EPSON real-time clock module RX8111CE provides flexible and stable low-power clock and timestamp functions for blood pressure monitors

Feb 12,2025
52 VIEWS

Today, as medical devices continue to pursue miniaturization, intelligence, and precision, electronic blood pressure monitors have gradually shifted from relatively fixed use areas such as hospitals to portable use at home. Therefore, there is a demand for products that are portable and have low power consumption. Blood pressure monitoring often requires multiple consecutive cycles, so accurate time recording is a very important function.

The timing inside the electronic blood pressure monitor will be used in the following aspects:

1. Accurately recording measurement time to assist doctors in judging changes in the patient's course of illness and determining subsequent treatment arrangements requires timestamps to be detailed down to hours or even minutes.

2. Regularly remind patients to take measurements or medication to avoid forgetting measurements and treatment, which may delay the condition.

3. When abnormal test data occurs, mark the record for easy and intuitive confirmation of disease progression.

Blood pressure monitors generally do not have networking capabilities, so they must have an accurate real-time clock to record time and provide a clock source. Due to the demand for product miniaturization, traditional discrete real-time clock circuits have a large volume and cannot meet the requirements of compact design well. The use of MCU built-in real-time clock modules also brings problems of power consumption and accuracy deviation. Therefore, how to provide a low-power backup clock while having an ultra small package is a significant challenge.

As a professional real-time clock module supplier, EPSON's real-time clock module RX8111CE is very suitable for the above application scenarios. It utilizes advanced packaging technology to encapsulate multiple functional modules such as high-precision 32.768kHz crystal units, I2C driver modules, automatic main and backup power management modules, etc. into an ultra small package with a size of only 3.2x2.5x1.0mm. No peripheral devices are required, greatly reducing the circuit composition and providing the possibility for further miniaturization of the product. Due to the built-in high-precision 32.768kHz crystal unit being calibrated before leaving the factory, the RX8111CE has a frequency offset characteristic as low as ± 11.5ppm, equivalent to 0.99 seconds per day. For applications such as blood pressure monitors that only require precision to the minute level, they can well meet their requirements for clock accuracy.

At the same time, thanks to the use of C-MOS technology, it has an extremely low operating current of up to 100nA at a working voltage of 3V, which is very friendly for electronic blood pressure monitors powered by small batteries with smaller capacities. The use of RX8111CE as a real-time clock source reduces the static current by an order of magnitude compared to the traditional real-time clock circuit's μ A level static current, greatly increasing the overall battery life.

As an off grid portable device, electronic blood pressure monitors also need to accurately add timestamps to each historical record without a network, accurate to the second level, making it convenient for users to refer to previous data in subsequent use. The RX8111CE integrates an 8-bit timestamp function internally, supporting recording from year to 1/256 second, which can flexibly and efficiently meet the timestamp requirements of electronic blood pressure monitors.