Renesas: RL78/L1A MCUs feature built-in bio-sensing AFEs for healthcare
Renesas Electronics announced the RL78/L1A Group of low-power 16-bit microcontrollers with a liquid crystal display driver that are ideal for battery-powered sensing devices used in healthcare applications such as blood glucose monitors, lactate analyzers, cholesterol analyzers, and other devices equipped with biochemical sensors. With the built-in analog front-end circuit for biochemical sensing, the RL78/L1A enables blood glucose and hemoglobin measurements with only one monitoring device. The RL78/L1A also delivers improved performance with high precision analog functions as well as longer battery life. System designers therefore can leverage the low-power and improved precision analog of RL78/L1A MCUs to create compact and lighter medical devices with extended battery life, which can help patients manage health conditions, such as diabetes, more effectively. Renesas will also offer sales of Renesas Promotional Boards which allow system developers to immediately evaluate the RL78/L1A functions.
In the healthcare field, when measuring a variety of vital signs, it is important to improve both the efficiency of analog functions and digital processing performance within the MCU itself.
The RL78/L1A Group incorporates analog switches that were previously uncommon in MCU AFEs. By combining switches with a built-in A/D converter, it is possible to switch the measurement circuit including external circuits in software when the target is changed. For example, in devices like blood glucose monitors, adjusting the measurement precision in response to differences in the blood components has become an issue. Flexible methods, such as alternating measurements between components such as hemoglobin and the blood glucose levels, could address these issues.
Renesas provides reference software that makes it easier to improve precision by using the internal AFE functions, such as 12-bit A/D converters, rail-to-rail operational amplifiers, internal reference voltages, and 12-bit D/A converters. In addition to improving device precision, this software can provide improved stability, contributing to improved precision analog functions in user systems.
Renesas has made various circuit improvements to the AFE, enabling a significantly lower supply voltage. These improvements allow the measurement circuit, which is the main function for end products such as blood glucose monitors, to operate down to the very end of the system’s effective battery life. While earlier analog circuits could only operate down to 2.4 V (Note 3) and then stopped, these new products can be used fully down to 2.0 V.
The RL78/L1A is now available in six product versions, with 80- and 100-pin packages and with internal flash memory capacities ranging from 48 KB to 128 KB.