Portable medical electronics has seen tremendous growth and adoption in the recent years. More equipment variants are being introduced in the market by an increasing number of companies. The need of the hour is better mass producible designs which are low in complexity and provide acceptable performance so as to keep the cost of the device low. To achieve this, designers need to consider power efficiency, cost, form factor, and FDA certification of components, among other factors.
A typical portable medical electronic system comprises components like analog front-ends for data acquisition, amplifiers and filters for signal conditioning, analog-to-digital converters (ADCs) for signal and sensor data acquisition, buttons to accept user feedback, an MCU to execute algorithms, and a variety of interfaces such as an LCD display, USB port and so on. Traditional design methodologies bring together all of the needed functionality onto a PCB by way of individual components. This method increases the overall system BOM, PCB complexity, and design cycle. Using individual analog components also reduces analog IP protection as the system can be reverse engineered easily.
Portable medical equipment design and manufacture is also regulated by the Food and Drug Administration (FDA). This means that their design and construction must follow precisely documented processes, and performance must meet stringent documentation, development testing, production testing, and field maintenance requirements. One FDA regulation requires that the components used in a medical device have to be guaranteed to be available in production for the next five years. This provides an incentive for developers to reduce the overall number of components used to make FDA certification simpler.
Figures 1 and 2 show a typical blood pressure monitor (BPM) and a non-contact digital thermometer built using traditional approach.
Figure 1: Blood pressure monitor in traditional design approach Click on image to enlarge
Figure 2: Non contact digital thermometer in traditional design approach Click on image to enlarge