Timeline for How to adjust red brightness on MAX7219 with RGB LED
Current License: CC BY-SA 3.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 2, 2014 at 8:57 | answer | added | jnovacho | timeline score: 1 | |
| Dec 2, 2014 at 8:54 | vote | accept | jnovacho | ||
| Dec 1, 2014 at 18:16 | comment | added | Passerby |
Also There would be probably needed a resistor to protect the pins DIG 6 and DIG 7., no, just leave them disconnected, and don't turn the segments on.
|
|
| Dec 1, 2014 at 17:37 | answer | added | Passerby | timeline score: 1 | |
| Dec 1, 2014 at 15:41 | comment | added | Andy aka | With pleasure!! | |
| Dec 1, 2014 at 15:41 | answer | added | Andy aka | timeline score: 0 | |
| Dec 1, 2014 at 15:37 | comment | added | jnovacho | Got it. Can you please post this as an answer? | |
| Dec 1, 2014 at 15:33 | comment | added | Andy aka | 1 resistor controls the same current for all the outputs. If you need different colour currents then set one maxim chip to service all blue and others for green and red. | |
| Dec 1, 2014 at 15:30 | comment | added | jnovacho | I see. Then I'm missing something essential here. In the datasheet there is table, which shows how to select correct resistor, to set appropriate current through the LED. The table is based on desired current and LED voltage drop. So it is not possible to drive different colors at same instensity using 1 driver? | |
| Dec 1, 2014 at 15:27 | comment | added | Andy aka | Constant current drivers don't care about series resistors. Series resistors are used with LEDs when driven from a constant voltage source. | |
| Dec 1, 2014 at 15:12 | comment | added | jnovacho | I still don't see how is that link related to my question. | |
| Dec 1, 2014 at 14:49 | comment | added | Andy aka | Not normally - read the link I posted and note that LEDs should be driven with a constant current circuit. | |
| Dec 1, 2014 at 14:46 | comment | added | jnovacho | The MAX7219 is constant current driver. But each color has different drop voltage, so the resistance has to be adjusted. | |
| Dec 1, 2014 at 12:52 | comment | added | Andy aka | You ought to be controlling current into all the LEDs - driving with a fixed voltage is probably not recommended. See electronics.stackexchange.com/questions/141026/… - recently asked. | |
| Dec 1, 2014 at 12:43 | history | asked | jnovacho | CC BY-SA 3.0 |