An optical sensor for heart rate monitoring for wearable devices such as sports bands and smart watches was designed by ROHM Semiconductor to meet the needs for low power consumption. BH1790GLC optical sensor incorporates an LED driver and green light detection photodiode.

The optical filter extends battery life while reducing the effects of IR rays by 10x versus conventional products. High-quality pulse signals can be acquired even in outdoor environments with a strong IR presence, or under intense movements (i.e., sports).

The device detects high-quality pulse signals using low VF low-brightness LED elements, eliminating the need for DC/DC circuits for LED power supply. This reduces the mounting area by 30 percent, lightening the development load.