Abstract: Lighting circuits and luminaires and methods are disclosed which are operable with a phase-cut dimmer, A circuit can include a rectifier having a low side output and a high side output, a switched mode converter including a switch and an inductor, having a high side input connected to a bus rail, and having a configuration to draw current across a complete mains cycle a controller for the switched mode converter, a filter circuit connected between the rectifier high side output and the bus rail and including a capacitor connected between the high side output of the mains rectifier and ground, and a resistance connected between the low side output of the rectifier and ground. The value of the resistance may be such the RC time constant of the resistor and filter circuit is greater than the time required for any ringing in the circuit to fall to no more than 20 mA.

Abstract: A filter circuit comprising a first feedback circuit configured to: receive a sensed-voltage-level-signal representative of a sensed voltage across a current sensing element; receive a voltage-set-point-signal; and set a regulation-control-signal for a current regulation device such that the sensed-voltage-level-signal tends towards the voltage-set-point-signal. The filter circuit also comprises a second feedback circuit configured to: receive a predetermined-threshold-signal; and receive a regulation-control-voltage-signal, representative of a voltage level of the regulation-control-signal. The second feedback circuit is configured to adjust the voltage-set-point-signal in accordance with a comparison between the regulation-control-voltage-signal and the predetermined-threshold-signal.

Abstract: The disclosure relates to a controller (606) for a switched mode power supply, SMPS (600), comprising: a switch toggling unit (670) having a first switching mode and a second switching mode, wherein the first switching mode is a continuous conduction mode or a boundary conduction mode and the second conduction mode is a discontinuous conduction mode; and a switch mode selector (676) configured to set the switching mode of the switch toggling unit (670) in accordance with a current in an inductor (602) of the SMPS (600).

Abstract: Lighting circuits and luminaires and methods are disclosed which are operable with a phase-cut dimmer, each circuit comprising a rectifier having a low side output and a high side output; a switched mode converter comprising a switch and an inductor, having a high side input connected to a bus rail, and having a configuration to draw current across a complete mains cycle; a controller for the switched mode converter; a filter circuit connected between the rectifier high side output and the bus rail and comprising a capacitor connected between the high side output of the mains rectifier and ground; and a resistance connected between the low side output of the rectifier and ground. The value of the resistance may be such the RC time constant of the resistor and filter circuit is greater than the time required for any ringing in the circuit to fall to no more than 20 mA.

Abstract: A filter circuit comprising a first feedback circuit configured to: receive a sensed-voltage-level-signal representative of a sensed voltage across a current sensing element receive a voltage-set-point-signal; and set a regulation-control-signal for a current regulation device such that the sensed-voltage-level-signal tends towards the voltage-set-point-signal. The filter circuit also comprises a second feedback circuit configured to: receive a predetermined-threshold-signal; and receive a regulation-control-voltage-signal, representative of a voltage level of the regulation-control-signal. The second feedback circuit is configured to adjust the voltage-set-point-signal in accordance with a comparison between the regulation-control-voltage-signal and the predetermined-threshold-signal.

Abstract: A bleeder circuit controller (11) configured to control a bipolar junction transistor (10) having a collector (12) configured to be connected to an output of a phase cut dimmer (2) for receiving a bleed current, an emitter (13) for connecting to ground and a base (14), the bleeder circuit controller configured to generate a control signal for controlling the bleed current through the bipolar junction transistor (10) and measure a signal indicative of the current flow through the dimmer (2) and apply a current limit to a base-emitter current flow as a function of the measured signal.

Abstract: A switched mode power supply comprising: a rectified voltage terminal and a rectified ground terminal for receiving a phase-cut rectified voltage; a power switch and an inductive element connected in series between the rectified voltage terminal and the rectified ground terminal; a switch controller having a floating ground terminal and a dimming input terminal, wherein the dimming input terminal is for receiving a dimming voltage signal indicative of a required dimming level, wherein the switch controller is configured to control the switch in accordance with the dimming voltage signal and wherein the inductive element is connected between the rectified ground terminal and the floating ground terminal; and a dimming level controller configured to set the dimming voltage signal in accordance with the rectified phase-cut voltage with respect to the floating ground terminal.

Abstract: Lighting circuits and luminaires and methods are disclosed which are operable with a phase-cut dimmer. A circuit includes a rectifier having a low side output and a high side output, a switched mode converter including a switch and an inductor, having a high side input connected to a bus rail, and having a configuration to draw current across a complete mains cycle, a controller for the switched mode converter, a filter circuit connected between the rectifier high side output and the bus rail and including a capacitor connected between the high side output of the mains rectifier and ground, and a resistance connected between the low side output of the rectifier and ground. The value of the resistance may be such the RC time constant of the resistor and filter circuit is greater than the time required for any ringing in the circuit to fall to no more than 20 mA.

Abstract: In an example embodiment, a controller generates a switch signal for controlling a switch to convert an input signal from a phase cut dimmer into a driving signal for a solid state lighting element. The controller determines a conduction period of the input signal from the phase cut dimmer within a half cycle period of the input signal, determines a burst period within the conduction period is a period of time less than the conduction period, and generates a switch signal comprising a plurality of switching cycles over the burst period. The switch signal has first and second subsets of switching cycles. The controller controls the switching cycles of the second subset such that the average energy transferred per switching cycle to the driving signal is less than the average energy transferred per switching cycle to the driving signal for the switching cycles of the first subset.

Abstract: Controllers (360, 360?), lighting circuits and methods are disclosed, for a dimmable LED lighting circuit having a series arrangement of two types of LED, the controller comprising a control circuit (330), a bypass circuit (340) and optionally a further bypass circuit and being operable for controlling a current, the current (Idriver) being separable into first and second parts (IW, IB), and into further first and second parts, wherein the controller is configured to direct the (further) first part through the LED or LEDs of the second (first) type and direct the (further) second part through the (further) bypass circuit (respectively), and wherein the control circuit is configured to adjust the ratio between the first, or further first, part and the second, or further second respectively, part in dependence on a dimming level of the LED lighting circuit.

Abstract: A circuit and lighting unit for dimmable lighting applications are disclosed, the circuit comprising: a controllable current supply having a positive output and a negative output and being for supplying current to at most one of a first path and a second path, the first and second path each comprising, in use, a series arrangement of a switch and an LED string; the switches each having a respective input, output, and control terminal, the respective inputs being connected in common to a one of the outputs of the controllable current supply, and an open/closed switching status of each switch being selectable by a respective switching signal at its respective control terminal; wherein the second path switch control terminal is electrically coupled to the first path switch output such that the second switching signal is inverted relative to the first switching signal.

Abstract: A switched mode power supply comprising: a rectified voltage terminal and a rectified ground terminal for receiving a phase-cut rectified voltage; a power switch and an inductive element connected in series between the rectified voltage terminal and the rectified ground terminal; a switch controller having a floating ground terminal and a dimming input terminal, wherein the dimming input terminal is for receiving a dimming voltage signal indicative of a required dimming level, wherein the switch controller is configured to control the switch in accordance with the dimming voltage signal and wherein the inductive element is connected between the rectified ground terminal and the floating ground terminal; and a dimming level controller configured to set the dimming voltage signal in accordance with the rectified phase-cut voltage with respect to the floating ground terminal.

Abstract: Lighting circuits and luminaires and methods are disclosed which are operable with a phase-cut dimmer, each circuit comprising a rectifier having a low side output and a high side output; a switched mode converter comprising a switch and an inductor, having a high side input connected to a bus rail, and having a configuration to draw current across a complete mains cycle; a controller for the switched mode converter; a filter circuit connected between the rectifier high side output and the bus rail and comprising a capacitor connected between the high side output of the mains rectifier and ground; and a resistance connected between the low side output of the rectifier and ground. The value of the resistance may be such the RC time constant of the resistor and filter circuit is greater than the time required for any ringing in the circuit to fall to no more than 20 mA.

Abstract: The disclosure relates to a controller (606) for a switched mode power supply, SMPS (600), comprising: a switch toggling unit (670) having a first switching mode and a second switching mode, wherein the first switching mode is a continuous conduction mode or a boundary conduction mode and the second conduction mode is a discontinuous conduction mode; and a switch mode selector (676) configured to set the switching mode of the switch toggling unit (670) in accordance with a current in an inductor (602) of the SMPS (600).

Abstract: A bleeder circuit controller (11) configured to control a bipolar junction transistor (10) having a collector (12) configured to be connected to an output of a phase cut dimmer (2) for receiving a bleed current, an emitter (13) for connecting to ground and a base (14), the bleeder circuit controller configured to generate a control signal for controlling the bleed current through the bipolar junction transistor (10) and measure a signal indicative of the current flow through the dimmer (2) and apply a current limit to a base-emitter current flow as a function of the measured signal.

Abstract: In an example embodiment, a controller generates a switch signal for controlling a switch to convert an input signal from a phase cut dimmer into a driving signal for a solid state lighting element. The controller determines a conduction period of the input signal from the phase cut dimmer within a half cycle period of the input signal, determines a burst period within the conduction period is a period of time less than the conduction period, and generates a switch signal comprising a plurality of switching cycles over the burst period. The switch signal has first and second subsets of switching cycles. The controller controls the switching cycles of the second subset such that the average energy transferred per switching cycle to the driving signal is less than the average energy transferred per switching cycle to the driving signal for the switching cycles of the first subset.

Abstract: Controllers (360, 360?), lighting circuits and methods are disclosed, for a dimmable LED lighting circuit having a series arrangement of two types of LED, the controller comprising a control circuit (330), a bypass circuit (340) and optionally a further bypass circuit and being operable for controlling a current, the current (Idriver) being separable into first and second parts (IW, IB), and into further first and second parts, wherein the controller is configured to direct the (further) first part through the LED or LEDs of the second (first) type and direct the (further) second part through the (further) bypass circuit (respectively), and wherein the control circuit is configured to adjust the ratio between the first, or further first, part and the second, or further second respectively, part in dependence on a dimming level of the LED lighting circuit.