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Adding External LEDs

Category: Hardware
Product Number: ADPD188GG

Hello everyone,

I'm planning to connect external LEDs to LED2 and LED3 pins. The absolute maximum voltage rating for these pins in the datasheet is 3.6 V and my LED power supply (anode pins) is set to 4.3 V. I have two questions:

  1. What should be the maximum forward voltage of the chosen LEDs? Is this critical? Since the anode of the external LEDs is connected to 4.3 V and typical LEDs have a forward voltage (VF) ranging from 1 V to 3.5 V, it seems that the voltage on the LED driver pins will not exceed 3.6 V. Is this understanding correct?

  2. Since the anode of these LEDs is connected to 4.3 V, assuming a forward voltage of 2.3 V and a forward current (If) of 20 mA, does the APDP188 control the current flow through the LED, or should I include a resistor to limit the current? I'm asking because the datasheet mentions that the current can be as high as 200 mA, and adding a resistor may result in a significant voltage drop. (p27, DETERMINING CVLED).

Thank you for your assistance.

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