DALI DAPC OFF command

Question

We are working on DALI LED control gear type product. We are using TPS92515 as LED driver and its controlled through Iadj pin (analog dimming). Our issue is even if we give input zero (GND) to control pin (Iadj), there is 3mA current through LED and it is ON, but at low brightness. This means we cannot turn OFF the led by issuing DALI command DAPC 0 (OFF command), but DALI spec says LED shall switch off upon OFF command (Refer. Sec. 11.3.2, page 54, IEC62386-207:2016). Will this be an issue with DALI compliance certification? Any help would be appreciated.

Thanks

Answer 1

Yes that will be a compliance fail. The LED must go completely off when requested, so you must configure the circuit so that this occurs.

Also DAPC 0 is not the OFF Command, they are two different commands, although they must both result in the light output going to zero. DAPC 0 will fade to off using the current Fade Time setting, such that the transition to off occurs at the end of the fade time. Direct Arc Power commands have bit 8 in the 16 bit frame clear, all other commands have it set.

The Off Command is an immediate off with no fade. Bit 8 in the 16 bit frame is set, bits 7-0 are the opcode and are 0.