Eldolab Holding B.v.

Antonius Jacobus Maria Cremer

Machiel Slot

A method of driving a number of high-power light-emitting diodes (LEDs) which are divided into two or more groups, each group being separately energizable by a corresponding one of the power supplies, includes: a) energizing or deenergizing a supply current from the corresponding one of the power supplies into a first one of the groups; b) waiting for a predetermined wait time period; and c) repeating step a) and b) for a second one of the groups. Besides, a supply unit for performing the method comprises a control input, a control unit, and at least two power supplies for correspondingly feeding the two or more LEDs groups.

Methods and apparatuses for operating groups of high-power LEDs

An energy-efficient, compact and cost-effective solution for driving a number of high-power LED groups for lighting applications includes using a single switching power supply together with LEDs connected in series and/or in parallel and pulse width-controlled switches in parallel across the individually controllable LED groups. If the switch of an LED group is ON, the LED group will not light up. If the switch is in the OFF position, the full current of the power supply will pass through the corresponding LED group.

The object of the invention is to implement an energy-efficient, compact and cost-effective solution for driving a number of high-power LED groups for lighting applications, by using a single switching power supply together with LEDs connected in series and/or in parallel and pulse width-controlled switches in parallel across the individually controllable LED groups. If the switch of an LED group is ON, the LED group will not light up. If the switch is in the OFF position, the full current of the power supply will pass through the corresponding LED group. Another aspect of the invention is the restriction within the drive protocol, according to which but a single switch is actuated at any one time within a particular time interval. This aspect guarantees a minimum time interval between each individual actuation event. Another aspect is the derating of the power supply in those phases where not a single LED group is ON. In the event of all the switches being closed (all LED groups OFF) the power supply can be derated (or turned off). A further aspect is the use of an elevated current setting of the power supply with the simultaneous restriction of the ON cycle by means of pulse width modulation. The power supply is set to the maximum instantaneous peak current of the LED, while maximum pulse width drive guarantees a maximum of the average LED current, cycle time being left over as a result, thus enabling more LEDs to be driven at a given supply voltage.

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Oisterwijk, Netherlands

Antonius Jacobus Maria Cremer