BLEEDER CIRCUIT

• US 20120126714A1
• Filed: 07/27/2010
• Published: 05/24/2012
• Est. Priority Date: 07/27/2009
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Deppe, Carsten, Sauerländer, Georg
• Granted Patent: US 8,723,431 B2
• Time in Patent Office: Days
• US Class Current: 315/192
• CPC Class Codes: H05B 45/3575 by means of dummy loads or bleeder circuits, e.g. for dimmers

Abstract

Bleeder circuits (1) for combinations of phase cutting dimmers (2) and light emitting diode circuits (3) comprise active circuitry (4) to increase a number of options. The active circuitry (4) may comprise a current limiting circuit (5) for limiting a current flowing through the bleeder circuit (1). The active circuitry (4) may comprise a voltage detecting circuit (6) for activating or deactivating, in response to a detection result, the current limiting circuit (5) and may comprise control circuitry such as a micro processor circuit (7) for controlling the current limiting circuit (5) and may comprise a control circuit (9) for using information derived from a current flowing through the light emitting diode circuit (3) for controlling the current limiting circuit (5) and for controlling at least a part of the light emitting diode circuit (3) that comprises anti-parallel light emitting diodes (31-32) or serial and/or parallel light emitting diodes (33-36).

Claims

1. A bleeder circuit for a combination of a phase cutting dimmer and a light emitting diode circuit, the bleeder circuit comprising active circuitry, the active circuitry comprising

a current limiting circuit for limiting a current flowing through the bleeder circuit, and

a control circuit for controlling the current limiting circuit based on information derived from a current flowing through the light emitting diode circuit.

2. The bleeder circuit as defined in claim 1, wherein the control circuit is connected to an input and an output of the current limiting circuit.

3. The bleeder circuit as defined in claim 2, the current limiting circuit comprising a parallel connection of first and second serial connections, the first serial connection comprising a first resistor and a voltage reference element, the second serial connection comprising a second resistor and a transistor, a control electrode of the transistor being connected to an interconnection between the first resistor and the voltage reference element, the interconnection being the input of the current limiting circuit, a further interconnection between the second resistor and the transistor being the output of the current limiting circuit.

4. The bleeder circuit as defined in claim 1, wherein the active circuitry further comprises a voltage detecting circuit for in response to a detection result activating or deactivating the current limiting circuit.

5. The bleeder circuit as defined in claim 4, wherein the voltage detecting circuit comprises a third serial connection of third and fourth resistors and comprising a further transistor, a control electrode of the further transistor being connected to an interconnection between the third and fourth resistors, and a main electrode of the further transistor being connected to an input of the current limiting circuit.

6. The bleeder circuit as defined in claim 1, wherein the active circuitry further comprises a micro processor circuit for controlling the current limiting circuit.

7. The bleeder circuit as defined in claim 1, wherein the information derived from the current flowing through the light emitting diode circuit comprises a size of this current and/or a starting or finishing point in time of this current, said controlling of the current limiting circuit comprising an adaptation of a reduced value of the current flowing through the bleeder circuit and/or an activation or deactivation of the current limiting circuit and/or the active circuitry.

8. The bleeder circuit as defined in claim 1, wherein the light emitting diode circuit comprises anti-parallel light emitting diodes, the bleeder circuit further comprising a rectifier for converting a first voltage into a second voltage, the first voltage being an AC voltage for feeding the light emitting diode circuit, and the second voltage being a DC voltage for feeding the active circuitry.

9. The bleeder circuit as defined in claim 1, wherein the light emitting diode circuit comprises serial and/or parallel light emitting diodes, the bleeder circuit further comprising a rectifier for converting a first voltage into a second voltage, the first voltage being an AC voltage, and the second voltage being a DC voltage for feeding the light emitting diode circuit and the active circuitry.

10. The bleeder circuit as defined in claim 9, wherein the control circuit is connected to an interconnection between a fifth resistor and the serial and/or parallel light emitting diodes.

11. The bleeder circuit as defined in claim 10, wherein the control circuit is further connected to an interconnection between two or more of the serial and/or parallel light emitting diodes for further controlling at least a part of the light emitting diode circuit.

12. The bleeder circuit as defined in claim 1, wherein the active circuitry further comprises a dimmer detecting circuit for in response to a detection result activating or deactivating the bleeder circuit.

13. A light emitting diode circuit comprising the bleeder circuit as defined in claim 1.

14. A phase cutting dimmer comprising the bleeder circuit as defined in claim 1.

15. A device comprising the bleeder circuit as defined in claim 1 and further comprising a light emitting diode circuit and/or a phase cutting dimmer and/or a stabilization load for a phase cutting dimmer.