature.
Medical monitoring equipment, especially multi-function monitoring equipment, such as 6-channel, 8-channel equipment, requires a large display screen to clearly display the patient's vital signs. Large-size screens need to consume more battery power, so the ZTE-MEDi27 embedded motherboard has specifically added LCD energy-saving circuits, and the LCD can enter the active power-saving mode at the right time. In addition, it is recommended to use the motherboard with high quality and low power consumption LCD to achieve better display performance.
For example: ZTE-MEDi27 embedded motherboard supports TFT LCD, the maximum resolution is 800*600, and it can also be connected to VGA device at the same time.
With the development of portable ultrasound equipment from monochrome to color, from 2D images to 3D and 4D, the number of channels of ultrasound equipment will be greatly increased, which requires a high-performance beamforming architecture, and with the user's resolution of the ultrasound equipment image and As the demand for time resolution increases, the amount of computation required by the device will increase greatly, placing higher demands on the graphics processing capabilities of the central processing unit. The ZTE-MEDiX series offers more powerful graphics processing power than traditional DSP/FPGA graphics processing solutions, and greatly shortens the product development cycle, giving patients the opportunity to enjoy the gospel of advanced technology earlier.
The touchscreen (TouchPanel) is a key factor in simplifying the use of portable electronic devices, which further reduces the size of the device by eliminating the need for a traditional keyboard. The touch screen combines with the function selection of the software menu to enhance the human-computer interaction ability of the medical product , and the user-friendly interface is more convenient for the patient or the medical staff to use. An important factor to consider when designing touch screen functionality is the electrostatic (ESD) processing power of the chosen solution. If the circuit does not eliminate the energy generated by static electricity, this energy can cause damage to the monitoring system. Other factors associated with touch screens are resolution, screen size, conversion type and speed, sensitivity, and overall power consumption.
Biosensor interface and bus
All designers who design medical monitoring equipment choose the widely used UART sensor interface and select mature bus technology such as CAN. In addition, local medical electronics manufacturers often have fewer R&D personnel, which has no advantage over the development teams of hundreds of foreign medical electronics manufacturers. Therefore, local developers should first target equipment that can reduce costs and generate benefits. Development. The ZTE-MEDiX series provides designers with multiple UART interfaces (2~11, different models). ZTE-MEDiX-based portable medical monitoring devices can support multiple biosensors simultaneously. On the bus side, the ZTE-MEDiX series provides 1~2 CAN buses. SPI, I2C, I2S, and GPIO are also available as biosensor interfaces.
Example: In the pulse oximeter design, through the GPIO and responsible for controlling and coordinating the normal operation of other circuit modules, the collected blood oxygen signal is processed by data and sent to the display. ZTE-MEDiX's processing capabilities, sampling rate, sampling accuracy, power consumption, real-time requirements and other indicators fully meet the system requirements. And can provide an extended RS232 interface to work with other devices.
Data exchange interface
Medical monitoring equipment can generate large amounts of raw data. Saving data and processing trends, identifying changes, providing feedback, supporting the ability to connect to larger systems, and performing diagnostic algorithms are often important functions of the system controller.
The medical electronics data interface migrates from wired RS232 interfaces to wired and wireless Ethernet connections, and short-range and longer-range wireless connections. Hospitals can use these new interfaces to connect all devices in the hospital and in the patient's home. When the patient returns home from the hospital, he or she can be remotely contacted by a wireless sensor on the body, which is connected to the monitor of the home security system. The entire system is connected to an Ethernet or medical call and can be monitored privately at home.
Wireless interfaces such as Bluetooth and GPRS can also be used here. A wireless solution for the Gene Wireless Digital Module can also be used. In addition to power consumption, data rates and distances are two important elements in choosing a wireless interface. ZTE-MEDiX series medical motherboard, integrated wired RS232 data port, USB interface and Ethernet interface, unlimited GPRS and wireless data transmission interface; ZTE-MEDiX also integrates SD card for data transmission.
In this case, the limitations of traditional medical monitoring equipment distances are completely broken and the data rate is maximized. If monitoring uses only a few sensors, the distance is more important than the data rate. Finally, the selection scheme must control system power consumption.
Central processing unit and data operation efficiency
When medical device manufacturers choose the motherboard solution, they will follow two principles: one is the mainstream solution of the market; the other is easy to upgrade and replace. Mainstream solutions and strong suppliers are more secure in terms of continuous supply. At the same time, as far as possible in the design, a standardized, continuous product line is adopted. This principle can quickly find alternatives when it comes to supply problems such as production suspension.
The ZTE-MEDiX series uses ARM-based CPUs. ARM is the IP (intellectual property) provider of embedded RISC processors, which provide ARM processor cores (such as ARM7T, ARM9T and ARM10) for ARM architecture processors. Each semiconductor company redesigns on the basis of the above processor cores, embedding various peripherals and processing components to form various MCUs. Current ARM core-based chips account for 75% of the embedded processor market. As a processor of the embedded system, ARM has the characteristics of low voltage, low power consumption and high integration, and is open and expandable. In fact, the ARM core has become the processor core of choice for embedded systems.
The ZTE-MEDiX series currently uses three main CPU frequencies, including 200MHz, 400MHz and 520MHz, to meet a variety of portable medical monitoring applications.
Reliability design for portable applications
The range of applications covered by portable medical devices is becoming wider and wider, and the reliability design of products must take into account the various needs that may be considered. Medical imaging equipment needs high-quality images in the future, and at the same time, the number of frames per second is also increasing, so high-performance devices must be selected. The future development trend of ultrasound equipment is low power consumption, high performance and miniaturization, so the integration of the device should be considered. In ECG (ECG) design, attention should be paid to board-level electromagnetic compatibility. CMRR (Common Mode Rejection Ratio) is an important indicator that can improve monitoring accuracy and protect patients. Low-jitter clock signals are important in high-speed signal processing, which optimizes SNR (signal-to-noise ratio). To ensure that the device is compatible with other medical devices, strict security testing must be performed.
in conclusion
In the future, there will be more innovative medical equipment, and all kinds of large-scale medical equipment will hope to turn to portable and miniaturized. Just stand in front of the machine and you can see the doctor in front of the LCD monitor. Virtual doctors are anywhere in the world, and we can see a doctor or know about our health while sitting at home, in the office, or on vacation. Just today, portable medical devices and surveillance systems provide medical support anywhere, anytime.
Medical electronics have a longer life cycle than consumer electronics, and small home medical electronics typically last 3-5 years. Although the life cycle is long, medical electronics require more attention to design than consumer electronics in terms of accuracy and ease of use.
To help medical device manufacturers develop these innovative products, the ZTE-MEDiX series continues to innovate, continuously improve performance, integrate embedded cutting-edge technologies, and simplify the secondary development process. For greater success, the ZTE-MEDiX series is proactively close to the features and needs of portable medical products, understanding the limitations of various portable device size and power budgets. It can help medical equipment manufacturers shorten the development cycle, compress design costs, help patients enjoy the industrialization of new technologies earlier, take the initiative to master their own health, and enjoy a wonderful life.
Rushan Jinguo Food Co., Ltd , https://www.jinguofood.cn