Abstract:
A bleeder arrangement for a phase-cut circuit for a high-impedance load and having a leading-edge phase-cut device is disclosed, the bleeder arrangement comprising: a controllable current sink adapted to sink a latching current through the leading-edge phase-cut device, and a controller for controlling the controllable current sink, wherein the controller is configured to disable the current sink after the leading-edge phase phase-cut device has latched in at least two stages. A controller for use in such an arrangement is also disclosed, as is a method of controller such a bleeder arrangement.
Abstract:
A method of controlling a ballast in a circuit for a lighting application and connected to a mains power supply is disclosed. The method comprises determining whether a dimmer is present in the circuit; in response to detecting that a dimmer is present, determining a zero-crossing of the power supply and setting a bleeder current through the ballast in dependence on the phase of the power supply within a mains half-cycle; and in response to determining that a dimmer is not present, disabling the bleeder current.A ballast which is controlled by such a method is also disclosed. Additionally, a controller, which may include a digital signal processor, for a ballast and operable according to the above method is disclosed.
Abstract:
A bleeder arrangement for a phase-cut circuit for a high-impedance load and having a leading-edge phase-cut device is disclosed, the bleeder arrangement comprising: a controllable current sink adapted to sink a latching current through the leading-edge phase-cut device, and a controller for controlling the controllable current sink, wherein the controller is configured to disable the current sink after the leading-edge phase phase-cut device has latched in at least two stages. A controller for use in such an arrangement is also disclosed, as is a method of controller such a bleeder arrangement.