Ivanlee Posted April 10, 2021 Report Share Posted April 10, 2021 Hi, all I'm using a PCA9685 with a pinout board like Adafruit's. I'm trying to run a bunch of LEDs at 20 mA, and the chip is supposed to be able to source 10 mA and sink 25 mA. I understand that to have it Source, you connect the LED between the PWM and GND pins and to Sink you connect it between V+ and PWM. I've tried both ways and using a multimeter and a red LED I get 12.5 mA. Why is it not 25 in Sink? Also, why do I get 12.5 on Source mode as well? Is there anyone have ideas of it? if possible a simple explanation would be nice. Many thanks.☺️ Quote Link to comment Share on other sites More sharing options...
HarryA Posted April 10, 2021 Report Share Posted April 10, 2021 That is a complex beast! Given: "Each LED output can be off or on (no PWM control), or set at its individual PWM controller value. The LED output driver is programmed to be either open-drain with a 25 mA current sink capability at 5 V or totem pole with a 25mA sink, 10 mA source capability at 5 V." If you are using the PWM control the meter would not show the peak currents to the LEDs. Other then that it is difficult to help troubleshoot something that requires programming. Quote Link to comment Share on other sites More sharing options...
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