Hi, TI expert.
A customer has a question regarding the PD sensor when using the AFE4490.
The LEDs and PDs currently being used by customers are using the following products (Everlight).
- LED (RED, IR): IRR60-48C/L661/TR8 (660nm, 910nm)
- PD (Photo Diode) : PD60-48C/TR8
If you look at the left part of Simplified Schematic on the datasheet of AFE4490, you can see the LED and PD connection part.
The existing method uses a method of transmitting an LED by placing an LED on the upper surface of the finger and a PD on the lower surface of the finger.
(i.e., the LED on the nail side, and the PD on the opposite side of the nail (fingerprint))
The method to apply a new change this time is to put the LED and PD on the same side under the finger and reflect it to the PD.
(At this time, it is planned to use 2, 3 or more by connecting several PDs in parallel (increase)
(Question)
Q1) In this way, when connecting several PDs in parallel (increase) and using them, can the value received from the PD be measured by the AFE4490?
Q2) In addition, if the value received from the AFE4490 exceeds the AFE4490 measurement threshold, please inquire if it is possible to solve the problem by lowering the value received by the overall PD by adjusting the current value emitted from the LED.
Please confirm. Thank you.
