Authors: Kevin Fu, China Regional Marketing lead, Connectivity, Renesas and Rossella Guiot, Central Marketing manager, Connectivity, Renesas
Diabetes mellitus, which affects more than 10% of the world's population (source: International Diabetes Federation), poses significant health risks due to its wide range of complications and the lack of a simple cure.
Continuous glucose monitoring (CGM) has proven to be a game-changer for patients, improving their quality of life by enabling them to make informed decisions about their daily routines.
CGM measures glucose concentration in the interstitial fluids of the skin (Fig. 1). It is therefore less invasive than blood glucose measurement and can be comfortably worn on the patient's skin for several days.
Figure 1. Image from DiabetesWise.org. The image depicts the layers of skin over the blood vessels and shows how reliable glucose information resides in the interstitial fluid, beyond the blood.
Data collected by CGM systems every few minutes can be transmitted to a medical reader or smartphone and then shared with healthcare facilities for recording and analysis by professionals. Furthermore, the continuous flow of data from connected patients is driving the development of advanced AI-based predictive models for more effective diabetes management and research purposes.
MCG's technology research focuses on developing more precise, safer, miniaturized, durable, and cost-effective solutions. The goal is to ensure long-term accessibility and widespread use, with electronics playing a key role in overcoming these challenges.
Most commercial CGM systems use electrochemical amperometric sensors placed on the patient's skin. These sensors measure a small current proportional to the glucose concentration, which is then processed by an analog interface circuit (AFE) and converted into a digital signal. This signal is processed by a microcontroller (MCU) and transmitted via Bluetooth Low Energy (BLE) to a medical reader. The system is powered by a disposable button cell battery.
A recent reference design, developed by Renesas Electronics Corporation and Xmoore Microelectronics, showcases some of the latest advances in CGM technology. The design features a compact and efficient system that includes an AFE, a BLE SoC, and a small external flash memory for data storage. The BLE SoC not only processes glucose data but also wirelessly transmits it to a medical reader or smartphone, making the system highly convenient for both patients and healthcare professionals.
As shown in Fig. 2, the reference design features an ultra-compact solution where both the BLE SoC and the AFE are powered by a 1,5 V silver oxide cell without the need for an external DC amplifier, representing a significant improvement in terms of size and power efficiency. The entire system fits into a space of just 18 mm, including the battery, allowing CGM manufacturers to create smaller and thinner skin patches than those currently available on the market. This miniaturization reduces the bulk and discomfort often associated with traditional CGM devices, improving patient comfort and encouraging better adherence to glucose monitoring protocols. Furthermore, the use of a low-voltage commercial battery contributes to a lower overall device cost.
Figure 2. The reference design incorporates an Analog Front-End (AFE) developed by Xmoore and a Bluetooth® System on Chip (SoC) supplied by Renesas Electronics.
This cost-effective and compact solution, as also shown in Fig. 3, makes the reference design highly competitive in the market. The smaller form factor, coupled with the power efficiency of both the BLE SoC and the AFE, ensures that the CGM system remains affordable without compromising functionality or performance. This cost-effectiveness is especially important for making continuous glucose monitoring more accessible to a wider segment of the population, particularly in regions where insurance coverage may be limited or where patients face financial barriers to obtaining expensive medical devices.
Figure 3. The system operates on a standard 1,5 V battery and can be integrated into a compact 18 mm patch, equivalent to a US dime.
The system operates on a standard 1,5V battery and can be integrated into a compact 18mm patch, equivalent to a US dime.
By improving accessibility to diabetes management tools, this technology can play a pivotal role in reducing long-term health complications associated with diabetes. As more patients gain access to reliable and cost-effective CGM systems, the burden of diabetes-related health problems could be significantly reduced, resulting in improved health outcomes and a better quality of life for millions of people worldwide.
In conclusion, the new CGM reference design from Renesas Electronics and Xmoore Microelectronics offers an exciting advancement in diabetes care. The combination of miniaturization, energy efficiency, and cost savings makes it a highly competitive solution in the market. By providing increased patient comfort and reducing overall costs, this reference design has the potential to expand access to transformative diabetes management tools, thereby improving the prevention and management of diabetes mellitus globally.
The Renesas DA14531 ultra-low energy Bluetooth® system-on-chip incorporates a 2,4 GHz transceiver and an Arm® Cortex®-M0+ microcontroller, and is packaged in a compact 3,0 mm x 2,2 mm package. This configuration extends battery life by enabling continuous operation even during the discharge cycle of a 1,5 V battery, when its output voltage has dropped below its nominal value. The DA14535 is also an option when more RAM is needed.
XMOORE AFE XMB1000 works with 2- to 4-terminal electrochemical sensors and integrates a 0°C to 50°C temperature sensor. The device can operate with a supply voltage as low as 1V without performance loss and is housed in a 2,0mm x 2,0mm pitch BGA package with very limited passive components.
