They eat 150mA peak current, and 120mA when reading. They are not always active, only when the phone is expecting an authentication.
They are never alone, but packaged with a capacitative touch sensor, so when the touch is triggered the fingerprint sensor starts reading.
Infinix smartphones vibrate when a successful fingerprint reading is achieved. This kind of feedback uses more current than the sensor itself!

Compared to other subsystems in a phone like Wi-Fi(300mA peak), screen(100–400mA continuous) and bluetooth low energy(15mA continuous), the fingerprint scanner is NOT an energy hungry sensor.

http://www.infinix.club/ng/forum/687/937509

felasey1:
They eat 150mA peak current, and 120mA when reading. They are not always active, only when the phone is expecting an authentication.
They are never alone, but packaged with a capacitative touch sensor, so when the touch is triggered the fingerprint sensor starts reading.
Infinix smartphones vibrate when a successful fingerprint reading is achieved. This kind of feedback uses more current than the sensor itself!

Compared to other subsystems in a phone like Wi-Fi(300mA peak), screen(100–400mA continuous) and bluetooth low energy(15mA continuous), the fingerprint scanner is NOT an energy hungry sensor.

http://www.infinix.club/ng/forum/687/937509

dont understand oo