U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

Silergy Corp.

Arjan Van Den Berg

Tobias Georg Tolle

Hendrikus Johannes Janssen

Lambertus J Bouwman

Hendrikus Johannes Jacobus Domensino

Hendrik Jan Boswinkel

Tobias Sebastiaan Doorn

Lambertus J M Bouwman

There is disclosed a driver for driving a series arrangement being a variable number of strings of LEDs wherein each string has a capacitance connected in parallel with the respective string; the driver comprising: a controllable current source adapted to be connected in series between the series arrangement and a rectified AC supply to and source a controllable current (Istr) through the series arrangement; and a current source controller adapted to control the controllable current source; wherein the current source controller is operable to source a relatively lower current (I') when a difference (VstrA) between the voltage across the series arrangement and the voltage of the rectified AC supply is relatively higher and a relatively higher current (I) when the difference is relatively lower. Associated driver circuits and lighting circuits, and methods are also disclosed.

Method for dynamic reduction of LED current in LED driver, and associated drivers, driver circuits and lighting circuits

A power supply arrangement having a DC/DC converter is presented that includes a control loop on the primary side of the isolation transformer within the DC/DC converter to control the voltage on the primary winding. The energy transfer across the isolation transformer is effected via control switches that alternately charge and discharge a capacitor through the primary winding. The control loop preferably adjusts the duty cycle of these control switches to control the voltage on the primary winding.

Power supply arrangement comprising a DC/DC converter with primary-side control loop

A pulse igniter for a discharge lamp has a transformer with a primary winding coupled to a first capacitor and a switching element and a secondary winding shunted by a series circuit of a diode and a second capacitor at its output. As a result, the generated ignition voltage is rectified and applied to the lamp for a relatively long time interval, resulting in improved ignition behavior.

Pulse ignition apparatus for a discharge lamp

A DC/DC converter of the flyback/forward converter type includes a switch (S), a transformer (T), a first diode (D1), a first capacitor (C1), a second diode (D2) and a second capacitor (C2). The first and the second capacitor are arranged in series between the output terminals (K3, K4) of the DC/DC converter. The DC/DC converter has a high efficiency and is very suitable for operating a lamp with a DC current.

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Nijmegen, Netherlands

Arjan Van Den Berg