Individual pixels are aggregated into multiple Macro-pixel arrays, which in turn comprise a cluster. Typically a sensor will include up to four independent clusters whose output is averaged before conversion into a digital signal.
Key PPG challenges in the ear
Precision and reliability of measurements
Each biometric vital sign that can be detected through PPG requires different signal processing. This requires a raw signal with high fidelity to facilitate the extraction of the right information. The SB solution does this without applying special filters as the “filter approach” gives a better-looking signal but removes part of the information useful for accurate detection of signals such as the heart Interbeat interval (IBI) and Blood Pressure (BP)
PPG sensors’ power consumption is concentrated in two functional areas:
- The Analog Front End (AFE)
- Current to drive the illumination LEDs
PPG modules usually consume a lot of space as they need three components:
- The AFE
- The photodiodes
- The LEDs
High-Fidelity PPG Sensing
We have designed a high-fidelity PPG sensor in the form of a custom IC only 5.76 mm² in size, a fraction of any alternative, making it the ideal choice for incorporation into PPG-enabled earbuds.
Lowest Possible Power Consumption
As a result of our macro-pixel array’s extremely high sensitivity and a novel analog front end design, the amount of current needed to drive the LED sources in our PPG modules is greatly reduced.
Our custom IC integrates our advanced CMOS image sensor pixel array design, analog front end (AFE), and all interface and control circuitry into a single chip.
The Senbiosys chip architecture allows operation in various modes, reducing the need for additional components:
- ALS(Ambient Light Sensing)
- Proximity Detection