ADAPTATION CIRCUIT FOR COUPLING LED TO BALLAST

• US 20150054416A1
• Filed: 03/20/2013
• Published: 02/26/2015
• Est. Priority Date: 03/29/2012
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Radermacher, Harald Josef Gunther
• Granted Patent: US 9,445,465 B2
• Time in Patent Office: Days
• US Class Current: 315/200.R
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/30 Driver circuits
• CPC Class Codes: H05B 45/3578 Emulating the electrical or functional characteristics of discharge lamps
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

Adaptation circuits (1) allow discharge lamps to be replaced by light circuits (45) with light emitting diodes, while keeping ballast circuits (8) designed for connection to the discharge lamps. The adaptation circuits (1) comprise conversion circuits (2) for converting input voltage and current signals coming from the ballast circuits (8) into output voltage and current signals destined for the light circuits (45). The conversion circuits (2) reduce amplitudes of the input voltage signals to values below predefined values during predefined time intervals after energy from the ballast circuits (8) has been transferred to the conversion circuits (2). The time intervals are synchronized with periods of the input voltage signals. Between first draining states for draining energy and second releasing states for releasing the energy, third states such as holding states for holding the energy have been introduced. The third states allow relevant values as experienced by the ballast circuits (8) to remain comparable to situations when the discharge lamps were powered.

Claims

1. An adaptation circuit for coupling a light circuit to a ballast circuit, the light circuit comprising at least one light emitting diode, the ballast circuit arranged for connection to a discharge lamp using a first amount of power, the light circuit being designed to use a second amount of power, the adaptation circuit comprising a conversion circuit for converting an input voltage signal and an input current signal coming from the ballast circuit into an output voltage signal and an output current signal for the light circuit, the conversion circuit being adapted to

drain energy from the ballast circuit, and

reduce an amplitude of the input voltage signal to a value below a predefined value during a predefined time interval after the energy from the ballast circuit has been transferred to the conversion circuit, the predefined time interval being synchronized with at least one period of the input voltage signal.

2. The adaptation circuit of claim 1, the conversion circuit further arranged to

hold the energy during a reduction of the amplitude of the input voltage signal to the value or another value below the predefined value, and

release the energy.

3. The adaptation circuit of claim 1, the conversion circuit comprising at least a reactive element for storing the energy, a switch for, in combination with the reactive element, reducing the amplitude of the input voltage signal to the value below the predefined value during the predefined time interval, and a timer circuit for controlling the switch.

4. The adaption circuit of claim 3, the timer circuit comprising an adjustable timer circuit for adjusting the operation of the switch in dependence on the second amount of power.

5. The adaption circuit of claim 3, the conversion circuit further comprising a capacitor, the reactive element comprising an inductor,

wherein a first terminal of the inductor is coupled to a first input terminal of the conversion circuit,

wherein a second terminal of the inductor is coupled to a first terminal of the diode,

wherein a second terminal of the diode is coupled to a first terminal of the capacitor,

wherein a second terminal of the capacitor is coupled to a second input terminal of the conversion circuit,

wherein each terminal of the capacitor is coupled to each of the output terminals of the conversion circuit,

wherein a first contact of the switch is coupled to the first terminal of the diode and to a second contact of the switch is coupled to the the second terminal of the capacitor.

6. The adaptation circuit of claim 3, wherein the conversion circuit comprises a trigger circuit for triggering the timer circuit.

7. The adaptation circuit of claim 6, wherein the trigger circuit is adapted to deactivate the switch upon start-up.

8. The adaptation circuit of claim 6, wherein the trigger circuit comprises:

a definition circuit for defining a time parameter and/or a voltage level, and

a decision circuit coupled to the definition circuit arranged to provide a trigger signal to the timer circuit.

9. The adaptation circuit of claim 8, wherein the definition circuit comprises:

a serial circuit of one or more first resistors,

one or more voltage defining circuits, and

a capacitor,

wherein the capacitor is coupled in parallel to a second resistor,

wherein the definition circuit is coupled in parallel to the conversion circuit, and

wherein the decision circuit comprises a transistor the transistor comprising a control electrode coupled to the definition circuit and a main electrode providing the trigger signal.

10. The adaptation circuit of claim 9, the trigger circuit further comprising a switch bridging at least a part of the definition circuit arranged to deactivate a reduction of the amplitude of the input voltage signal to the value below the predefined value upon start-up.

11. The adaptation circuit of claim 1, wherein the conversion circuit comprises a rectification circuit connected to the ballast circuit.

12. A device comprising the adaptation circuit of claim 1 further comprising the ballast circuit.

13. A device comprising the adaptation circuit of claim 1 further comprising the light circuit (45).

16. The adaptation circuit of claim 1, wherein the second amount of power is different than the first amount of power.

17. The adaptation circuit of claim 6, wherein the trigger circuit is adapted to deactivate the switch when a certain time interval has passed.

18. The adaptation circuit of claim 6, wherein the trigger circuit is adapted to deactivate the switch when a certain state has been reached.

19. The adaptation circuit of claim 9, the trigger circuit further comprising a switch bridging at least a part of the definition circuit arranged to deactivate a reduction of the amplitude of the input voltage signal to the value below the predefined value when a certain time interval has passed.

20. The adaptation circuit of claim 9, the trigger circuit further comprising a switch bridging at least a part of the definition circuit arranged to deactivate a reduction of the amplitude of the input voltage signal to the value below the predefined value when a certain state has been reached.

14. A method of coupling a light circuit to a ballast circuit, wherein the light circuit comprises at least one light emitting diode, the ballast circuit is arranged to connect to a discharge lamp using a first amount of power, the light circuit is arranged to use a second amount of, the method comprising:

converting an input voltage signal and an input current signal coming from the ballast circuit into an output voltage signal and an output current signal for the light circuit, the conversion comprising,

draining energy from the ballast circuit, and

reducing an amplitude of the input voltage signal to a value below a predefined value during a predefined time interval after the energy from the ballast circuit has been transferred tot he conversion circuit,

wherein the predefined time interval is synchronized with at least one period of the input voltage signal.

15. (canceled)