What you’ll learn:
- How to design medical devices with small and robust MCUs.
- Understanding the role of MCUs to meet the low-power design requirements of compact medical devices.
- The role of core independent peripherals (CIPs) in MCUs.
In the last year, the global health crisis has turned our healthcare system on its head—shifting what was once a communal culture to what’s now a more remote and physically distanced future. Despite the recommended safety measures, many people still postponed medical appointments and medical care to lessen their risk of virus exposure.
As a result, remote medical care rapidly evolved, providing a safer and more convenient option for patients, while also helping to reduce strain on our overwhelmed healthcare system. In fact, the American Hospital Association reports that 76% of U.S. hospitals connect with patients and consulting practitioners at a distance using technology.
Looking forward, it’s clear that remote medical care using smart, portable medical devices is the future of preventative, chronic, and routine healthcare. As such, the demand for such medical devices will escalate, impacting the future of healthcare. Smarter patient diagnostic and delivery systems, like in-pocket nebulizers or Bluetooth-connected thermometers, can support a healthier population remotely. However, their compact design relies on embedded technologies that bring a high level of sophistication to a small space.
So, as we prepare for the future of remote medical care, what’s the best approach when designing a portable, connected medical device?
Small and Robust MCUs
Start by designing with small and robust microcontrollers (MCUs). As a key component of an embedded system, MCUs are used to control the application functions needed in portable medical devices, like sensor signal acquisition for biometric measurements and closed-loop control.
By choosing an MCU that automates application tasks, it can help simplify the implementation of complex control systems even further, enabling simultaneous tasks in a single MCU. With such functions, MCUs can play an essential role in portable medical designs. When choosing the right MCU for your portable medical device, make sure it offers the following capabilities spelled out below.
Portable medical applications require an MCU that offers different power-management modes to balance performance and power consumption to extend the battery life. Portable devices must be designed to consume minimal power and run for years on a single battery.
The key to long battery life is to operate with the lowest current consumption by reducing system activity when it’s not needed. Flexible levels of configuration allow the system to consume minimal power for the tasks at hand, often without supervision from the central processing unit (CPU). Features like idle, doze, or sleep modes provide power saving to reduce active power consumption. With these low-power modes, battery life is extended for portable medical devices, while reducing current consumption, power dissipation, and costs.
Devices for remote medical care are meant to be used in peoples’ homes and on-the-go. Portability and small physical size are major factors that contribute to the benefit derived from these devices. The smaller and more portable such a device is, the more easily it can be included in the patient’s daily routine and the more likely it will improve outcomes.
Compact and small medical devices can only be achieved by optimizing board space throughout the design process, starting with system architecture. An MCU with an intelligent combination of on-chip digital and high-accuracy analog peripherals reduces the need for external components, all while saving board space and cost.
For example, highly integrated MCUs like Microchip Technology’s PIC18-Q40 are equipped with advanced analog with filtering capabilities for telehealth vital-sign measurements. In addition, built-in communication protocols, including UART, SPI, and I2C, enable connectivity in telehealth designs.
Such on-chip analog peripherals enable designers to bring functions typically off-chip onto the MCU to improve system response and reduce bill-of-materials (BOM) costs. MCUs offered in small packages also reduce the printed-circuit-board (PCB) footprint, enabling developers to create extremely compact designs for smaller end products like handheld nebulizers or syringe pumps for medication delivery.
Core Independent Peripherals
Core independent peripherals (CIPs) are designed to implement a variety of application tasks that don’t need constant interaction with the CPU. These hardware-based peripherals consume minimal power, require little to no code, and less RAM and flash memory to implement the same functions in software.
MCUs with CIPs significantly streamline the implementation of critical tasks for applications like smart medical devices. That’s because they’re designed to automate system tasks with no code or supervision from the CPU core, reducing the amount of code to write, debug and validate.
CIPs communicate with each other, which helps increase system performance and responsiveness, while also reducing power consumption. Thus, the CPU is free to focus on other system tasks or go to sleep. In turn, complex tasks are easily implemented at the same time as other more routine tasks. By offloading time-critical and core-intensive functions from the CPU, CIPs simplify the medical design development process by reducing the component count, code size, development time, and power consumption.
When choosing the right MCU for your next medical design, look for one that offers CIPs like timers, a simplified pulse-width-modulation (PWM) output, an analog-to-digital converter (ADC) with computation, a configurable logic cell, and direct memory access (DMA). In addition, MCUs like the PIC18-Q40 also bring interconnection capabilities that allow for near-zero latency sharing of data, logic inputs, or analog signals without additional code or interrupting the CPU. This gives developers the ability to create a customized medical device with improved system response, precision control, and lower power consumption.
To help support a seamless development process, while also getting products to market faster, designers should couple small and robust MCUs with software-development tool suites. These development suites provide a straightforward process for configuring basic functions on an application, simplifying and accelerating code development by using factory-validated code libraries.
With these tools, designers can easily customize combinations of CIPs in a simple graphical user interface (GUI) environment and generate application code without having to read through datasheets. This will enable a medical design to move from prototype to production in a matter of months, helping today’s designers better meet high market demands and supply shortages.
The global demand for smart medical devices will continue to grow with the ongoing need for remote medical care. Designing compact, power-efficient, and portable medical devices will be key to the future of our healthcare, and MCUs that can bring a high level of sophistication to compact medical designs will serve as a foundation for these critical device designs.
To learn more about meeting these demands for portable and compact medical design solutions, visit www.microchip.com/medical.