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 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 circuit for a dimmer system is disclosed, in which a phase-cut dimmer output signal is converted to a dimming control level signal. The phase-cut dimmer output signal is used to generated a pulse modulated signal indicative of the duty cycle of the phase cut dimmer output signal, and the pulse modulated signal is directly converted to a piece-wise linear dimming control level signal. By directly converting the pulse modulated signal to a piece-wise linear dimming control level signal, no further processing is necessary to produce a dimming signal which closely resembles the ideal logarithmic response of the human eye. A corresponding method for a dimmer system is also disclosed, as is a dimmer system.

Abstract: A switching circuit and a method of operating the same are disclosed. In an embodiment, the switching circuit includes a switching transistor adapted to control operation of the switching circuit according to a control signal applied to the control terminal of the switching transistor, a regulating circuit adapted to generate the control signal, and a detecting circuit adapted to sense a voltage at the control terminal when the switching transistor is in an OFF state and to generate a drive signal according to the sensed voltage. The regulating circuit is adapted to generate the control signal based on the generated drive 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 DC-DC converter for driving one or more LED (38), which converter comprises an integrated circuit (12) having a switch mode power circuit (24) and a 5 temperature sensing circuit (40) for providing an output indicating a temperature of said integrated circuit (12), the arrangement being such that, in use, said integrated circuit consumes power, some of which power is dissipated in said integrated circuit as heat causing a rise in said internal temperature, and wherein a change in said output from said temperature sensing circuit (40) is used by said integrated circuit to 10 adjust said consumed power whereby said internal temperature may be controlled.

Abstract: A switching circuit and a method of operating the same. The switching circuit comprises: a switching transistor adapted to control operation of the switching circuit according to a control signal applied to the control terminal of the switching transistor; a regulating circuit adapted to generate the control signal; and a detecting circuit adapted to sense a voltage at the control terminal when the switching transistor is in an OFF state and to generate a drive signal according to the sensed voltage. The regulating circuit is adapted to generate the control signal based on the generated drive signal.

Abstract: A circuit for a dimmer system is disclosed, in which a phase-cut dimmer output signal is converted to a dimming control level signal. The phase-cut dimmer output signal is used to generated a pulse modulated signal indicative of the duty cycle of the phase cut dimmer output signal, and the pulse modulated signal is directly converted to a piece-wise linear dimming control level signal. By directly converting the pulse modulated signal to a piece-wise linear dimming control level signal, no further processing is necessary to produce a dimming signal which closely resembles the ideal logarithmic response of the human eye. A corresponding method for a dimmer system is also disclosed, as is a dimmer system.

Abstract: A method of controlling a DC-DC converter is disclosed, which provides for compensation of the loop-delay caused by, for instance, delays in operation of the comparator. The method is exemplified with reference to, but not limited to, a hysteretic converter.

Abstract: A DC-DC converter for driving one or more LED (38), which converter comprises an integrated circuit (12) having a switch mode power circuit (24) and a 5 temperature sensing circuit (40) for providing an output indicating a temperature of said integrated circuit (12), the arrangement being such that, in use, said integrated circuit consumes power, some of which power is dissipated in said integrated circuit as heat causing a rise in said internal temperature, and wherein a change in said output from said temperature sensing circuit (40) is used by said integrated circuit to 10 adjust said consumed power whereby said internal temperature may be controlled