Helvar LL1-CV-DA: DALI dimming for constant voltage cove lights

Helvar's answer to dimming LED strip on DALI is a two-part solution: a constant voltage driver for power and the LL1-CV-DA driver extension for control. We introduced it in January 2015 for indirect cove and decorative lighting, and it is still in Helvar Components' range today.

How the two parts fit together

LED strip runs at a fixed 12 V or 24 V, so it needs a constant voltage driver rather than the constant current drivers used for downlights and panels. Most CV drivers have no dimming input. The LL1-CV-DA goes between the driver and the strip: it takes the 12 to 24 V DC output, listens to DALI, and dims the strip by pulse width modulation. Duplicate terminals let you connect strip runs in parallel, and the unit has an integrated strain relief for mounting outside a luminaire.

Helvar lists its own CV drivers as the partners, for example the LL1x75-E-CV24, which names the LL1-CV-DA as a compatible product.

Dimming quality

The DALI dimming range runs from 0.1 % to 100 %, which matters in hospitality and residential coves where the lights often sit at a few percent in the evening. Helvar quoted a 1 kHz PWM frequency when we first wrote about it; the current product data lists 2 kHz and compliance with IEEE 1789-2015, the recommended practice for limiting flicker.

Why 24 V and low standby matter

For the same wattage, a 24 V strip draws half the current of a 12 V one, so voltage drop and losses along the run are lower and runs can be longer before the far end dims. Standby power on the LL1-CV-DA is below 0.1 W, which counts in buildings where cove circuits spend most of the day switched off over DALI but still powered.

The full datasheet is on Helvar Components' LL1-CV-DA page, and the part is on our LL1-CV-DA product page. If you have a cove schedule with strip lengths and wattages, send it over and we will size the drivers and extensions.