Abstract: A switch mode power supply is described including a primary side for coupling to a mains supply and a secondary side for coupling to a device, an isolation transformer comprising a primary coil and a secondary coil and arranged to isolate the primary side from the secondary side, and a noise filter coupled between a primary ground at the primary side and a secondary ground at the secondary side, the noise filter having a conductance value that varies with frequency. The noise filter conductance comprises a peak conductance in a peak conductance frequency region. The noise filter is operable to reduce the common-mode noise of the switch mode power supply at frequencies occurring in the peak conductance frequency region.

Abstract: A switch mode power supply is described including a primary side for coupling to a mains supply and a secondary side for coupling to a device, an isolation transformer comprising a primary coil and a secondary coil and arranged to isolate the primary side from the secondary side, and a noise filter coupled between a primary ground at the primary side and a secondary ground at the secondary side, the noise filter having a conductance value that varies with frequency. The noise filter conductance comprises a peak conductance in a peak conductance frequency region. The noise filter is operable to reduce the common-mode noise of the switch mode power supply at frequencies occurring in the peak conductance frequency region.

Abstract: A circuit is disclosed for driving a plurality of LED strings from an AC supply and arranged to, in use, drive current through a series arrangement of a plurality N of the LED strings when the AC voltage is sufficient to drive the plurality N of the LED strings: the circuit comprising a first current source configured to be switchably connected to a one end of said series arrangement of N LED strings; a series combination of a second current source and a heat dissipater, wherein the series combination of the second current source and the heat dissipater is arranged in parallel with the first current source; and a current balancer for balancing the current through the first current source and the second current source. A driver for such a circuit is also disclosed.

Abstract: A DC/DC converter (1), comprising inductive electrical energy storage means (L), switching means (S1, S2) and control means (6). The control means (6) are arranged for selectively operating the switching means (S1, S2) for transferring an amount of electrical energy from the energy storage means (L) to an output of the DC/DC converter (1), for providing a desired output voltage (Vout), in accordance with a two-state switching cycle comprising a minimum and a maximum duty cycle (Dmin, Dmax).

Abstract: A DC/DC converter (1; 20), comprising inductive electrical energy storage means (L), switching means (S1-S4) and means (6; 15) wherein said control means (6; 15) are arranged for selectively operating said switching means (S1-S4) for transferring an amount of electrical energy from said energy storage means (L) to an output of said DC/DC converter (1; 20), for providing a desired output voltage (Vout), characterized by digital control means (6; 15) which are configured for operatively controlling said switching means (S1-S4) for transferring electrical energy in accordance with a switching sequence comprising a ramp-up switching cycle and a ramp-down cycle for substantially charging and decharging of the energy storage means (L).

Abstract: A DC/DC converter (1), comprising inductive electrical energy storage means (L), switching means (S1, S2) and control means (6).

Abstract: A DC/DC converter (1; 20), comprising inductive electrical energy storage means (L), switching means (S1-S4) and means (6; 15) wherein said control means (6; 15) are arranged for selectively operating said switching means (S1-S4) for transferring an amount of electrical energy from said energy storage means (L) to an output of said DC/DC converter (1; 20), for providing a desired output voltage (Vout), characterized by digital control means (6; 15) which are configured for operatively controlling said switching means (S1-S4) for transferring electrical energy in accordance with a switching sequence comprising a ramp-up switching cycle and a ramp-down cycle for substantially charging and decharging of the energy storage means (L).

Abstract: An electrical circuit arrangement (19), comprising an output stage (4) having an output terminal (2) for delivering an output current, and at least one feedback circuit (15, 16) operatively connected to the output terminal (2). A current generator circuit (20), arranged for generating a current which is a fraction of the output current, connects by a resistive element (21) to the output terminal (2), thereby providing improved high frequency feedback stability.

Abstract: An electrical circuit arrangement (19), comprising an output stage (4) having an output terminal (2) for delivering an output current, and at least one feedback circuit (15, 16) operatively connected to the output terminal (2). A current generator circuit (20), arranged for generating a current which is a fraction of the output current, connects by a resistive element (21) to the output terminal (2), thereby providing improved high frequency feedback stability.